1.2: Wireless Technology and Amateur Radio - What and Why?
By the end of this section, you will be able to
- Define wireless technology, and provide some examples of it.
- Define Amateur Radio, and provide some examples of how Amateur Radio is used in practice.
Wireless technology is equipment or methods that enable information to be transferred between two locations without an electrical wire, optical fiber, or other guiding medium [1]. Wireless equipment most commonly uses electromagnetic waves to send signals through air or empty space from a sender to a receiver. Contemporary examples of wireless technology include cellular telephones, broadcast and satellite televisions, broadcast AM/FM radio receivers, remote garage door openers, remote controls, cordless telephones and headphones, wireless computer mice and keyboards, Global Positioning System (GPS) receivers, handheld radios ("walkie-talkies"), Amateur Radio transceivers, and other devices that use wireless communication protocols like WiFi and Bluetooth [1] (Fig. \(\PageIndex{1}\)). The development of wireless technology combined with the development of small, high-capacity batteries has led to the widespread adoption of wireless devices due to their convenience and portability.
Amateur Radio , also known as ham radio , is one of several personal radio services which use wireless technology to enable licensed operators to communicate. As suggested by the name, Amateur Radio operators are restricted to using radio for non-commercial purposes [5]. In contrast to other personal radio services (see Table \(\PageIndex{1}\)) which are typically limited to local use, amateur radio stations can often communicate with other stations around the world given their higher allowed power levels and wider access to the electromagnetic spectrum. To gain access to these privileges, Amateur Radio operators must typically be licensed by their local government agency (e.g., the Federal Communications Commission (FCC) [6] in the United States) and demonstrate some understanding of the key concepts of electricity and magnetism, electronics, radio equipment, radio wave propagation, radio-frequency safety, and local operating regulations and conventions. It is this overlap between the physics of electromagnetism and the topics of Amateur Radio that make it natural to consider both in the same context.
| Service | Channels | Intended Use | Typical Range |
|---|---|---|---|
| Citizens Band | 40 | Private/Business | 16 km (10 miles) |
| Marine VHF | 50 | Maritime | 32 km (20 miles) |
| Family Radio Service (FRS) & General Mobile Radio Service (GMRS) | 22 | Personal | 3.2 km (2 miles) |
| Multi-Use Radio Service (MURS) | 5 | Personal | 8 km (5 miles) |
Amateur Radio operators have also developed interesting and novel ways to use radio signals (see Example
Amateur Radio operators have expanded the service and hobby into a wide variety of directions:
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Wireless
Experimentation & Technical Development
As wireless technology developed, Amateur Radio operators were involved in its progress. For example, in the United States, the first Amateur Radio licenses were issued in 1912 [7], not long after the first demonstration of radio communication in the 1890s and early 1900s [8]. Over time, Amateur Radio operators have worked to develop and refine techniques to send images, video, text messages, email, data packets, and other information formats via radio signals. They have also develop and test methods to successfully communicate messages under conditions with a lot of noise or with low power. -
Emergency Communications
Amateur Radio operators are also known for their use of radio in emergency communications and other public service applications [9]. For example, Amateur Radio networks are often activated during hurricanes and other extreme weather events when other means of communications like cellular networks are down due to power outages. In the United States, programs like the American Radio Relay League's Amateur Radio Emergency Service (ARES) and the government's Radio Amateur Civil Emergency Service (RACES) prepare operators to work with local agencies in times of crisis and report severe weather conditions to the National Weather Services via the SKYWARN organization. -
Radiosport (Contesting)
Amateur Radio operators have developed many different ways to practice their operating skills in competition with each other [10]. During contests, operators try to make as many two-way contacts with other operators within a fixed duration of time, often with different categories (e.g., operating teams, operating at low power, operating in different part of the spectrum). Formal or informal contests are also held to test operators' ability to receive or transmit quickly using Morse code, find hidden transmitters (Amateur Radio Direction Finding or "foxhunting"), or quickly deploy, contact, and move to a new location repeatedly (Rapid Deployment of Amateur Radio). -
Remote Communication
Amateur Radio operators practice their transmitting and receiving skills by making contacts with many different geographic regions as possible [11]. Operators may try to work all countries, states, counties, or other entities from their own local station. Some operators take part in expeditions to set up stations in remote locations to make contacts ("DXpeditions" where "DX" is radio shorthand for "distant") or in specific kinds of geographic entities (e.g., Parks on the Air (POTA), Summits on the Air (SOTA), Islands on the Air (IOTA)). Other operators specialize in making long-distance contacts via orbiting satellites or via temporary conditions like aurora (Northern or Southern lights) or meteor showers that would otherwise be difficult to perform. -
Radio Clubs
Amateur Radio operators have formed a variety of organizations to support Amateur Radio [12]. These clubs provide networking, formal or informal education about radio, licensing exams, "hamfests" to buy or sell radio gear, contesting events, field days, and other opportunities. Organizations have been developed to support operators in a common geographic area, with common background (e.g., Collegiate Amateur Radio Program (CARP) for college and university students, Youth on the Air (YOTA) for operators under 25 years old, Young Ladies Radio League for women of all ages) or common interests (e.g, Morse code, radiosport, remote communication, satellite communication). Many countries have national organizations (e.g., the American Radio Relay League, Radio Amateurs of Canada, Radio Society of Great Britain) that help to design and administer license exams, advocate for public policies to protect the Amateur Radio service, perform technical testing of radio equipment, and develop educational materials. -
Citizen Science
While much more is known about radio waves than in the early 1900s, there is still much to be learned, particularly about how radio waves travel from location to location through the atmosphere and ionosphere surrounding the earth. Collaborations between the professional scientists & engineers at universities and government agencies and the broader community of citizen Amateur Radio operators can enable accelerated development of new radio technology and improved understanding of radio wave propagation. For example, the Ham Radio Science Citizen Investigation (HamSCI) [13] has studied how radio wave propagation changes during a total solar eclipse by crowd-sourcing contact reports from the Amateur Radio community.
These videos illustrate some examples of these various aspects of Amateur Radio.
References
- Wikipedia contributors. Wireless [Internet]. Wikipedia, The Free Encyclopedia.
- Freestocks.org. iPhone on a wooden bench [Internet]. Freestocks.org. (CC0)
- Bird M. Turned on black gps monitor [Internet]. Pexels.com. (Free to use)
- SHVETS production. Black entrepreneur typing on convenient wireless keyboard [Internet]. Pexels.com (Free to use)
- Wikipedia contributors. Amateur radio [Internet]. Wikipedia, The Free Encyclopedia.
- Federal Communications Commission. Amateur radio service [Internet]. Federal Communications Commission.
- American Radio Relay League (ARRL). The ARRL ham radio license manual. Newington, CT: ARRL (2022).
- Wikipedia contributors. Wireless telegraphy [Internet]. Wikipedia, The Free Encyclopedia.
- American Radio Relay League (ARRL). Public service [Internet]. ARRL.
- Wikipedia contributors. Radiosport [Internet]. Wikipedia, The Free Encyclopedia.
- Wikipedia contributors. DXing [Internet]. Wikipedia, The Free Encyclopedia.
- American Radio Relay League (ARRL). Clubs [Internet]. ARRL.
- Ham Radio Science Citizen Investigation (HamSCI). HamSCI [Internet]. HamSCI.


4.3.8: Summary
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- Jamie Hammond and Western Technical College
- OpenStax
Key Terms
- Bounded rationality
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The concept that when we make decisions, we cannot be fully rational because we don’t have all the possible information or the cognitive processing ability to make fully informed, completely rational decisions.
- Brainstorming
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A process of generating as many ideas or alternatives as possible, often in groups.
- Confirmation Bias
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The tendency to pay attention to information that confirms our existing beliefs and to ignore or discount information that conflicts with our existing beliefs.
- Creativity
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The generation of new or original ideas.
- Critical Thinking
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A disciplined process of evaluating the quality of information, especially by identifying logical fallacies in arguments.
- Decision-making
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The action or process of thinking through possible options and selecting one.
- Devil's Advocate
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A group member who intentionally takes on the role of being critical of the group’s ideas in order to discourage groupthink and encourage deep thought and discussion about issues prior to making decisions.
- Emotional Intelligence
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The ability to understand and manage emotions in oneself and in others.
- Escalation of Commitment
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The tendency of decision makers to remain committed to poor decision, even when doing so leads to increasingly negative outcomes.
- Evidence-based Decision-making
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A process of collecting the best available evidence prior to making a
decision.
- Groupthink
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The tendency of a group to reach agreement very quickly and without substantive discussion.
- Heuristics
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Mental shortcuts that allow a decision maker to reach a good decision quickly. They are strategies that develop based on prior experience.
- Nonprogrammed Decisions
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Decisions that are novel and not based on well-defined or known criteria.
- Process conflict
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Conflict about the best way to do something; conflict that is task-oriented and constructive, and not focused on the individuals involved.
- Programmed Decision
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Decisions that are repeated over time and for which an existing set of rules can be
developed.
- Reactive System
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System of decision-making in the brain that is quick and intuitive.
- Reflective System
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System of decision-making in the brain that is logical, analytical, and methodical.
- Relationship Conflict
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Conflict between individuals that is based on personal (or personality) differences; this type of conflict tends to be destructive rather than constructive.
- Satisficing
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Choosing the first acceptable solution to minimize time spent on a decision.
- Stakeholders
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Individuals or groups who are impacted by the organization. These include owners, employees, customers, suppliers, and members of the community in which the organization is located.
- Suppression of Dissent
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When a group member exerts his or her power to prevent others from voicing their thoughts or opinions.
Summary of Learning Outcomes
2.2 Overview of Managerial Decision-Making
1. What are the basic characteristics of managerial decision-making?
Managers are constantly making decisions, and those decisions often have significant impacts and implications for both the organization and its stakeholders. Managerial decision-making is often characterized by complexity, incomplete information, and time constraints, and there is rarely one right answer. Sometimes there are multiple good options (or multiple bad options), and the manager must try to decide which will generate the most positive outcomes (or the fewest negative outcomes). Managers must weigh the possible consequences of each decision and recognize that there are often multiple stakeholders with conflicting needs and preferences so that it often will be impossible to satisfy everyone. Finally, managerial decision-making can sometimes have ethical implications, and these should be contemplated before reaching a final decision.
