7.4: Chemical Equations
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Learning Objectives
- Identify the reactants and products in any chemical reaction.
- Convert word equations into chemical equations.
- Use the common symbols, \(\left( s \right)\), \(\left( l \right)\), \(\left( g \right)\), \(\left( aq \right)\), and \(\rightarrow\) appropriately when writing a chemical reaction.
In a chemical change, new substances are formed. In order for this to occur, the chemical bonds of the substances break, and the atoms that compose them separate and rearrange themselves into new substances with new chemical bonds. When this process occurs, we call it a chemical reaction. A chemical reaction is the process in which one or more substances are changed into one or more new substances.
Reactants and Products
To describe a chemical reaction, we need to indicate what substances are present at the beginning and what substances are present at the end. The substances that are present at the beginning are called reactants and the substances present at the end are called products .
Sometimes when reactants are put into a reaction vessel, a reaction will take place to produce products. Reactants are the starting materials, that is, whatever we have as our initial ingredients. The products are just that—what is produced—or the result of what happens to the reactants when we put them together in the reaction vessel. If we think about baking chocolate chip cookies, our reactants would be flour, butter, sugar, vanilla, baking soda, salt, egg, and chocolate chips. What would be the products? Cookies! The reaction vessel would be our mixing bowl.
\[ \underbrace{\text{Flour} + \text{Butter} + \text{Sugar} + \text{Vanilla} + \text{Baking Soda} + \text{Eggs} + \text{Chocolate Chips}}_{\text{Ingredients = Reactants}} \rightarrow \underbrace{\text{Cookies}}_{\text{Product}} \nonumber \]
Writing Chemical Equations
When sulfur dioxide is added to oxygen, sulfur trioxide is produced. Sulfur dioxide and oxygen, \(\ce{SO_2} + \ce{O_2}\), are reactants and sulfur trioxide, \(\ce{SO_3}\), is the product.
\[ \underbrace{\ce{2 SO2(g) + O2(g) }}_{\text{Reactants}} \rightarrow \underbrace{\ce{2SO3(g)}}_{\text{Products}} \nonumber \]
In chemical reactions, the reactants are found before the symbol "\(\rightarrow\)" and the products are found after the symbol "\(\rightarrow\)". The general equation for a reaction is:
\[\text{Reactants } \rightarrow \text{Products} \nonumber \]
There are a few special symbols that we need to know in order to "talk" in chemical shorthand. In the table below is the summary of the major symbols used in chemical equations. Table \(\PageIndex{1}\) shows a listing of symbols used in chemical equations.
| Symbol | Description | Symbol | Description |
|---|---|---|---|
| \(+\) | used to separate multiple reactants or products | \(\left( s \right)\) | reactant or product in the solid state |
| \(\rightarrow\) | yield sign; separates reactants from products | \(\left( l \right)\) | reactant or product in the liquid state |
| \(\rightleftharpoons\) | replaces the yield sign for reversible reactions that reach equilibrium | \(\left( g \right)\) | reactant or product in the gas state |
| \(\overset{\ce{Pt}}{\rightarrow}\) | formula written above the arrow is used as a catalyst in the reaction | \(\left( aq \right)\) | reactant or product in an aqueous solution (dissolved in water) |
| \(\overset{\Delta}{\rightarrow}\) | triangle indicates that the reaction is being heated |
Chemists have a choice of methods for describing a chemical reaction.
1. They could draw a picture of the chemical reaction.
2. They could write a word equation for the chemical reaction:
"Two molecules of hydrogen gas react with one molecule of oxygen gas to produce two molecules of water vapor."
3. They could write the equation in chemical shorthand.
\[2 \ce{H_2} \left( g \right) + \ce{O_2} \left( g \right) \rightarrow 2 \ce{H_2O} \left( g \right) \nonumber \]
In the symbolic equation, chemical formulas are used instead of chemical names for reactants and products, while symbols are used to indicate the phase of each substance. It should be apparent that the chemical shorthand method is the quickest and clearest method for writing chemical equations.
We could write that an aqueous solution of calcium nitrate is added to an aqueous solution of sodium hydroxide to produce solid calcium hydroxide and an aqueous solution of sodium nitrate. Or in shorthand we could write:
\[\ce{Ca(NO_3)_2} \left( aq \right) + 2 \ce{NaOH} \left( aq \right) \rightarrow \ce{Ca(OH)_2} \left( s \right) + 2 \ce{NaNO_3} \left( aq \right) \nonumber \]
How much easier is that to read? Let's try it in reverse. Look at the following reaction in shorthand and write the word equation for the reaction:
\[\ce{Cu} \left( s \right) + \ce{AgNO_3} \left( aq \right) \rightarrow \ce{Cu(NO_3)_2} \left( aq \right) + \ce{Ag} \left( s \right) \nonumber \]
The word equation for this reaction might read something like "solid copper reacts with an aqueous solution of silver nitrate to produce a solution of copper (II) nitrate with solid silver."