2.3 How the Brain Processes Information to Make Decisions: Reflective and Reactive Systems
2. What are the two systems of decision-making in the brain?
The brain processes information to make decisions using one of two systems: either the logical, rational (reflective) system or the quick, reactive system. The reflective system is better for significant and important decisions; these generally should not be rushed. However, the reactive system can be lifesaving when time is of the essence, and it can be much more efficient when based on developed experience and expertise.
2.4 Programmed and Nonprogrammed Decisions
3. What is the difference between programmed and nonprogrammed decisions?
Programmed decisions are those that are based on criteria that are well understood, while nonprogrammed decisions are novel and lack clear guidelines for reaching a solution. Managers can establish rules and guidelines for programmed decisions based on known fact, which enables them to reach decisions quickly. Nonprogrammed decisions require more time to resolve; the decision maker may need to conduct research, collect additional information, gather opinions and ideas from other people, and so on.
2.5 Barriers to Effective Decision-Making
4. What barriers exist that make effective decision-making difficult?
There are numerous barriers to effective decision-making. Managers are limited in their ability to collect comprehensive information, and they are limited in their ability to cognitively process all the information that is available. Managers cannot always know all the possible outcomes of all the possible options, and they often face time constraints that limit their ability to collect all the information that they would like to have. In addition, managers, like all humans, have biases that influence their decision-making, and that can make it difficult for them to make good decisions. One of the most common biases that can confound decision-making is confirmation bias, the tendency for a person to pay attention to information that confirms her existing beliefs and ignore information that conflicts with these existing beliefs. Finally, conflict between individuals in organizations can make it challenging to reach a good decision.
2.6 Improving the Quality of Decision-Making
5. How can a manager improve the quality of her individual decision-making?
Managers tend to get better at decision-making with time and experience, which helps them build expertise. Heuristics and satisficing can also be useful techniques for making programmed decisions quickly. For nonprogrammed decisions, a manager can improve the quality of her decision-making by utilizing a variety of other techniques. Managers should also be careful to not skip steps in the decision-making process, to involve others in the process at various points, and to be creative in generating alternatives. They should also engage in evidence-based decision-making: doing research and collecting data and information on which to base the decision. Effective managers also think critically about the quality of the evidence that they collect, and they carefully consider long-term outcomes and ethical implications prior to making a decision.
2.7 Group Decision-Making
6. What are the advantages and disadvantages of group decision-making, and how can a manager improve the quality of group decision-making?
Groups can make better decisions than individuals because group members can contribute more knowledge and a diversity of perspectives. Groups will tend to generate more options as well, which can lead to better solutions. Also, having people involved in making decisions that will affect them can improve their attitudes about the decision that is made. However, groups sometimes fail to generate added value in the decision-making process as a result of groupthink, conflict, or suppression of dissent.
Managers can improve the quality of group decision-making in a number of ways. First, when forming the group, the manager should ensure that the individual group members are diverse in terms of knowledge and perspectives. The manager may also want to assign a devil’s advocate to discourage groupthink. Managers should also encourage all group members to contribute their ideas and opinions, and they should not allow a single voice to dominate. Finally, they should not allow personality conflicts to derail group processes.
Chapter Review Questions
- What are some of the factors that enabled to Jen Rubio and Stephanie Korey to make good decisions when they established their luggage company, Away?
- What are the two systems that the brain uses in decision-making? How are they related to programmed and nonprogrammed decisions?
- What is a heuristic, and when would it be appropriate to use a heuristic for decision-making?
- What is confirmation bias? Explain how it can be a barrier to effective decision-making.
- What is a logical fallacy?
- What are the two types of conflict? Which one is constructive, and which is destructive?
- What are the steps in the decision-making process? Which ones do people tend to skip or spend insufficient time on?
- What can individuals do to improve the quality of their decision-making?
- What can groups or group leaders do to improve the quality of group decision-making?
- What are the benefits of decision-making in a group, instead of individually?
Management Skills Application Exercises
- If you wanted to buy a new car, what research would you do first to increase the likelihood of making a good decision? As a manager, do you think you would engage in more research or less research than that prior to making big decisions for the organization?
- Think about a big decision that you have made. What impact did your emotions have on that decision? Did they help or hinder your decision-making? Would you make the same decision again?
- If you were faced with an ethical dilemma at work, who would you want to talk to for advice prior to reaching a decision?
- Which would be better to involve a group with, a programmed or a nonprogrammed decision? Why?
- If you were manager of a group with a lot of personality conflict, what would you do?
Managerial Decision Exercises
- Imagine that you are a manager and that two of your employees are blaming one another for a recent project not going well. What factors would you consider in deciding whom to believe? Who else would you talk to before making a decision? What would you do to try to reduce the likelihood of this happening again?
- You have been asked whether your organization should expand from selling its products only in North America to selling its products in Europe as well. What information would you want to collect? Who would you want to discuss the idea with before making a decision?
- You have a colleague who decided the organization should pursue a new technology. Nine months into the project of transitioning to the new technology, based on new information you are convinced that the new technology is not going to work out as anticipated. In fact, you expect it to be a colossal failure. However, when you try to talk to your colleague about the issue, she won’t listen to your arguments. She is adamant that this new technology is the correct direction for your organization. Why do you think she is so resistant to seeing reason? Given what you learned in this chapter, what could you do to persuade her?
- Your manager has asked you to take the lead on a new and creative project. She has encouraged you to create your own team (from existing employees) to work with you on the project. What factors would you want to consider in deciding who should join your project team? What would you want to do as the team leader to increase the likelihood that the group will be successful?
- Identify the logical flaw(s) in this argument:
- We want to have effective leaders in this organization.
- Taller individuals tend to be perceived as more leader-like.
- Men are usually taller than women.
- So, we should only hire men to be managers in our organization.
Critical Thinking Case
Vinyl Records Make a Comeback
The music industry has seen a series of innovations that have improved audio quality—vinyl records sales were eventually surpassed by compact discs in the 1980s, which were then eclipsed by digital music in the early 2000s. Both of the newer technologies boast superior sound quality to vinyl records. Vinyl should be dead . . . yet it’s not. Some say this is simply a result of nostalgia—people love to harken back to older times. However, some audiophiles say that vinyl records produce a “warm” sound that can’t be reproduced in any other format. In addition, a vinyl record is a tangible product (you can feel it, touch it, and see it when you own the physical record) and is more attractive, from an aesthetic perspective, than a CD. It is also a format that encourages listening to an entire album at once, rather than just listening to individual tracks, which can change the listening experience.
Whatever the reasons, vinyl is making an impressive comeback. Sales growth has been in the double digits for the last several years (over 50% in 2015 and again in 2016) and is expected to exceed $5 billion in 2017. Sony, which hasn’t produced a vinyl record since 1989, recently announced that it is back in the vinyl business.
One of the biggest challenges to making vinyl records is that most of the presses are 40+ years old. In the record-making process, vinyl bits are heated to 170 degrees, and then a specialized machine exerts 150 tons of pressure to press the vinyl into the shape of the record. About a dozen new vinyl record manufacturers have sprung up in the last decade in the United States. Independent Record Pressing, a company based in New Jersey, began producing vinyl records in 2015 using old, existing presses. Their goal upon starting up was to produce over a million records a year. Even at that level of production, though, demand far outstrips the company’s capacity to produce because of the limited number of presses available. They could run their machines nonstop, 24 hours a day, and not catch up with demand.
The big question is what the future holds for this industry. Will this just be a passing fad? Will the vinyl record industry remain a small niche market? Or is this the renaissance, the rebirth of a product that can withstand the test of time and alternative technologies? If it’s a rebirth, then we should see demand continue to grow at its recent rapid pace . . . and if demand remains strong, then investing in new presses may well be worthwhile. If this is just a short-lived nostalgic return to an outdated media, however, then the large capital investment required to purchase new presses will never be recouped. Even with the recent growth, vinyl records still accounted for only 7% of overall music industry sales in 2015. That may be enough to get old presses running again, but so far it hasn’t been enough to promote a lot of investment in new machines. The cost of a new press? Almost half a million dollars.
At least one manufacturer is optimistic about the future of vinyl. GZ Media, based in Czechoslovakia, is currently the world’s largest producer of vinyl records. President and owner Zdenek Pelc kept his record factory going during the lean years when vinyl sales bottomed out. He admits that the decision was not wholly logical; he continued in part because of an emotional attachment to the media. After demand for vinyl records practically disappeared, Pelc kept just a few of the presses running to meet the demand that remained. His intention was to be the last remaining manufacturer of vinyl records. Pelc’s emotional attachment to vinyl records seems to have served him well, and it’s a great example of why basing decisions on pure logic doesn’t always lead to the best results. Consumers make purchasing decisions in part based on the emotional appeal of the product, so it shouldn’t be surprising that consumers also feel an emotional attachment to vinyl records, as Pelc did.
When demand for vinyl records was low, Pelc stored the company’s presses that were no longer in use so that they could be cannibalized for parts as needed. When sales began to grow again in 2005, he started pulling old machines out of storage and even invested in a few new ones. This has made GZ Media not only the largest vinyl record producer in the world, but also one of the only ones with new factory equipment. GZ Media produces over 20 million vinyl records a year, and Pelc is excited to continue that trend and to remain a major manufacturer in what is currently still considered a niche market.
Critical Thinking Questions
- Why do you think vinyl records are appealing to customers?
- Do you think the sales growth will continue to be strong for vinyl sales? Why or why not?
- What research would you want to conduct prior to making a decision to invest in new presses?