To turn word equations into symbolic equations, we need to follow the given steps:
- Identify the reactants and products. This will help you know which symbols go on each side of the arrow and where the \(+\) signs go.
- Write the correct formulas for all compounds. You will need to use the rules you learned in Chapter 5 (including making all ionic compounds charge balanced).
- Write the correct formulas for all elements. Usually this is given straight off of the periodic table. However, there are seven elements that are considered diatomic, meaning that they are always found in pairs in nature. They include those elements listed in the table.
| Element Name | Hydrogen | Nitrogen | Oxygen | Fluorine | Chlorine | Bromine | Iodine |
|---|---|---|---|---|---|---|---|
| Formula | \(H_2\) | \(N_2\) | \(O_2\) | \(F_2\) | \(Cl_2\) | \(Br_2\) | \(I_2\) |
Example \(\PageIndex{1}\)
Transfer the following symbolic equations into word equations or word equations into symbolic equations.
- \(\ce{HCl} \left( aq \right) + \ce{NaOH} \left( aq \right) \rightarrow \ce{NaCl} \left( aq \right) + \ce{H_2O} \left( l \right)\)
- Gaseous propane, \(\ce{C_3H_8}\), burns in oxygen gas to produce gaseous carbon dioxide and liquid water.
- Hydrogen fluoride gas reacts with an aqueous solution of potassium carbonate to produce an aqueous solution of potassium fluoride, liquid water, and gaseous carbon dioxide.
Solution
a. An aqueous solution of hydrochloric acid reacts with an aqueous solution of sodium hydroxide to produce an aqueous solution of sodium chloride and liquid water.
b. Reactants: propane (\(\ce{C_3H_8}\)) and oxygen (\(\ce{O_2}\))
Product: carbon dioxide (\(\ce{CO_2}\)) and water (\(\ce{H_2O}\))
\[\ce{C_3H_8} \left( g \right) + \ce{O_2} \left( g \right) \rightarrow \ce{CO_2} \left( g \right) + \ce{H_2O} \left( l \right) \nonumber \]
c. Reactants: hydrogen fluoride and potassium carbonate
Products: potassium fluoride, water, and carbon dioxide
\[\ce{HF} \left( g \right) + \ce{K_2CO_3} \left( aq \right) \rightarrow \ce{KF} \left( aq \right) + \ce{H_2O} \left( l \right) + \ce{CO_2} \left( g \right) \nonumber \]
Exercise \(\PageIndex{1}\)
Transfer the following symbolic equations into word equations or word equations into symbolic equations.
- Hydrogen gas reacts with nitrogen gas to produce gaseous ammonia.
- \(\ce{HCl} \left( aq \right) + \ce{LiOH} \left( aq \right) \rightarrow \ce{LiCl} \left( aq \right) + \ce{H_2O} \left( l \right)\)
- Copper metal is heated with oxygen gas to produce solid copper(II) oxide.
- Answer a
- \(H_2 (g) + N_2 (g) \rightarrow NH_3 (g)\)
- Answer b
- An aqueous solution of hydrochloric acid reacts with an aqueous solution of lithium hydroxide to produce an aqueous solution of lithium chloride and liquid water.
- Answer c
- \(Cu (s) + O_2 (g) \rightarrow CuO (s)\)
Summary
- A chemical reaction is the process by which one or more substances are changed into one or more new substances.
- Chemical reactions are represented by chemical equations.
- Chemical equations have reactants on the left, an arrow that is read as "yields", and the products on the right.


10: Liquids and Solids
The great distances between atoms and molecules in a gaseous phase, and the corresponding absence of any significant interactions between them, allows for simple descriptions of many physical properties that are the same for all gases, regardless of their chemical identities. As described in the final module of the chapter on gases, this situation changes at high pressures and low temperatures—conditions that permit the atoms and molecules to interact to a much greater extent. In the liquid and solid states, these interactions are of considerable strength and play an important role in determining a number of physical properties that do depend on the chemical identity of the substance. In this chapter, the nature of these interactions and their effects on various physical properties of liquid and solid phases will be examined.
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- 10.1: Prelude to Liquids and Solids
- In the liquid and solid states, these interactions are of considerable strength and play an important role in determining a number of physical properties that do depend on the chemical identity of the substance. In this chapter, the nature of these interactions and their effects on various physical properties of liquid and solid phases will be examined.
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- 10.2: Intermolecular Forces
- The physical properties of condensed matter (liquids and solids) can be explained in terms of the kinetic molecular theory. In a liquid, intermolecular attractive forces hold the molecules in contact, although they still have sufficient kinetic energy to move past each other. Intermolecular attractive forces, collectively referred to as van der Waals forces, are responsible for the behavior of liquids and solids and are electrostatic in nature.
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- 10.3: Properties of Liquids
- The intermolecular forces between molecules in the liquid state vary depending upon their chemical identities and result in corresponding variations in various physical properties. Cohesive forces between like molecules are responsible for a liquid’s viscosity (resistance to flow) and surface tension. Adhesive forces between the molecules of a liquid and different molecules composing a surface in contact with the liquid are responsible for surface wetting and capillary rise.
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- 10.4: Phase Transitions
- Phase transitions are processes that convert matter from one physical state into another. There are six phase transitions between the three phases of matter. Melting, vaporization, and sublimation are all endothermic processes, requiring an input of heat to overcome intermolecular attractions. The reciprocal transitions of freezing, condensation, and deposition are all exothermic processes, involving heat as intermolecular attractive forces are established or strengthened.
Contributors and Attributions
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Paul Flowers (University of North Carolina - Pembroke), Klaus Theopold (University of Delaware) and Richard Langley (Stephen F. Austin State University) with contributing authors. Textbook content produced by OpenStax College is licensed under a Creative Commons Attribution License 4.0 license. Download for free at<EMAIL_ADDRESS>).


15: Endocrine System
In order to survive, animals must constantly adapt to changes in the environment. The nervous and endocrine systems both work together to bring about this adaptation. In general the nervous system responds rapidly to short-term changes by sending electrical impulses along nerves and the endocrine system brings about longer-term adaptations by sending out chemical messengers called hormones into the bloodstream. (Thumbnail image credit: "The Endocrine System" by OpenStax College is licensed under CC BY 3.0 )
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- 15.2: An Overview of the Endocrine System
- Communication is a process in which a sender transmits signals to one or more receivers to control and coordinate actions. In the human body, two major organ systems participate in relatively “long distance” communication: the nervous system and the endocrine system. Together, these two systems are primarily responsible for maintaining homeostasis in the body.
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- 15.3: Pituitary Gland and Hypothalamus
- The hypothalamus–pituitary complex can be thought of as the “command center” of the endocrine system. This complex secretes several hormones that directly produce responses in target tissues, as well as hormones that regulate the synthesis and secretion of hormones of other glands. In addition, the hypothalamus–pituitary complex coordinates the messages of the endocrine and nervous systems.
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- 15.4: Thyroid Gland
- A butterfly-shaped organ, the thyroid gland is located anterior to the trachea, just inferior to the larynx. The medial region, called the isthmus, is flanked by wing-shaped left and right lobes. Each of the thyroid lobes are embedded with parathyroid glands, primarily on their posterior surfaces. The tissue of the thyroid gland is composed mostly of thyroid follicles. The follicles are made up of a central cavity filled with a sticky fluid called colloid.
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- 15.5: Parathyroid Glands
- The parathyroid glands are tiny, round structures usually found embedded in the posterior surface of the thyroid gland. Most people have four parathyroid glands. The primary functional cells of the parathyroid glands are the chief cells that release parathyroid hormone to help maintain calcium homeostasis.
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- 15.6: Adrenal Glands
- The adrenal glands, located on the superior surface of the kidneys, release the hormones aldosterone, which regulates blood sodium concentrations, glucocorticoid hormones such as cortisol that regulate blood glucose levels and long-term stress responses, and epinephrine and norepinephrine that stimulate the fight-or-flight stress response.
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- 15.7: Pineal Gland
- Recall that the hypothalamus, part of the diencephalon of the brain, sits inferior and somewhat anterior to the thalamus. Inferior but somewhat posterior to the thalamus is the pineal gland, a tiny endocrine gland whose functions are not entirely clear. The pinealocyte cells that make up the pineal gland are known to produce and secrete the amine hormone melatonin, which is derived from serotonin.
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- 15.8: Gonadal and Placental Hormones
- This section briefly discusses the hormonal role of the gonads—the testes and ovaries—which produce the sex cells (sperm and ova, respectively) and secrete the gonadal hormones. The roles of the gonadotropins released from the anterior pituitary (FSH and LH) were discussed earlier.
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- 15.9: Endocrine Pancreas
- The pancreas is a long, slender organ, most of which is located posterior to the bottom half of the stomach. Although it is primarily an exocrine gland, secreting a variety of digestive enzymes, the pancreas has an endocrine function. Its pancreatic islets—clusters of cells formerly known as the islets of Langerhans—secrete the hormones glucagon, insulin, somatostatin, and pancreatic polypeptide.
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- 15.10: Organs with Secondary Endocrine Functions
- In your study of anatomy, you have already encountered a few of the many organs of the body that have secondary endocrine functions. Here, you will learn about the hormone-producing activities of the heart, gastrointestinal tract, kidneys, skeleton, adipose tissue, skin, and thymus.
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- 15.11: Development and Aging of the Endocrine System
- The endocrine system originates from all three germ layers of the embryo, including the endoderm, ectoderm, and mesoderm. In general, different hormone classes arise from distinct germ layers. Aging affects the endocrine glands, potentially affecting hormone production and secretion, and can cause disease. The production of hormones, such as human growth hormone, cortisol, aldosterone, sex hormones, and the thyroid hormones, decreases with age.