Sources: Lee Barron, “Back on record – the reasons behind vinyl’s unlikely comeback,” The Conversation , April 17, 2015, https://theconversation.com/back-on-...comeback-39964 . Hannah Ellis-Peterson, “Record sales: vinyl hits 25-year high,” The Guardian, January 3, 2017, www.theguardian.com/music/20...tripsstreaming. Allan Kozinn, “Weaned on CDs, They’re Reaching for Vinyl,” The New York Times , June 9, 2013. Rick Lyman, “Czech company, pressing hits for years on vinyl, finds it has become one,” The New York Times, August 6, 2015. Alec Macfarlane and Chie Kobayashi, “Vinyl comeback: Sony to produce records again after 28-year break,” CNN Money , June 30, 2017, money.cnn.com/2017/06/30/news...rds/index.html. Kate Rogers, “Why millennials are buying more vinyl records,” CNBC.com, November 6, 2015. https://www.cnbc.com/2015/11/06/why-...l-records.html . Robert Tait, “In the groove: Czech firm tops list of world’s vinyl record producers,” The Guardian , August 18, 2016.


8.10.9A: Electrolytes and Electrolytic Solutions
Make sure you thoroughly understand the following essential ideas:
- Describe the properties of water that make it an ideal electrolytic solvent.
- Describe the general structure of ionic hydration shells.
- Explain why all cations act as acids in water.
- Describe some of the major ways in which the conduction of electricity through a solution differs from metallic conduction.
- Define resistance, resistivity, conductance, and conductivity.
- Define molar conductivity and explain its significance.
- Explain the major factors that cause molar conductivity to diminish as electrolyte concentrations increase.
- Describe the contrasting behavior of strong, intermediate, and weak electrolytes.
- Explain the distinction between ionic diffusion and ionic migration.
- Define the limiting ionic conductivity, and comment on some of its uses.
- Explain why hydrogen- and hydroxide ions exhibit exceptionally large ionic mobilities.
Electrolytic solutions are those that are capable of conducting an electric current. A substance that, when added to water, renders it conductive, is known as an electrolyte . A common example of an electrolyte is ordinary salt, sodium chloride. Solid NaCl and pure water are both non-conductive, but a solution of salt in water is readily conductive. A solution of sugar in water, by contrast, is incapable of conducting a current; sugar is therefore a non-electrolyte .
These facts have been known since 1800 when it was discovered that an electric current can decompose the water in an electrolytic solution into its elements (a process known as electrolysis ). By mid-century, Michael Faraday had made the first systematic study of electrolytic solutions. Faraday recognized that for a sample of matter to conduct electricity, two requirements must be met:
- The matter must be composed of, or contain, electrically charged particles.
- These particles must be mobile ; that is, they must be free to move under the influence of an external applied electric field.
In metallic solids, the charge carriers are electrons rather than ions; their mobility is a consequence of the quantum-mechanical uncertainty principle which promotes the escape of the electrons from the confines of their local atomic environment. In the case of electrolytic solutions, Faraday called the charge carrier ions (after the Greek word for "wanderer"). His most important finding was that each kind of ion (which he regarded as an electrically-charged atom) carries a definite amount of charge, most commonly in the range of ±1-3 units.
The fact that the smallest charges observed had magnitudes of ±1 unit suggested an "atomic" nature for electricity itself, and led in 1891 to the concept of the "electron" as the unit of electric charge — although the identification of this unit charge with the particle we now know as the electron was not made until 1897.
An ionic solid such as NaCl is composed of charged particles, but these are held so tightly in the crystal lattice that they are unable to move about, so the second requirement mentioned above is not met and solid salt is not a conductor. If the salt is melted or dissolved in water, the ions can move freely and the molten liquid or the solution becomes a conductor.
Since positively-charged ions are attracted to a negative electrode that is traditionally known as the cathode , these are often referred to as cations . Similarly, negatively-charged ions, being attracted to the positive electrode, or anode , are called anions . (These terms were all coined by Faraday.)
The role of the solvent: what's special about water
Although we tend to think of the solvent (usually water) as a purely passive medium within which ions drift around, it is important to understand that electrolytic solutions would not exist without the active involvement of the solvent in reducing the strong attractive forces that hold solid salts and molecules such as HCl together. Once the ions are released, they are stabilized by interactions with the solvent molecules. Water is not the only liquid capable of forming electrolytic solutions, but it is by far the most important. It is therefore essential to understand those properties of water that influence the stability of ions in aqueous solution.
According to Coulomb's law, the force between two charged particles is directly proportional to the product of the two charges, and inversely proportional to the square of the distance between them:
The proportionality constant D is the dimensionless dielectric constant . Its value in empty space is unity, but in other media it will be larger. Since D appears in the denominator, this means that the force between two charged particles within a gas or liquid will be less than if the particles were in a vacuum. Water has one of the highest dielectric constants of any known liquid; the exact value varies with the temperature, but 80 is a good round number to remember. When two oppositely-charged ions are immersed in water, the force acting between them is only 1/80 as great as it would be between the two gaseous ions at the same distance. It can be shown that in order to separate one mole of Na + and Cl – ions at their normal distance of 23.6 pm in solid sodium chloride, the work required will be 586 J in a vacuum, but only 7.3 J in water
Dielectric Constant
The dielectric constant is a bulk property of matter, rather than being a property of the molecule itself, as is the dipole moment. It is a cooperative effect of all the molecules in the liquid, and is a measure of the extent to which an applied electric field will cause the molecules to line up with the negative ends of their dipoles pointing toward the positive direction of the electric field. The high dielectric constant of water is a consequence of the small size of the H 2 O molecule in relation to its large dipole moment.
When one molecule is reoriented by the action of an external electric field, local hydrogen bonding tends to pull neighboring molecules into the same alignment, thus producing an additive effect that would be absent if the molecules were all acting independently.
Water's dipole moment stabilizes dissolved ions through hydrogen bonding
When an ion is introduced into a solvent, the attractive interactions between the solvent molecules must be disrupted to create space for the ion. This costs energy and would by itself tend to inhibit dissolution. However, if the solvent has a high permanent dipole moment, the energy cost is more than recouped by the ion-dipole attractions between the ion and the surrounding solvent molecules.
Water, as you know, has a sizeable dipole moment that is the source of the hydrogen bonding that holds the liquid together. The greater strength of ion-dipole attractions compared to hydrogen-bonding (dipole-dipole) attractions stabilizes the dissolved ion.
Water is not the only electrolytic solvent, but it is by far the best. For some purposes, chemists occasionally need to employ non-aqueous solvents when studying electrolytes. Here are a few examples:
| solvent | Melting Point (°C) | Boiling Point °C | D | dipole moment | specific conductivity, S/cm |
|---|---|---|---|---|---|
| water | 0 | 100 | 80.1 | 1.87 | 5.5 × 10 –8 |
| methanol | –98 | 64.7 | 32.7 | 1.7 | 1.5× 10 –7 |
| ethanol | –114 | 78.3 | 24.5 | 1.66 | 1.35 × 10 –9 |
| acetonitrile | –43.8 | 81.6 | 37.5 | 3.45 | 7 × 10 –6 |
| dimethyl sulfoxide | 18.5 | 189 | 46.7 | 3.96 | 3 × 10 –8 |
| ethylene carbonate | 36.4 | 238 | 89.6 | 4.87 | < 1 × 10 –9 |


Questions to consider:
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What do I need to know about student loans?
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How dangerous is debt?
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What should I think about when getting and using a credit card?
Yes, taking on too much debt can (and does) have disastrous effects on people’s personal finances, but if used appropriately, debt can be a tool to help you build wealth. Debt is like fire.
The Danger of Debt
When you take out a loan, you take on an obligation to pay the money back, with interest, through a monthly payment. You will take this debt with you when you apply for auto loans or home loans, when you enter into a marriage, and so on. Effectively, you have committed your future income to the loan. While this can be a good idea with student loans, take on too many loans and your future self will be poor, no matter how much money you make. Worse, you’ll be transferring more and more of your money to the bank through interest payments.
Compounding Interest
While compounding works to make you money when you are earning interest on savings or investments, it works against you when you are paying the interest on loans. To avoid compounding interest on loans, make sure your payments are at least enough to cover the interest charged each month. The good news is that the interest you are charged will be listed each month on the loan account statements you are sent by the bank or credit union, and fully amortized loans will always cover the interest costs plus enough principal to pay off what you owe by the end of the loan term.
The two most common loans on which people get stuck paying compounding interest are credit cards and student loans. Paying the minimum payment each month on a credit card will just barely cover the interest charged that month, while anything you buy with the credit card will begin to accrue interest on the day you make the purchase. Since credit cards charge interest daily, you’ll begin paying interest on the interest immediately, starting the compound interest snowball working against you. When you get a credit card, always pay the credit card balance down to $0 each month to avoid the compound interest trap.
Student loans are another way you can be caught in the compound interest trap. When you have an unsubsidized student loan or put your loans into deferment, the interest continues to rack up on the loans. Again, you’ll be charged interest on the interest, not just on the original loan amount, forcing you to pay compound interest on the loan.
Sacrificing Your Future Fun
When you graduate college, you are most likely to graduate with student loan debt and credit card debt.
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Many students use credit cards and student loans to allow them to pay for fun today, such as trips, clothing, and expensive meals.
Getting into debt while in college forces you to sacrifice your future fun. Say you take out $100,000 in student loans instead of the $50,000 you need, doubling your monthly payment. You are not just making an extra $338 payment; you are also sacrificing anything else you can do with that money. You sacrifice that extra $338 a month, every month, for the next twenty-five years. You can’t use it to go to the movies, pay down other debt, save for a home, take a vacation, or throw a party. When you sign those papers, you sacrifice all those opportunities every month for decades. As a result, when you take out a loan, you should make sure it’s a good loan.
How Much Good Debt to Take On
A drink of water is refreshing on a hot day and is required to stay alive. Too much water, however, and you will drown.
During college and for the first few years after graduation, most students should only have two loans: student loans and possibly a car loan. We’ve already discussed your student loans, which should be equal to or less than your first year’s expected salary after graduation.
When you get a car, you should keep your car payment to between 10 and 20 percent of your monthly take-home pay. This means if your paycheck is $200 per week, your car payment should be no more than $80–$160 each month.