19.2A: Lymphatic Vessel Structure
The lymphatic structure is based on that of blood vessels.
- Describe lymphatic circulation and the structure of lymphatic vessels
Key Points
- Lymph (or lymphatic ) vessels are thin-walled valved structures that carry lymph.
- Lymph vessels are lined by endothelial cells and have a thin layer of smooth muscles and adventitia that bind the lymph vessels to the surrounding tissue.
- Lymph movement occurs despite low pressure due to smooth muscle action, valves, and compression during contraction of adjacent skeletal muscle and arterial pulsation.
- When the pressure inside a lymphangion becomes high enough, lymph fluid will push through the semilunar valve into the next lymphangion, while the valve then closes.
- Lymph vessels are structurally very similar to blood vessels.
- Valves prevent backwards flow of lymph fluid, which allows the lymphatic system to function without a central pump.
Key Terms
- lymphagion : The space between two semilunar valves of the lymphatic vessels that forms a distinct functional unit for the forward flow of lymph.
- adventitia : The outermost layer of connective tissue encasing a visceral organ or vessel.
- ISF : Interstitial (or tissue) fluid, a solution that bathes and surrounds the cells of multicellular animals. It is the main component of extracellular fluid, which also includes plasma and transcellular fluid.
- endothelial cells : A thin layer of cells that lines the interior surface of blood and lymphatic vessels, forming an interface between circulating blood or lymph in the lumen and the rest of the vessel wall.
The general structure of lymphatic vessels is similar to that of blood vessels since these are the only two types of vessels in the body. While blood and lymph fluid are two separate substances, both are composed of the same water (plasma or fluid) found elsewhere in the body.
Layers of Lymph Vessels
The endothelium, a general term for the inner layer of a vessel, is composed of an inner lining of single, flattened epithelial cells (simple squamous epithelium). This layer mechanically transports fluid. It sits on a highly permeable basement membrane made out of extracellular matrix that separates the endothelium from the other layers. The endothelium is designed with junctions between cells that allow interstitial fluid to flow into the lumen when pressure becomes high enough (such as from blood capillary hydrostatic pressure), but does not normally allow lymph fluid to leak back out into the interstitial space.
The next layer is smooth muscles arranged in a circular fashion around the endothelium that alters the pressure inside the lumen (space) inside the vessel by contracting and relaxing. The activity of smooth muscles allows lymph vessels to slowly pump lymph fluid through the body without a central pump or heart. By contrast, the smooth muscles in blood vessels are involved in vasoconstriction and vasodilation instead of fluid pumping.
The outermost layer is the adventitia, consisting of fibrous tissue. It is made primarily out of collagen and serves to anchor the lymph vessels to structures within the body for stability. Larger lymph vessels have many more layers of adventitia than do smaller lymph vessels. The smallest vessels, such as the lymphatic capillaries, may have no outer adventitia. As they proceed forward and integrate into the larger lymph vessels, they develop adventitia and smooth muscle. Blood vessels also have adventitia, sometimes referred to as tunica.
Lymphatic Valves
One of the main structural features of lymph vessels is their valves, which are semilunar structures attached to opposite sides of the lymphatic endothelium. Valves are found in larger lymph vessels and collecting vessels and are absent in the lymphatic capillaries. The valves is to prevent backflow of fluid, so that lymph eventually flows forward instead of falling backwards. When the pressure of lymph fluid increase to a certain point due to filling with more lymph fluid or from smooth muscle contraction, the fluid will be pushed through the valve (opening it) into the next chamber of the vessel (called a lymphangion). As the pressure falls, the open valve then closes so that the lymph fluid cannot flow backwards.
Lymph Vessel : Diagram representing propulsion of lymph through a lymph vessel.
A lymphangion is the term for the space between two semilunar valves in a lymphatic vessel, functional unit of the lymphatic system. Lymph fluid can only flow forward through lymphangions due to the closing of valves after fluid is pushed through by fluid accumulation, smooth muscle contraction, or skeletal muscle contraction.
Without valves, the lymphatic system would be unable to function without a central pump. Smooth muscle contractions only cause small changes in pressure and volume within the lumen of the lymph vessels, so the fluid would just move backwards when the pressure dropped. Blood vessels also have valves, but only in low pressure venous circulation. They function similarly to lymphatic valves, though are comparatively more dependent on skeletal muscle contractions.


30.25: Plant Defense Mechanisms - Against Pathogens
Plants defend against pathogens with barriers, secondary metabolites, and antimicrobial compounds.
- Identify plant defense responses to pathogens
Defense Responses Against Pathogens
Pathogens are agents of disease. These infectious microorganisms, such as fungi, bacteria, and nematodes, live off of the plant and damage its tissues. Plants have developed a variety of strategies to discourage or kill attackers.
The first line of defense in plants is an intact and impenetrable barrier composed of bark and a waxy cuticle. Both protect plants against pathogens.
A plant’s exterior protection can be compromised by mechanical damage, which may provide an entry point for pathogens. If the first line of defense is breached, the plant must resort to a different set of defense mechanisms, such as toxins and enzymes. Secondary metabolites are compounds that are not directly derived from photosynthesis and are not necessary for respiration or plant growth and development. Many metabolites are toxic and can even be lethal to animals that ingest them.
Additionally, plants have a variety of inducible defenses in the presence of pathogens. In addition to secondary metabolites, plants produce antimicrobial chemicals, antimicrobial proteins, and antimicrobial enzymes that are able to fight the pathogens. Plants can close stomata to prevent the pathogen from entering the plant. A hypersensitive response, in which the plant experiences rapid cell death to fight off the infection, can be initiated by the plant; or it may use endophyte assistance: the roots release chemicals that attract other beneficial bacteria to fight the infection.
Mechanical wounding and predator attacks activate defense and protective mechanisms in the damaged tissue and elicit long-distancing signaling or activation of defense and protective mechanisms at sites farther from the injury location. Some defense reactions occur within minutes, while others may take several hours.
Key Points
- Many plants have impenetrable barriers, such as bark and waxy cuticles, or adaptations, such as thorns and spines, to protect them from pathogens.
- If pathogens breach a plant’s barriers, the plant can respond with secondary metabolites, which are often toxic compounds, such as glycol cyanide, that may harm the pathogen.
- Plants produce antimicrobial chemicals, antimicrobial proteins, and antimicrobial enzymes that are able to fight the pathogens.
Contributions and Attributions
- Plant defense against herbivory. Provided by : Wikimedia. Located at : en.Wikipedia.org/wiki/Plant_d...inst_herbivory . License : Public Domain: No Known Copyright
- Plant defense against herbivory. Provided by : Wikimedia. Located at : en.Wikipedia.org/wiki/Plant_d...inst_herbivory . License : Public Domain: No Known Copyright
- Plant defense against herbivory. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/Plant_d...inst_herbivory . License : Public Domain: No Known Copyright
- Plant defense against herbivory. Provided by : Wikimedia. Located at : en.Wikipedia.org/wiki/Plant_d...inst_herbivory . License : Public Domain: No Known Copyright
- Plant defense against herbivory. Provided by : Wikimedia. Located at : en.Wikipedia.org/wiki/Plant_d...inst_herbivory . License : Public Domain: No Known Copyright
- Plant defense against herbivory. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/Plant_defense_against_herbivory . License : Public Domain: No Known Copyright


1.1: Dimensions of Wellness
What is Wellness?
Wellness is being in good physical and mental health. Because mental health and physical health are linked, problems in one area can impact the other. At the same time, improving your physical health can also benefit your mental health, and vice versa. It is important to make healthy choices for both your physical and mental well-being.
Remember that wellness is not just the absence of illness or stress. You can still strive for wellness even if you are experiencing these challenges in your life.
What are the Nine Dimensions of Wellness?
Learning about the Nine Dimensions of Wellness can help you choose how to make wellness a part of your everyday life.
The Nine Dimensions of Wellness are:
- Emotional : Coping effectively with life and expressing emotions in an appropriate manner.
- Environmental : Occupying pleasant, healthy, and safe environments that support well-being; positively impacting the quality of our surroundings (including protecting and preserving nature).
- Financial : Achieving satisfaction with current and future financial situations; handling finances wisely.
- Intellectual : Recognizing creative abilities and finding ways to expand knowledge and skills; being open-minded.
- Occupational : Personal fulfillment and enrichment from one’s work and/or responsibilities.
- Physical : Recognizing the need for physical activity, healthy foods, and adequate sleep; avoiding unhealthy habits.
- Social : Developing a sense of connection, belonging, and sustained support system; having positive relationships.
- Spiritual : Having a sense of purpose and meaning in life; establishing peace, harmony, and balance in our lives.
- *Cultural : The way you interact with others who are different than you; understanding and celebrating our differences. (*recently added).
Learn more about the Eight Dimensions of Wellness (does not include Cultural wellness) by watching the video below:
Your Own Views on Health and Wellness
Reflect on the following questions:
- What does health mean to you?
- How important is health to you?
- What are some of your healthy habits?
- Which dimensions of wellness do you need to work on the most?