In total, you want your debt payments (plus rent if you are renting) to be no more than 44 percent of your take-home pay. If you are planning to build wealth, however, you want to cap it at 30 percent of take-home pay.
Signs You Have Too Much Debt
You can consider yourself in too much debt if you have any of the following situations:
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You cannot make your minimum credit card payments.
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Your money is gone before your next paycheck.
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Bill collectors are contacting you.
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You are unable to get a loan.
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Your paycheck is being garnished by creditor.
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You are considering a debt consolidation loan with extra fees added.
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Your items are repossessed.
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You do not know your debt or financial situation.
Getting and Using a Credit Card
One of the most controversial aspects of personal finance is the use of credit cards. While credit cards can be an incredibly useful tool, their high interest rates, combined with the how easily credit cards can bury you in debt, make them extremely dangerous if not managed correctly.
Reflect on Elan from the chapter introduction and how he felt. How would you (or did you) feel to hold a new credit card with a $2,000 spending limit?
Benefits of a Credit Card
There are three main benefits of getting a credit card. The first is that credit cards offer a secure and convenient method of making purchases, similar to using a debit card. When you carry cash, you have the potential of having the money lost or stolen. A credit card or debit card, on the other hand, can be canceled and replaced at no cost to you.
Additionally, credit cards offer greater consumer protections than debit cards do. These consumer protections are written into law, and with credit cards you have a maximum liability of $50. With a debit card, you are responsible for transfers made up until the point you report the card stolen. In order to have the same protections as with credit cards, you need to report the card lost or stolen within 48 hours. The longer you wait to report the loss of the card, or the longer it takes you to realize you lost your card, the more money you may be responsible for, up to an unlimited amount.
12
The final benefit is that a credit card will allow you to build your credit score, which is helpful in many aspects of life. While most people associate a credit score with getting better rates on loans, credit scores are also important to getting a job, lowering car insurance rates, and finding an apartment.
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What Is a Good Credit Score?
Most credit scores have a 300–850 score range. The higher the score, the lower the risk to lenders. A “good” credit score is considered to be in the 670–739 score range.
Table 12.4
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Credit Score Ranges
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Rating
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Description
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< 580
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Poor
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This credit score is well below the average score of US consumers and demonstrates to lenders that the borrower may be a risk.
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580-669
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Fair
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This credit score is below the average score of US consumers, though many lenders will approve loans with this score.
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670-739
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Good
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This credit score is near or slightly above the average of US consumers, and most lenders consider this a good score.
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740-799
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Very Good
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This credit score is above the average of US consumers and demonstrates to lenders that the borrower is very dependable.
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800+
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Exceptional
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This credit score is well above the average score of US consumers and clearly demonstrates to lenders that the borrower is an exceptionally low risk.
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Components of a Credit Score and How to Improve Your Credit
Credit scores contain a total of five components. These components are credit payment history (35 percent), credit utilization (30 percent), length of credit history (15 percent), new credit (10 percent), and credit mix (10 percent). The main action you can take to improve your credit score is to stop charging and pay all bills on time. Even if you cannot pay the full amount of the credit card balance, which is the best practice, pay the minimum on time. Paying more is better for your debt load but does not improve your score. Carrying a balance on a credit card does not improve your score. Your score will go down if you pay bills late and owe more than 30 percent of your credit available. Your credit score is a reflection of your willingness and ability to do what you say you will do—pay your debts on time.
How to Use a Credit Card
All the benefits of credit cards are destroyed if you carry credit card debt. Credit cards should be used as a method of paying for things you can afford, meaning you should only use a credit card if the money is already sitting in your bank account and is budgeted for the item you are buying. If you use credit cards as a loan, you are losing the game.
Every month, you should pay your credit card off in full, meaning you will be bringing the loan amount down to $0.  If you do this, you won’t pay any interest on the credit card.
 If you are even one cent short on the payment, meaning you pay $432.55 instead, you must pay daily interest on the entire amount from the date you made the purchases. Your credit card company, of course, will be perfectly happy for you to make smaller payments—that’s how they make money. It is not uncommon for people to pay twice as much as the amount purchased and take years to pay off a credit card when they only pay the minimum payment each month.
 Start by narrowing the hundreds of card options to the few with the lowest APR (annual percentage rate).
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Avoid Cards with Annual Fees or Minimum Usage Requirements
Your first credit card should ideally be one you can keep forever, but that’s expensive to do if they charge you an annual fee or have other requirements just for having the card. There are many options that won’t require you to spend a minimum amount each month and won’t charge you an annual fee.
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Keep the Credit Limit Equal to Two Weeks’ Take-Home Pay
Even though you want to pay your credit card off in full, most people will max out their credit cards once or twice while they are building their good financial habits. If this happens to you, having a small credit limit makes that mistake a small mistake instead of a $5,000 mistake.
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Avoid Rewards Cards
Everyone loves to talk about rewards cards, but credit card companies wouldn’t offer rewards if they didn’t earn them a profit. Rewards systems with credit cards are designed by experts to get you to spend more money and pay more interest than you otherwise would. Until you build a strong habit of paying off your card in full each month, don’t step into their trap.


4: Dynamics- Force and Newton's Laws of Motion
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- 4.4: Newton’s Third Law of Motion- Symmetry in Forces
- There is a passage in the musical Man of la Mancha that relates to Newton’s third law of motion.  This is exactly what happens whenever one body exerts a force on another—the first also experiences a force (equal in magnitude and
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- 4.5: Normal, Tension, and Other Examples of Forces
- Forces are given many names, such as push, pull, thrust, lift, weight, friction, and tension. Traditionally, forces have been grouped into several categories and given names relating to their source, how they are transmitted, or their effects. The most important of these categories are discussed in this section, together with some interesting applications. Further examples of forces are discussed later in this text.
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- 4.6: Problem-Solving Strategies
- Success in problem solving is obviously necessary to understand and apply physical principles, not to mention the more immediate need of passing exams. The basics of problem solving, presented earlier in this text, are followed here, but specific strategies useful in applying Newton’s laws of motion are emphasized. These techniques also reinforce concepts that are useful in many other areas of physics. Many problem-solving strategies are stated outright in the worked examples.
Thumbnail: For every action there is a reaction. (CC BY-SA 3.0; Benjamin Crowell )


5.3: Factor Theorem and Remainder Theorem
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In the last section, we limited ourselves to finding the intercepts, or zeros, of polynomials that factored simply, or we turned to technology. In this section, we will look at algebraic techniques for finding the zeros of polynomials like \(h(t)=t^{3} +4t^{2} +t-6\).
Long Division
In the last section we saw that we could write a polynomial as a product of factors, each corresponding to a horizontal intercept. If we knew that \(x = 2\) was an intercept of the polynomial \(x^3 + 4x^2 - 5x - 14\), we might guess that the polynomial could be factored as \(x^{3} +4x^{2} -5x-14=(x-2)\) (something). To find that "something," we can use polynomial division.
Example \(\PageIndex{1}\)
Divide \(x^{3} +4x^{2} -5x-14\) by \(x-2\).
Solution
Start by writing the problem out in long division form
Now we divide the leading terms: \(x^{3} \div x=x^{2}\). It is best to align it above the same-powered term in the dividend. Now, multiply that \(x^{2}\) by \(x-2\) and write the result below the dividend.
Again, divide the leading term of the remainder by the leading term of the divisor. \(6x^{2} \div x=6x\). We add this to the result, multiply 6 x by \(x-2\), and subtract.
This tells us \(x^{3} +4x^{2} -5x-14\) divided by \(x-2\) is \(x^{2} +6x+7\), with a remainder of zero. This also means that we can factor \(x^{3} +4x^{2} -5x-14\) as \(\left(x-2\right)\left(x^{2} +6x+7\right)\).
This gives us a way to find the intercepts of this polynomial.
Example \(\PageIndex{2}\)
Find the horizontal intercepts of \(h(x)=x^{3} +4x^{2} -5x-14\).
Solution
To find the horizontal intercepts, we need to solve \(h(x) = 0\). From the previous example, we know the function can be factored as \(h(x)=\left(x-2\right)\left(x^{2} +6x+7\right)\).
\(h(x)=\left(x-2\right)\left(x^{2} +6x+7\right)=0\) when \(x = 2\) or when \(x^{2} +6x+7=0\). This doesn’t factor nicely, but we could use the quadratic formula to find the remaining two zeros.
\[x=\dfrac{-6\pm \sqrt{6^{2} -4(1)(7)} }{2(1)} =-3\pm \sqrt{2} \nonumber \]
The horizontal intercepts will be at \((2,0)\), \(\left(-3-\sqrt{2} ,0\right)\), and \(\left(-3+\sqrt{2} ,0\right)\).
Exercise \(\PageIndex{1}\)
Divide \(2x^{3} -7x+3\) by \(x+3\) using long division.
- Answer
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The Factor and Remainder Theorems
When we divide a polynomial, \(p(x)\) by some divisor polynomial \(d(x)\), we will get a quotient polynomial \(q(x)\) and possibly a remainder \(r(x)\). In other words,
\[p(x)=d(x)q(x)+r(x)\]
Because of the division, the remainder will either be zero, or a polynomial of lower degree than d(x). Because of this, if we divide a polynomial by a term of the form \(x-c\), then the remainder will be zero or a constant.
If \(p(x)=(x-c)q(x)+r\), then \(p(c)=(c-c)q(c)+r=0+r=r\), which establishes the Remainder Theorem.
The Remainder Theorem
If \(p(x)\) is a polynomial of degree 1 or greater and c is a real number, then when p(x) is divided by \(x-c\), the remainder is \(p(c)\).
If \(x-c\) is a factor of the polynomial \(p\), then \(p(x)=(x-c)q(x)\) for some polynomial \(q\). Then \(p(c)=(c-c)q(c)=0\), showing \(c\) is a zero of the polynomial. This shouldn’t surprise us - we already knew that if the polynomial factors it reveals the roots.
If \(p(c)=0\), then the remainder theorem tells us that if p is divided by \(x-c\), then the remainder will be zero, which means \(x-c\) is a factor of \(p\).
the factor theorem
If \(p(x)\) is a nonzero polynomial, then the real number \(c\) is a zero of \(p(x)\) if and only if \(x-c\) is a factor of \(p(x)\).
Synthetic Division
Since dividing by \(x-c\) is a way to check if a number is a zero of the polynomial, it would be nice to have a faster way to divide by \(x-c\) than having to use long division every time. Happily, quicker ways have been discovered.
Let’s look back at the long division we did in Example 1 and try to streamline it. First, let’s change all the subtractions into additions by distributing through the negatives.
Next, observe that the terms \(-x^{3}\), \(-6x^{2}\), and \(-7x\) are the exact opposite of the terms above them. The algorithm we use ensures this is always the case, so we can omit them without losing any information. Also note that the terms we ‘bring down’ (namely the \(\mathrm{-}\)5x and \(\mathrm{-}\)14) aren’t really necessary to recopy, so we omit them, too.
Now, let’s move things up a bit and, for reasons which will become clear in a moment, copy the \(x^{3}\) into the last row.
Note that by arranging things in this manner, each term in the last row is obtained by adding the two terms above it. Notice also that the quotient polynomial can be obtained by dividing each of the first three terms in the last row by \(x\) and adding the results. If you take the time to work back through the original division problem, you will find that this is exactly the way we determined the quotient polynomial.
This means that we no longer need to write the quotient polynomial down, nor the \(x\) in the divisor, to determine our answer.
We’ve streamlined things quite a bit so far, but we can still do more. Let’s take a moment to remind ourselves where the \(2x^{2}\), \(12x\) and 14 came from in the second row. Each of these terms was obtained by multiplying the terms in the quotient, \(x^{2}\), 6x and 7, respectively, by the -2 in \(x - 2\), then by -1 when we changed the subtraction to addition. Multiplying by -2 then by -1 is the same as multiplying by 2, so we replace the -2 in the divisor by 2. Furthermore, the coefficients of the quotient polynomial match the coefficients of the first three terms in the last row, so we now take the plunge and write only the coefficients of the terms to get
We have constructed a synthetic division tableau for this polynomial division problem. Let’s re-work our division problem using this tableau to see how it greatly streamlines the division process. To divide \(x^{3} +4x^{2} -5x-14\) by \(x-2\), we write 2 in the place of the divisor and the coefficients of \(x^{3} +4x^{2} -5x-14\)in for the dividend. Then "bring down" the first coefficient of the dividend.
Next, take the 2 from the divisor and multiply by the 1 that was "brought down" to get 2. Write this underneath the 4, then add to get 6.
Now take the 2 from the divisor times the 6 to get 12, and add it to the -5 to get 7.
Finally, take the 2 in the divisor times the 7 to get 14, and add it to the -14 to get 0.
The first three numbers in the last row of our tableau are the coefficients of the quotient polynomial. Remember, we started with a third degree polynomial and divided by a first degree polynomial, so the quotient is a second degree polynomial. Hence the quotient is \(x^{2} +6x+7\). The number in the box is the remainder. Synthetic division is our tool of choice for dividing polynomials by divisors of the form \(x - c\). It is important to note that it works only for these kinds of divisors. Also take note that when a polynomial (of degree at least 1) is divided by \(x - c\), the result will be a polynomial of exactly one less degree. Finally, it is worth the time to trace each step in synthetic division back to its corresponding step in long division.
Example \(\PageIndex{3}\)
Use synthetic division to divide \(5x^{3} -2x^{2} +1\) by \(x-3\).
Solution
When setting up the synthetic division tableau, we need to enter 0 for the coefficient of \(x\) in the dividend. Doing so gives
Since the dividend was a third degree polynomial, the quotient is a quadratic polynomial with coefficients 5, 13 and 39. Our quotient is \(q(x)=5x^{2} +13x+39\) and the remainder is \(r(x) = 118\). This means
\[5x^{3} -2x^{2} +1=(x-3)(5x^{2} +13x+39)+118\nonumber \]
It also means that \(x-3\) is not a factor of \(5x^{3} -2x^{2} +1\).
Example \(\PageIndex{4}\)
Divide \(x^{3} +8\) by \(x+2\).
Solution
For this division, we rewrite \(x+2\) as \(x-\left(-2\right)\) and proceed as before.
The quotient is \(x^{2} -2x+4\) and the remainder is zero. Since the remainder is zero, \(x+2\) is a factor of \(x^{3} +8\).
\[x^{3} +8=(x+2)\left(x^{2} -2x+4\right)\nonumber \]
Exercise \(\PageIndex{2}\)
Divide \(4x^{4} -8x^{2} -5x\) by \(x-3\) using synthetic division.
- Answer
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\(4x^4 - 8x^2 - 5x\) divided by \(x -3\) is \(4x^3 + 12x^2 + 28x + 79\) with remainder 237
Using this process allows us to find the real zeros of polynomials, presuming we can figure out at least one root. We’ll explore how to do that in the next section.
Example \(\PageIndex{5}\)
The polynomial \(p(x)=4x^{4} -4x^{3} -11x^{2} +12x-3\) has a horizontal intercept at \(x=\dfrac{1}{2}\) with multiplicity 2. Find the other intercepts of \(p(x)\).
Solution
Since \(x=\dfrac{1}{2}\) is an intercept with multiplicity 2, then \(x-\dfrac{1}{2}\) is a factor twice. Use synthetic division to divide by \(x-\dfrac{1}{2}\) twice.
From the first division, we get \(4x^{4} -4x^{3} -11x^{2} +12x-3=\left(x-\dfrac{1}{2} \right)\left(4x^{3} -2x^{2} -x-6\right)\) The second division tells us
\[4x^{4} -4x^{3} -11x^{2} +12x-3=\left(x-\dfrac{1}{2} \right)\left(x-\dfrac{1}{2} \right)\left(4x^{2} -12\right)\nonumber \]
To find the remaining intercepts, we set \(4x^{2} -12=0\) and get \(x=\pm \sqrt{3}\).
Note this also means \(4x^{4} -4x^{3} -11x^{2} +12x-3=4\left(x-\dfrac{1}{2} \right)\left(x-\dfrac{1}{2} \right)\left(x-\sqrt{3} \right)\left(x+\sqrt{3} \right)\).
Important Topics of this Section
- Long division of polynomials
- Remainder Theorem
- Factor Theorem
- Synthetic division of polynomials


1.7: Enzyme Function
In every living cell, many chemical reactions are performed. In chemical reactions, the reactants are molecules that undergo a change, which results in the products . The arrow indicates the direction of the reaction as the reactants proceed to be transformed into the product(s). As you can see in the figure below, the number of reactants and products can vary, but the number of atoms is the same on both sides of the arrow. During synthesis reactions (Example 1), the reactants are joined to form a product. During decomposition reactions (Example 2), the reactant is broken down into products. During exchange reactions (Example 3) both decomposition and synthesis take place. The decomposition of two reactants is followed by an exchange and synthesis of two new compounds from them.
Example 1 (Synthesis Reaction): \(\ce{A + B → AB}\)
\[\ce{2H2 + O2 → 2 H2O}\]
Example 2 (Decomposition Reaction): \(\ce{AB → A + B}\)
\[\ce{2H2O → 2 H2 + O2}\]
Example 3 (Exchange Reaction): \(\ce{A + BC → AC + B}\)
\[\ce{2 Na + 2 H2O → 2 NaOH + H2}\]
Enzymes are very efficient catalysts for biochemical reactions. These catalysts speed up reactions by providing an alternative reaction pathway that requires a lower activation energy needed for a reaction to get started. The lower the activation energy for a reaction, the faster the rate at which it will proceed. Enzymes only lower the activation energy, but do not change the difference in energy levels between the reactants and the products. They work by binding to the reactants and converting them to a different compound (the product). Enzymes are specific to a type of reactant, and therefore can catalyze only one type of reaction. This enzyme specificity is the result of the particular shape of the enzyme that only permits binding to one type of reactant, much like a key fits into a lock (Figure 2). The reactants in an enzymatic chemical reaction are called substrates . Notice how the shape of the enzyme fits its substrate. The location where the enzyme binds a substrate is called the active site because the reaction occurs here. At the end of the reaction, the product is released, and the enzyme can then bind to more substrate. Thus, an enzyme can perform the reaction over and over again, as long as the substrate is present.
Most enzymes are complex proteins that function most efficiently within a specific range of temperature and pH. Extremes in temperature or pH will denature the enzyme by permanently altering its chemical structure. Even a small change in the protein’s structure will change the enzyme’s shape enough to prevent the substrate from binding, and thus keep the reaction from occurring. In this laboratory, you will demonstrate how altering the temperature, enzyme concentration, and pH will affect an enzyme’s ability to function. Specifically, you will be studying the actions of the enzyme catalase .
Exercise 1: Catalase Activity
Materials:
- Water (distilled or deionized)
- Disposable pipets
- Catalase (400 units/mL solution)
- Hydrogen peroxide (3% solution)
- Sucrose solution (5% solution)
- Small test tubes (10 ml test tubes) for Exercises 1, 2, and 4
- Large test tubes (20 ml test tubes) for Exercise 3
- Ruler
- Wax pencil / Sharpie
- Ice
- Boiling water bath
- Refrigerator
- Incubator (37o Celsius)
- 0.1 M HCl
- 0.1 M NaOH
- Buffer pH 7.0
- Safety glasses
Catalase is an enzyme that speeds up the breakdown of hydrogen peroxide to water and oxygen:
Hydrogen peroxide → water + oxygen gas
\[\ce{2 H2O2 → 2 H2O + O2}\]
- What is the reactant in this reaction? _______________________________
- What is the substrate for catalase? ________________________________
- What are the products for this reaction? _____________________________
- Bubbling occurs as the reaction proceeds. Explain why. _____________________________________________________________
Procedure:
- With a wax pencil (or Sharpie), label three small test tubes (#1, #2, #3).
- Using the ruler, mark each tube at the 1 cm (first mark) and 5 cm (second mark) levels from the bottom of the tube.
- Fill tube #1 to the first mark with catalase. Then fill it to the second mark with hydrogen peroxide.