Query \(\PageIndex{1}\)
Check your Learning: The 9 Dimensions of Wellness
Contributors and Attributions
Public domain content
- Eight Dimensions of Wellness. Authored by : Substance Abuse and Mental Health Services Administration . Provided by : U.S. Department of Health and Human Services. Located at : http://www.samhsa.gov/wellness-initiative/eight-dimensions-wellness . License : Public Domain: No Known Copyright
- Video - The Eight Dimensions of Wellness. Authored by : SAMHSA. Provided by : U.S. Department of Health and Human Services. Located at : https://www.youtube.com/watch?v=tDzQdRvLAfM&feature=youtu.be . License : Public Domain: No Known Copyright


9.6: Mercury
By the end of this section, you will be able to:
- Characterize the orbit of Mercury around the Sun
- Describe Mercury’s structure and composition
- Explain the relationship between Mercury’s orbit and rotation
- Describe the topography and features of Mercury’s surface
- Summarize our ideas about the origin and evolution of Mercury
Mercury’s Orbit
The planet Mercury is similar to the Moon in many ways. Like the Moon, it has no atmosphere, and its surface is heavily cratered. As described later in this chapter, it also shares with the Moon the likelihood of a violent birth.
Mercury is the nearest planet to the Sun, and, in accordance with Kepler’s third law, it has the shortest period of revolution about the Sun (88 of our days) and the highest average orbital speed (48 kilometers per second). It is appropriately named for the fleet-footed messenger god of the Romans. Because Mercury remains close to the Sun, it can be difficult to pick out in the sky. As you might expect, it’s best seen when its eccentric orbit takes it as far from the Sun as possible.
The semimajor axis of Mercury’s orbit —that is, the planet’s average distance from the Sun—is 58 million kilometers, or 0.39 AU. However, because its orbit has the high eccentricity of 0.206, Mercury’s actual distance from the Sun varies from 46 million kilometers at perihelion to 70 million kilometers at aphelion (the ideas and terms that describe orbits were introduced in Orbits and Gravity).
Composition and Structure
Mercury’s mass is one-eighteenth that of Earth, making it the smallest terrestrial planet. Mercury is the smallest planet (except for the dwarf planets), having a diameter of 4878 kilometers, less than half that of Earth. Mercury’s density is 5.4 g/cm 3 , much greater than the density of the Moon, indicating that the composition of those two objects differs substantially.
Mercury’s composition is one of the most interesting things about it and makes it unique among the planets. Mercury’s high density tells us that it must be composed largely of heavier materials such as metals. The most likely models for Mercury’s interior suggest a metallic iron-nickel core amounting to 60% of the total mass, with the rest of the planet made up primarily of silicates. The core has a diameter of 3500 kilometers and extends out to within 700 kilometers of the surface. We could think of Mercury as a metal ball the size of the Moon surrounded by a rocky crust 700 kilometers thick (Figure 9.20). Unlike the Moon, Mercury does have a weak magnetic field. The existence of this field is consistent with the presence of a large metal core, and it suggests that at least part of the core must be liquid in order to generate the observed magnetic field. 3
The average density of a body equals its mass divided by its volume. For a sphere, density is:
Astronomers can measure both mass and radius accurately when a spacecraft flies by a body.
Using the information in this chapter, we can calculate the approximate average density of the Moon.
Solution
For a sphere,
Table 9.1 gives a value of , which is .
Using the information in this chapter, calculate the average density of Mercury. Show your work. Does your calculation agree with the figure we give in this chapter?
- Answer
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That matches the value given in Table 9.1 when g/cm 3 is converted into kg/m 3 .
Mercury’s Strange Rotation
Visual studies of Mercury ’s indistinct surface markings were once thought to indicate that the planet kept one face to the Sun (as the Moon does to Earth). Thus, for many years, it was widely believed that Mercury’s rotation period was equal to its revolution period of 88 days, making one side perpetually hot while the other was always cold.
Radar observations of Mercury in the mid-1960s, however, showed conclusively that Mercury does not keep one side fixed toward the Sun. If a planet is turning, one side seems to be approaching Earth while the other is moving away from it. The resulting Doppler shift spreads or broadens the precise transmitted radar-wave frequency into a range of frequencies in the reflected signal (Figure 9.21). The degree of broadening provides an exact measurement of the rotation rate of the planet.
Mercury’s period of rotation (how long it takes to turn with respect to the distant stars) is 59 days, which is just two-thirds of the planet’s period of revolution. Subsequently, astronomers found that a situation where the spin and the orbit of a planet (its year) are in a 2:3 ratio turns out to be stable. (See What a Difference a Day Makes for more on the effects of having such a long day on Mercury.)
Mercury, being close to the Sun, is very hot on its daylight side; but because it has no appreciable atmosphere, it gets surprisingly cold during the long nights. The temperature on the surface climbs to 700 K (430 °C) at noontime. After sunset, however, the temperature drops, reaching 100 K (–170 °C) just before dawn. (It is even colder in craters near the poles that receive no sunlight at all.) The range in temperature on Mercury is thus 600 K (or 600 °C), a greater difference than on any other planet.
Mercury rotates three times for each two orbits around the Sun. It is the only planet that exhibits this relationship between its spin and its orbit, and there are some interesting consequences for any observers who might someday be stationed on the surface of Mercury.