- Swirl the contents to mix and wait at least 20 seconds for bubbles to develop.
- Using the ruler, measure the height of the bubble column (in millimeters), and record your results in Table 1 below.
- Fill tube #2 to the first mark with water. Then fill it to the second mark with hydrogen peroxide.
- Swirl the contents to mix and wait at least 20 seconds for bubbles to develop.
- Using the ruler, measure the height of the bubble column (in millimeters), and record your results in Table 1 below.
- Fill tube #3 to the first mark with catalase. Then fill to the second mark with sucrose solution.
- Swirl the contents to mix and wait at least 20 seconds for bubbles to develop.
- Using the ruler, measure the height of the bubble column (in millimeters), and record your results in Table 1 below.
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Tube |
Contents |
Bubble Column Height (mm) |
|---|---|---|
|
1 |
catalase, hydrogen peroxide |
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2 |
water, hydrogen peroxide |
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3 |
catalase, sucrose solution |
- Which tube showed the most bubbling? Explain why. ________________________________________________________________
________________________________________________________________
- Which tube was the negative control? __________________________________
- Which tube was the positive control? __________________________________
- Describe what you observe in test tube #3. What was the purpose of this tube? ________________________________________________________________
________________________________________________________________
Exercise 2: Effect of Temperature on Enzyme Activity
In general, cold temperatures slow chemical reactions, and warm temperatures speed up chemical reactions. Every enzyme, however, has an optimal temperature at which it works best. Some enzymes prefer cooler temperatures, and others prefer warm temperatures. However, extreme increases in temperature (i.e. boiling) will denature enzymes, making them inactive.
In the following exercise, you will test enzyme function at four different temperatures (on ice, in a refrigerator, in a warm incubator, and in a boiling water bath). Before setting up this experiment, formulate a hypothesis regarding the effect on enzyme activity. For example, do you think the enzyme will perform better at a warmer temperature? A cooler temperature? On ice? At boiling temperatures?
Employing Steps in the Scientific Method:
- Record the Question that is being investigated in this experiment. ________________________________________________________________
- Record a Hypothesis for the question stated above. ________________________________________________________________
- Predict the results of the experiment based on your hypothesis (if/then). ________________________________________________________________
- Perform the experiment below and collect your data.
Procedure:
- With a wax pencil (or Sharpie), label four small test tubes (#1, #2, #3, #4) and mark each at the 1 cm and 5 cm levels.
- Fill each tube to the first mark with catalase.
- Place tube #1 on ice, tube #2 at room temperature, tube #3 in a 37 degree Celsius incubator or warm water bath, and tube #4 in a boiling water bath or heat block. Wait 15 minutes.
- While you are waiting, use a thermometer to measure the temperature of the environment for all four tubes. Record the values in Table 2 below.
- After the 15-minute incubation, fill each tube to the second mark with hydrogen peroxide.
- Swirl the contents to mix and wait 20 seconds.
- Measure the height of the bubble column (in mm) for each tube and record your results in Table 2 below.
|
Tube |
Temperature (oC) |
Bubble Column Height (mm) |
|---|---|---|
|
1 - on ice |
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2 - room temperature |
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3 - warm water bath |
||
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4 - boiling |
- Which tube showed the most enzyme activity? Explain. ________________________________________________________________
- What is the optimal temperature for catalase activity? Explain ________________________________________________________________
- Was your hypothesis supported? ________________________________________________________________
- What is your conclusion concerning the effect of temperature on enzyme activity? ________________________________________________________________
- What is the optimal temperature for enzymes in the human body? ________________________________________________________________
- What effect could a fever have on enzymatic activity in the human body? ________________________________________________________________
Extension Activity: (Optional)
The results of this experiment can be presented graphically. The presentation of your data in a graph will assist you in interpreting your results. Based on your results, you can complete the final step of scientific investigation, in which you must be able to propose a logical argument that either allows you to support or reject your initial hypothesis.
- Graph your results using the data from Table 2.
- What is the dependent variable? Which axis is used to graph this data? ______________________________________________________________________
- What is your independent variable? Which axis is used to graph this data? ______________________________________________________________________
Exercise 3: Effect of Concentration on Enzyme Activity
In general, the amount of product produced in a given amount of time should increase if you increase the enzyme concentration.
Employing Steps in the Scientific Method:
- Record the Question that is being investigated in this experiment. ________________________________________________________________
- Record a Hypothesis for the question stated above. ________________________________________________________________
- Predict the results of the experiment based on your hypothesis (if/then). ________________________________________________________________
- Perform the experiment below and collect your data.
Procedure:
- With a wax pencil (or Sharpie), label three large test tubes (#1, #2, #3). Make sure to use the larger tubes provided by your instructor.
- Mark tube #1 at the 1 cm and 5 cm levels.
- Fill to the first mark with catalase and to the second mark with hydrogen peroxide.
- Swirl the contents to mix and wait 10 seconds.
- Measure the height of the bubble column (in mm) and record your results in Table 3 below.
- Mark tube #2 at the 2 cm and 6 cm levels.
- Fill to the first mark with catalase and to the second mark with hydrogen peroxide.
- Swirl the contents to mix and wait 10 seconds.
- Measure the height of the bubble column (in mm) and record your results in Table 3 below.
- Mark tube #3 at the 3 cm and 7 cm levels.
- Fill to the first mark with catalase and to the second mark with hydrogen peroxide.
- Swirl the contents to mix and wait 10 seconds.
- Measure the height of the bubble column (in mm) and record your results in Table 3.
|
Tube |
Amount of Enzyme |
Bubble Column Height (in mm) |
|---|---|---|
|
1 |
1 cm |
|
|
2 |
2 cm |
|
|
3 |
3 cm |
- The amount of bubbling corresponds to the degree of enzyme activity. Which tube showed the most activity. Explain. ________________________________________________________________
________________________________________________________________
- If we waited for an unlimited amount of time, would the results be the same in all tubes? Explain. ________________________________________________________________
________________________________________________________________
- In this experiment, was the amount of substrate the same in all three tubes? ________________________________________________________________
- Generate a hypothesis about what you might observe if the amount of substrate concentration were increased while the enzyme concentration remained the same. Explain. ________________________________________________________________
________________________________________________________________
Extension Activity: (Optional)
The results of this experiment can be presented graphically. The presentation of your data in a graph will assist you in interpreting your results. Based on your results, you can complete the final step of scientific investigation, in which you must be able to propose a logical argument that either allows you to support or reject your initial hypothesis.
- Graph your results using the data from Table 3.
- What is the dependent variable? Which axis is used to graph this data? ______________________________________________________________________
- What is your independent variable? Which axis is used to graph this data? ______________________________________________________________________
Exercise 4: Effect of pH on Enzyme Activity
Each enzyme has an optimal pH, or level of acidity or alkalinity at which it functions best. A higher or lower pH affects hydrogen bonding and can alter the structure of the enzyme, leading to reduced activity.
Employing Steps in the Scientific Method:
- Record the Question that is being investigated in this experiment. ________________________________________________________________
- Record a Hypothesis for the question stated above. ________________________________________________________________
- Predict the results of the experiment based on your hypothesis (if/then). ________________________________________________________________
- Perform the experiment below and collect your data.
Procedure:
- With a wax pencil (or Sharpie), label three small test tubes (#1, #2, #3) and mark at the 1 cm, 2 cm, and 6 cm levels. Fill each tube to the 1 cm level with catalase.
- Fill tube #1 to the second mark with 0.1 M HCl.
- Fill tube #2 to the second mark with buffer (pH 7.0).
- Fill tube #3 to the second mark with 0.1 M NaOH.
- Carefully swirl to mix and wait 20 seconds.
- Fill all three tubes to the third mark with hydrogen peroxide.
- Carefully swirl to mix and wait 20 seconds.
- Measure the height of the bubble column (in mm) for each tube and record your results in Table 4 below.
|
Tube |
Acid / Buffer / Base |
Bubble Column Height (in mm) |
|---|---|---|
|
1 |
0.1 M HCl |
|
|
2 |
Buffer pH 7.0 |
|
|
3 |
0.1 M NaOH |
- Which tube showed the most activity? ________________________________________________________________
- What is the optimal pH for catalase? ________________________________________________________________
Questions for Review
- What is the function of an enzyme? What specific monomers (i.e. building blocks) make up enzymes?
- What does it mean when an enzyme becomes denatured ?
Describe at least 2 ways in which an enzyme can become denatured.
3. What types of bonds or interactions are broken when an enzyme becomes denatured (name at least 3)?
4. Explain the difference between substrate and active site .
5. If an enzyme functions well at a pH of 4, would you expect it to also work well at a pH of 7? Explain.
Practical Challenge
- Eggs can contain bacteria such as Salmonella . Considering what you’ve learned in this laboratory exercise, explain how cooking eggs makes them safe to eat.
- What can happen to an enzyme when the pH of the environment becomes too acidic or too alkaline? Use your observations from the lab to support your answer .
- If you don’t want a cut potato to get brown, what could you do to prevent it assuming that the ‘browning’ occurs because of an enzymatic reaction? Explain your answer.
- What would happen to enzyme activity if the pH of your blood decreased (became more acidic) or increased (became more basic)? Explain.
References
Belwood, Jacqueline; Rogers, Brandy; and Christian, Jason, Foundations of Biology Lab Manual (Georgia Highlands College). “Lab 5: Enzyme Function,” (2019). Biological Sciences Open Textbooks . 18. CC-BY https://oer.galileo.usg.edu/biology-textbooks/18


9.5: Monte Carlo Integration
The final numerical integration scheme that we'll discuss is Monte Carlo integration , and it is conceptually completely different from the previous schemes. Instead of assigning a set of discretization points (either explicitly, as in the mid-point/trapezium/Simpson's rules, or through a machine optimization procedure, as in the adaptive quadrature method), this method randomly samples the points in the integration domain. If the sampling points are independent and there is a sufficiently large number of them, the integral can be estimated by taking a weighted average of the integrand over the sampling points.