Here on Earth, we take for granted that days are much shorter than years. Therefore, the two astronomical ways of defining the local “day”—how long the planet takes to rotate and how long the Sun takes to return to the same position in the sky—are the same on Earth for most practical purposes. But this is not the case on Mercury. While Mercury rotates (spins once) in 59 Earth days, the time for the Sun to return to the same place in Mercury’s sky turns out to be two Mercury years, or 176 Earth days. (Note that this result is not intuitively obvious, so don’t be upset if you didn’t come up with it.) Thus, if one day at noon a Mercury explorer suggests to her companion that they should meet at noon the next day, this could mean a very long time apart!
To make things even more interesting, recall that Mercury has an eccentric orbit, meaning that its distance from the Sun varies significantly during each mercurian year. By Kepler’s law, the planet moves fastest in its orbit when closest to the Sun. Let’s examine how this affects the way we would see the Sun in the sky during one 176-Earth-day cycle. We’ll look at the situation as if we were standing on the surface of Mercury in the center of a giant basin that astronomers call Caloris (Figure 9.23).
At the location of Caloris, Mercury is most distant from the Sun at sunrise; this means the rising Sun looks smaller in the sky (although still more than twice the size it appears from Earth). As the Sun rises higher and higher, it looks bigger and bigger; Mercury is now getting closer to the Sun in its eccentric orbit. At the same time, the apparent motion of the Sun slows down as Mercury’s faster motion in orbit begins to catch up with its rotation.
At noon, the Sun is now three times larger than it looks from Earth and hangs almost motionless in the sky. As the afternoon wears on, the Sun appears smaller and smaller, and moves faster and faster in the sky. At sunset, a full Mercury year (or 88 Earth days after sunrise), the Sun is back to its smallest apparent size as it dips out of sight. Then it takes another Mercury year before the Sun rises again. (By the way, sunrises and sunsets are much more sudden on Mercury, since there is no atmosphere to bend or scatter the rays of sunlight.)
Astronomers call locations like the Caloris Basin the “hot longitudes” on Mercury because the Sun is closest to the planet at noon, just when it is lingering overhead for many Earth days. This makes these areas the hottest places on Mercury.
We bring all this up not because the exact details of this scenario are so important but to illustrate how many of the things we take for granted on Earth are not the same on other worlds. As we’ve mentioned before, one of the best things about taking an astronomy class should be ridding you forever of any “Earth chauvinism” you might have. The way things are on our planet is just one of the many ways nature can arrange reality.
The Day on Mercury visualization shows how Mercury’s slow rotation leads to very long days and how this combines with its highly elliptical orbit to cause some unusual motions of the sun in the sky. Note the stick figure on the surface of Mercury; the Day/Night box shows what that stick figure would see in the sky.
The Surface of Mercury
The first close-up look at Mercury came in 1974, when the US spacecraft Mariner 10 passed 9500 kilometers from the surface of the planet and transmitted more than 2000 photographs to Earth, revealing details with a resolution down to 150 meters. Subsequently, the planet was mapped in great detail by the MESSENGER spacecraft, which was launched in 2004 and made multiple flybys of Earth, Venus, and Mercury before settling into orbit around Mercury in 2011. It ended its life in 2015, when it was commanded to crash into the surface of the planet.
Mercury’s surface strongly resembles the Moon in appearance (Figure 9.22 and Figure 9.23). It is covered with thousands of craters and larger basins up to 1300 kilometers in diameter. Some of the brighter craters are rayed, like Tycho and Copernicus on the Moon, and many have central peaks. There are also scarps (cliffs) more than a kilometer high and hundreds of kilometers long, as well as ridges and plains.
MESSENGER instruments measured the surface composition and mapped past volcanic activity. One of its most important discoveries was the verification of water ice (first detected by radar) in craters near the poles, similar to the situation on the Moon, and the unexpected discovery of organic (carbon-rich) compounds mixed with the water ice.
Scientists working with data from the MESSENGER mission put together a rotating globe of Mercury, in false color, showing some of the variations in the composition of the planet’s surface. You can watch it spin.
Most of the mercurian features have been named in honor of artists, writers, composers, and other contributors to the arts and humanities, in contrast with the scientists commemorated on the Moon. Among the named craters are Bach, Shakespeare, Tolstoy, Van Gogh, and Scott Joplin.
There is no evidence of plate tectonics on Mercury. However, the planet’s distinctive long scarps can sometimes be seen cutting across craters; this means the scarps must have formed later than the craters (Figure 9.24). These long, curved cliffs appear to have their origin in the slight compression of Mercury’s crust. Apparently, at some point in its history, the planet shrank, wrinkling the crust, and it must have done so after most of the craters on its surface had already formed.
If the standard cratering chronology applies to Mercury, this shrinkage must have taken place during the last 4 billion years and not during the solar system’s early period of heavy bombardment.
The Origin of Mercury
The problem with understanding how Mercury formed is the reverse of the problem posed by the composition of the Moon. We have seen that, unlike the Moon, Mercury is composed mostly of metal. However, astronomers think that Mercury should have formed with roughly the same ratio of metal to silicate as that found on Earth or Venus. How did it lose so much of its rocky material?