To be precise, consider a 1D integral over a domain \(x \in [a,b]\). Let each sampling point be drawn independently from a distribution \(p(x)\). This means that the probability of drawing sample \(x_{n}\) in the range \(x_n \in [x, x + dx]\) is \(p(x) dx\). The distribution is normalized, so that
\[\int_a^b p(x) \; dx = 1.\]
Let us take \(N\) samples, and evaluate the integrand at those points: this gives us a set of numbers \(\{f(x_n)\}\). We then compute the quantity
\[\mathcal{I}^{\mathrm{mc}} = \frac{1}{N} \sum_{n=0}^{N-1} \frac{f(x_n)}{p(x_n)}.\]
Unlike the estimators that we have previously studied, \(\mathcal{I}^{\mathrm{mc}}\) is a random number (because the underlying variables \(\{x_n\}\) are all random). Crucially, its average value is equal to the desired integral:
\[\begin{align} \left\langle\mathcal{I}^{\mathrm{mc}}\right\rangle &= \frac{1}{N} \sum_{n=0}^{N-1} \left\langle \frac{f(x_n)}{p(x_n)}\right\rangle \\ & = \left\langle \frac{f(x_n)}{p(x_n)}\right\rangle \qquad\mathrm{for}\;\mathrm{each}\; n \\ & = \int_a^b p(x) \, \left[\frac{f(x)}{p(x)}\right]\, dx \\ & = \int_a^b f(x)\, dx \end{align}\]
For low-dimensional integrals, there is normally no reason to use the Monte Carlo integration method. It requires a much larger number of samples in order to reach a level of numerical accuracy comparable to the other numerical integration methods. (For 1D integrals, Monte Carlo integration typically requires millions of samples, whereas Simpson's rule only requires hundreds or thousands of discretization points.) However, Monte Carlo integration outperforms discretization-based integration schemes when the dimensionality of the integration becomes extremely large. Such integrals occur, for example, in quantum mechanical calculations involving many-body systems, where the dimensionality of the Hilbert space scales exponentially with the number of particles.


5.4: Diversity, Equity, and Inclusion
By the end of this section, you will be able to:
- Define important considerations related to providing equal, diverse, and inclusive nursing care
- Identify factors that can prevent diversity and inclusion
- Explain how barriers to communication affect diversity and inclusion
Diversity and inclusion create an environment that encourages different ideas, cultures, backgrounds, and experiences. This type of environment allows nurses to provide more comprehensive and effective care to their patients. Diversity, equality, and inclusion foster a culture of mutual respect, understanding, and support which can lead to improved patient outcomes. Additionally, diversity and inclusion can help to reduce health disparities which can improve healthcare access and quality for communities that are traditionally underserved. Ultimately, diversity and inclusion are critical components of successful nursing practice that can help to ensure that all patients receive the best possible care.
Equality
The principle of ensuring that all individuals, regardless of their background or socioeconomic status, have equal access to healthcare resources and opportunities is called health equality (CDC, 2022b). When everyone has a fair opportunity to obtain optimal health, health equity is achieved (CDC, 2022a). Both equity and equality are important considerations when providing inclusive nursing care (Figure 5.7).
A standard linked to fairness for all in society is justice , a principle and moral obligation to act on the basis of equality and equity. The ANA states this obligation guarantees not only basic rights (respect, human dignity, autonomy, security, and safety) but also fairness in all operations of societal structures. This includes care being delivered with fairness, rightness, correctness, unbiasedness, and inclusiveness while being based on well-founded reason and evidence.
The CDC (2022a) discusses diversity and inclusion as important factors in health equity considerations. Diversity refers to the existence of societies, communities, or subcultures that differ substantially from one another. Cultural competence means respecting and appreciating these similarities and differences. Inclusion is the practice of creating an environment in which individuals of all backgrounds feel respected, valued, and supported (CDC, 2022b). There are numerous factors that can prevent diversity, inclusion, and justice. These can in turn create health disparities that limit access to care and decrease outcomes for certain groups.
Race/Ethnic Heritage
Race is a socially constructed idea because there are no true scientifically or biologically distinct races. Humans are not biologically different from each other. However, race and ethnicity have an undeniable effect on healthcare access and outcomes. In racism , it is presumed that races are distinct from one another and that there is a hierarchy to race, implying that races are unequal. As healthcare providers, nurses have an obligation to recognize the impact of racism on their patients and the communities they serve. In the United States, race and ethnic background have long played a role in health disparities among different populations.
Most underrepresented populations experience higher rates of chronic disease and premature death compared to the rates among White populations; however, some individuals from underrepresented groups, such as Asian and Hispanic immigrants, experience lower rates (National Academies of Sciences, Engineering, and Medicine, 2017a). American Indian, Alaska Native, and Black populations experience the highest infant mortality rates, while Asian and Pacific Islander populations experience the lowest (Figure 5.8). Black people are more likely than White people to die prematurely from heart disease, and Black men are twice as likely as White men to die prematurely from stroke.
Implicit bias related to race and ethnicity has been repeatedly shown in research to negatively affect patient care and outcomes. Nurses should also be sensitive to the fact that individuals from certain ethnicities may be distrusting of healthcare professionals due to cultural history and other factors.
Religion
Throughout human history, spirituality and health have often gone hand-in-hand. In many healing traditions, healers also serve as religious leaders (Figure 5.9). Many people consult and rely on their religious and spiritual beliefs when making medical decisions. For instance, Jehovah’s Witnesses do not accept whole blood, plasma, and platelets because they believe that this might interfere with eternal salvation; they believe it is against God’s will to accept blood products and will therefore not allow blood transfusions. A person’s religious beliefs can affect their diet, what medications they will take, and approaches to death and dying. Healthcare providers must be prepared to take patients’ religious and spiritual preferences into account as an important part of the treatment plan (Swihart et al., 2022). A thorough cultural assessment should include information on a patient’s religious or spiritual beliefs that might affect their care.
Age
Older adults struggle with some limitations in their care related to their age. Studies have shown that healthcare providers are more likely to assume that older patients’ conditions, such as cognitive decline, are due to their age and to deny them certain treatments as compared to younger patients (Hughes et al., 2020). Older patients also tend to be undertreated for pain and depression. Older adults are more likely to live in poverty and have limited access to transportation, which can make it difficult to get to medical appointments.
  To the extent that a person’s gender identity does not conform with the sex assigned to them at birth, they may identify as transgender or as gender nonbinary. The term transgender refers to someone whose gender identity or expression differs from traditional cultural gender roles for one’s sex assigned at birth. Transgender people, like cisgender people, may be sexually oriented toward men, women, both sexes, or neither sex. Gender expression refers to a person’s outward demonstration of gender in relation to societal norms, such as in style of dress, hairstyle, or other mannerisms. Sharing pronouns as part of a basic introduction to a patient can assist a transgender patient to feel secure sharing their pronouns in a healthcare setting. Asking a patient for their pronoun (he, she, they, ze) is considered part of a nursing assessment.
There is a strong body of research showing a history of gender bias in health care (Hughes et al., 2020). Providers are more likely to believe that the health complaints of women result from emotional instead of physical causes compared to men. There is also a demonstrated history of underdiagnosis and undertreatment of cardiovascular disease in women when compared to men.
 Sexual orientation is on a continuum and is manifested in one’s self-identity and behaviors.  (The “+” is sometimes added after LGBTQIA+ to capture additional orientations.) Historically, individuals within the LGBTQIA+ community have experienced discrimination and prejudice from healthcare providers and avoided or delayed health care due to these negative experiences. Despite increased recognition of this group of people in recent years, members of the LGBTQIA+ community continue to experience significant health disparities.
Disability
Disabilities can be present from birth or acquired later in life. They can be physical, cognitive, or mental health related. Adults with disabilities are more likely than adults with no disabilities to report poor health, including higher rates of obesity, diabetes, smoking, lack of physical activity, and cardiovascular disease. Adults with disabilities are also more likely to live in poverty, and even those with health insurance are less likely than adults without disabilities to seek care. Adults with disabilities also cite common stereotypes, bias, and beliefs among providers as barriers to care (VanPuymbrouck et al., 2020). Examples include lack of appropriate equipment to transfer disabled patients in doctor’s offices, or a healthcare provider’s assumption that the patient is unhealthy or fragile simply because they are disabled.
Education Level
Differences in educational levels can affect how people access healthcare services and understand health information to make informed decisions. The higher a person’s level of education, the higher is their life expectancy and the more likely they are to access preventative and screening services (Viinikainen et al., 2022). People with lower education levels are more likely to have higher weight and to engage in risky activities such as smoking and heavy drinking (Viinikainen et al., 2022). In the United States, the health disparities between the most educated and least educated people have been increasing over the last forty years, leading to an increasing discrepancy in morbidity and mortality rates among these groups (Viinikainen et al., 2022).
Physical Characteristics
Certain physical characteristics have the potential to create barriers to care. Patients who are deaf or blind may need accommodations to ensure that communication is clear and accurate. American Sign Language interpreters can be sought for patients who are deaf. Educational materials and consent forms printed in Braille can assist blind populations.
Socioeconomic Status
In the United States, socioeconomic status is a major determinant of health status. Individuals from low socioeconomic groups, including those experiencing homelessness or living in poverty, are prone to higher rates of diseases like heart disease, diabetes, stroke, and obesity (Baggett et al., 2013; Fazel et al., 2014; National Academies of Sciences, Engineering, and Medicine, 2017b). This is attributed to their limited opportunities for early prevention and a lack of resources to adhere to standard treatment plans (Baggett et al., 2013; Fazel et al., 2014; National Academies of Sciences, Engineering, and Medicine, 2017b). For instance, someone experiencing homelessness is unable to perform clean dressing changes daily without adequate access to water. They also have higher rates of infant mortality, substance abuse, and shorter life expectancies. Additionally, they may report avoiding care because they feel discrimination from healthcare workers (Hughes et al., 2020).
In 2021, the majority of Americans relied on privately purchased insurance for their health care. Most of this insurance is made available through employers. About 35 percent of the population holds a public form of insurance in the form of Medicaid or Medicare. Medicare is for those who have been determined to need special care such as older people or those who experience certain disabilities. Medicaid is for those who need aid in receiving care, such as people who meet certain low-income guidelines (Keisler-Starkey & Bunch, 2022).
Veteran Status
Military veterans often have complex needs due to physical and psychological trauma sustained during military service and socioeconomic issues that arise after discharge (Figure 5.10). Many veterans struggle with a lack of access to healthcare benefits, sometimes based on residing in rural locations that do not have veteran-specific healthcare facilities. The Veterans Administration offers free health care to veterans who meet certain low-income guidelines, allowing these patients to be seen at any facility.
Factors Preventing Sensitivity to Diversity
Sensitivity to diversity can be hindered by several factors that are related to a person’s experiences, attitudes, and knowledge. One significant factor is a lack of exposure to diverse individuals and cultures. Limited exposure can lead to a lack of understanding and appreciation for diversity. Stereotyping and prejudice can also contribute to insensitivity, as preconceived notions or stereotypes about certain groups can lead to discrimination and bias. Personal biases can influence perceptions and attitudes toward different groups, leading to insensitivity. Additionally, a lack of education or awareness about different cultures and backgrounds can lead to misunderstandings. Overcoming these barriers requires ongoing education, open-mindedness, and a willingness to learn about and appreciate different cultures and backgrounds. It also requires actively challenging one’s biases and seeking out opportunities for exposure to diversity.
Stereotyping
The assumption that a person has the attributes, traits, beliefs, and values of a cultural group because they are a member of that group is termed stereotyping . Engaging in stereotyping prevents the ability to identify people’s needs on an individual level. One common stereotype is the assumption that all older patients are forgetful or have memory problems. This stereotype can lead to medical professionals overlooking or dismissing legitimate concerns or symptoms of older patients, attributing them solely to age-related memory decline, which can in turn lead to misdiagnosis or delayed treatment. Stereotypes can be harmful to patients and must be avoided. Culturally competent care extends beyond general knowledge of a cultural group to knowledge of the individual themself.
Cultural Imposition
The imposition of one’s own values, beliefs, and practices upon another person or group is cultural imposition . Cultural imposition runs counter to cultural humility and can manifest in various ways. Examples include disregarding a patient’s cultural practices, beliefs, and values when making medical decisions, or imposing Western medical practices on non-Western cultures without consideration for their unique cultural beliefs and practices. For instance, healthcare providers may fail to consider a patient’s traditional healing practices or the role of family members in healthcare decisions, which can lead to a breakdown in communication and a lack of trust between patients and healthcare providers. Cultural awareness can help the nurse recognize their own biases and avoid cultural imposition.
Cultural Blindness
The belief that all cultural groups are the same and share identical experiences is cultural blindness (Bhattacharya et al., 2019). Different cultural groups can have vastly different experiences within the healthcare system. Cultural blindness might lead a nurse to conclude that all treatment services are adequate for all patients, contributing to the continuation of policies that prevent diversity and inclusion . For instance, a hospital might stock consent forms available in English and Spanish exclusively. However, despite a significant local Vietnamese population, the nurse consistently faces difficulty in locating consent forms in Vietnamese for these patients. This is a result of system-wide cultural blindness. Once the nurse identifies the issue, they can escalate it and have the issue addressed by having adequate Vietnamese-language consent forms available for the patient population.
To address cultural blindness in health care, providers should receive regular cultural competency training and actively work to understand and respect the diverse backgrounds of their patients. This includes learning about cultural beliefs and practices related to health and illness, as well as developing effective communication strategies that bridge language and cultural barriers.
Culture Conflict
A culture conflict occurs when there is tension or opposition between different cultures. Often, the dominant culture weakens the cultural practices of the minority group as a result (APA, n.d.b). Culture conflict can arise in many ways, such as when a patient’s cultural beliefs around illness and healing differ from those of the healthcare provider, or when a patient’s cultural practices conflict with medical protocols. For example, a patient who refuses to receive a blood transfusion due to religious beliefs may have conflict with the nurse who sees this treatment as medically necessary.
Culture conflict can also arise when healthcare providers make assumptions or judgments about patients based on their cultural background, leading to biases and discrimination. This can result in disparities in healthcare access and outcomes for patients from diverse backgrounds. Nurses should approach such conflicts with cultural humility to ensure they are resolved without damage to the nurse-patient relationship.
Barriers to Communication
It is necessary to overcome communication barriers to maximize the patients’ opportunities for the highest quality care. According to the Agency for Healthcare Research and Quality (2020), approximately three out of 100 people in the United States have a hearing disability, and two out of 100 have a visual disability to the extent that they are blind or have trouble seeing even with corrective vision wear. Various strategies can help improve the communication process for these patients.
For patients with hearing barriers, offer print materials, text telephones (TTYs), or videos with captioning. Sign language interpreters use American Sign Language or Signed English; there are also oral and cued-speech interpreters who use articulation and gestures. When having conversations, make sure the television or other sources of background noise are silenced and the surrounding environment is free of distracting noise.
For patients with sight barriers, make sure that the lighting is at their comfort level. Whenever possible, provide assistance in the form of audio recordings, large-print materials, and screen magnifiers. Text-to-speech or Braille output screen reading software is also available.
Linguistic Competence
According to a recent study, nine percent of the U.S. population has limited English proficiency (Agency for Healthcare Research and Quality [AHRQ], 2020). Linguistically competent care aims to help reduce these discrepancies. The AHRQ defines linguistic competence as “providing readily available, culturally appropriate oral and written language services to limited English proficiency members through such means as bilingual/bicultural staff, trained medical interpreters, and qualified translators” (AHRQ, 2019).
Educational materials, instructions, and consent forms should be offered in the patient’s preferred language and written using simple language. When caring for a patient whose primary language is not English and they have a limited ability to speak, read, write, or understand the English language, seek the services of a trained medical interpreter. Healthcare facilities are mandated by The Joint Commission to provide qualified medical interpreters. Use of a trained medical interpreter is linked to fewer communication errors, shorter hospital stays, reduced thirty-day readmission rates, and improved patient satisfaction.
Refrain from asking a family member to act as an interpreter. The patient may withhold sensitive information from them, or family members may possibly edit or change the information provided. Unfamiliarity with medical terminology can also cause misunderstanding and errors.
Medical interpreters may be on-site or available by videoconferencing or telephone. The nurse should also consider coordinating patient and family member conversations with other healthcare team members to streamline communication, while being aware of cultural implications such as who can discuss what healthcare topics and who makes the decisions. When possible, obtain a medical interpreter of the same gender as the patient to prevent potential embarrassment if a sensitive matter is being discussed.
Some additional guidelines for working with a medical interpreter are as follows:
- Allow extra time for the interview or conversation with the patient.
- Whenever possible, meet with the interpreter beforehand to provide background.
- Document the name of the medical interpreter in the progress note.
- Always face and address the patient directly, using a normal tone of voice. Do not direct questions or conversation to the interpreter.
- Speak in the first person (using “I”).
- Avoid using idioms, such as, “Are you feeling under the weather today?” Avoid abbreviations, slang, jokes, and jargon.
- Speak in short paragraphs or sentences. Ask only one question at a time. Allow sufficient time for the interpreter to finish interpreting before beginning another statement or topic.
- Ask the patient to repeat any instructions and explanations given to verify that they understood.


14.3: Where Can we go Next?
As emphasized by Harvey and Pagel (1991) , comparative methods have proven to be an essential tool in identifying and describing adaptations. However, the scope of comparative methods has broadened, and now seeks to address long-standing theories of macroevolution. It is in this area that I think comparative methods has promise, but awaits new developments and ideas to really make progress towards the future.
The main challenge, I think, is in identifying and testing broad theories of macroevolution. Too many papers focus on “classic” verbal models of macroevolution – many of which have been defined in contradictory ways over the years and can never really be tested. At the same time, new quantitative theories of macroevolution are lacking.
Let me explore this in a bit more detail using the idea of adaptive radiation and the related concept of ecological opportunity. Perhaps, the theory goes, occasionally lineages enter a new adaptive zone full of niches just waiting to be occupied; the lineage then evolves rapidly to fill those niches. Based on this definition, there are several sets of criteria that one might apply to decide whether or not a particular lineage has experienced such an adaptive radiation. There are a few alternatives that are sometimes contrasted to this pattern, like nonadaptive radiation.
The concept of adaptive radiation has been very fruitful for inspiring creative and interesting work on model clades, but (in my opinion) we have mostly failed in terms of really predicting adaptive radiations and separating the phenomenon from ‘normal’ evolution. For example, most studies identify lineages undergoing adaptive radiation a priori . Even when the goal is to identify adaptive radiations, some criteria seem hard to pin down; for example, one can require evidence of adaptation, but surely every lineage on the planet has experienced selection and adapted in at least some way over its history. Likewise, we can require common descent, but there is only one tree of life on Earth (that we know!), so eventually one will find that as well. And authors differ dramatically on whether or not adaptive radiations need to be rapid relative to trait evolution and/or lineage diversification in other lineages. Finally, although a few studies have been able to characterize the unique features of adaptive radiations compared to their close relatives, comparisons across broader sections of the tree of life have mostly failed. We still do not know for certain if there is anything that links the “classic” adaptive radiations (e.g. anoles, Darwin’s finches, mammals) and distinguishes them from evolution in normal clades.
Comparative methods have cast doubt on another cornerstone of macroevolution, that of punctuated equilibrium. As we have argued, comparative methods have had varying success in tackling each of the parts of PE theory, but we can see little evidence to link them into a cohesive whole. For one thing, there is too much evidence that lineages adapt and evolve along branches of phylogenetic trees, rather than just at speciation. Quantitative tests do tend to find some statistical support for the idea that change depends on both anagenesis and speciation, but “pure” punctuated equilibrium is increasingly hard to defend.
As for other major macroevolutionary theories, some have received mixed support (e.g. Dollo’s law, escape-and-radiation, cospeciation, key innovations), while others have hardly been tested in a comparative framework, probably due to a lack of methods (the geographic mosaic theory, holey adaptive landscapes).