The most probable explanation for Mercury’s silicate loss may be similar to the explanation for the Moon’s lack of a metal core. Mercury is likely to have experienced several giant impacts very early in its youth, and one or more of these may have torn away a fraction of its mantle and crust, leaving a body dominated by its iron core. A recent alternative explanation suggests that, early on, heat from the young Sun evaporated much of the lighter, more volatile, silicates in the material that formed Mercury, leaving the planet with a majority of metals.
You can follow some of NASA’s latest research on Mercury and see some helpful animations on the MESSENGER web page.
Today, astronomers recognize that the early solar system was a chaotic place, with the final stages of planet formation characterized by impacts of great violence. Some objects of planetary mass have been destroyed, whereas others could have fragmented and then re-formed, perhaps more than once. Both the Moon and Mercury, with their strange compositions, bear testimony to the catastrophes that must have characterized the solar system during its youth.
Footnotes
- 3 Recall from the Radiation and Spectra chapter that magnetism is an effect of moving electric charges. In atoms of metals, the outer electrons are easier to dislodge and they can form a current when the metal is in liquid form and can flow.


13.8: Summary
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- Jennifer Hasty, David G. Lewis, & Marjorie M. Snipes
- OpenStax
Religion is found across all cultures, and yet it can be difficult to define. French sociologist Émile Durkheim used an empirical definition, identifying religion as an institution related to “sacred things,” with beliefs, practices, and a social organization. This definition provides a checklist for studying religion. Anthropologist Clifford Geertz, on the other hand, defines it as a system of symbols connected to moods, motivations, and a “general order of existence.” While more abstract, this definition addresses the meaning and sense of identity that religion conveys to practitioners. In the United States today, people identify themselves religiously in a number of ways, including as “nones,” people with no religious affiliation. Nones, agnostics, and atheists do have worldviews particular to their cultures, and they sometimes also have spiritual beliefs.
Religion has several common characteristics. Witchcraft and sorcery became part of religion as it evolved to adapt to world populations. In these cases, religion expresses social conflict within the society. Magic is also part of every religion, as religious belief systems are based on cause and effect, and anthropologists see magic as a profound human act of faith. Most religions also involve supernatural forces, such as gods and goddesses. Monotheistic religions focus on a single named god, while polytheistic religions involve a group of deities. Most religions have some type of leadership, either priests or shamans.
Shamanism is an early form of religion, found throughout human history, and possibly the explanation for mortuary artifacts and even cave painting. While shamanism is a healing practice, it is also a set of beliefs and practices regarding a supernatural world. As populations became larger, some shamanic cults developed into more organized and institutional forms of religion, leading to large state religions such as Christianity, Islam, and Buddhism. Shamanic practices can still be found within these larger religions.
Symbolism is common to all religions, regardless of whether they are small indigenous cults or state religious systems. Geographical space marked by symbolism can become a sacred place with specific meaning to religious practitioners. Religious myths, the stories behind the beliefs, are heavily marked with symbolic meaning. Religions can convey their beliefs through both oral and written traditions, with certain groups focused specifically on one or the other. Religious practice is known as ritual, and there are a variety of types of ritual, including rites of intensification, rites of passage, and rites of affliction.
Historically, there has been a great diversity in religious groups, including utopian religious communities that live separate from secular society and focus almost entirely on living a religious life. The Shakers are an example of this type of religious society. There are also examples of secular religion, in which the state or society itself is elevated as if it had a divine status.


2.1: Information Systems
Defining Information Systems
Almost all programs in business require students to take a course in something called information systems . But what exactly does that term mean? Let’s take a look at some of the more popular definitions, first from Wikipedia and then from a couple of textbooks:
-
“Information systems (IS) is the study of complementary networks of hardware and software that people and organizations use to collect, filter, process, create, and distribute data.”
[1]
In some organizations, a matrix reporting structure was developed in which IT personnel were placed within a department and reported to both the department management and the functional management within IS. The advantages of dedicated IS personnel for each department must be weighed against the need for more control over the strategic information resources of the company.
- “Information systems are combinations of hardware, software, and telecommunications networks that people build and use to collect, create, and distribute useful data, typically in organizational settings.” [2]
- “Information systems are interrelated components working together to collect, process, store, and disseminate information to support decision making, coordination, control, analysis, and visualization in an organization.” [3]
As you can see, these definitions focus on two different ways of describing information systems: the components that make up an information system and the role that those components play in an organization. Let’s take a look at each of these.
The Role of Information Systems
In this section, we will explore the role information systems play in an organization. Later in the text, you will learn how components collect, store, organize and distribute data throughout the organization. In fact, we might say that one of the roles of information systems is to take data and turn it into information, and then transform that into organizational knowledge. As technology has developed, this role has evolved into the backbone of the organization. To get a full appreciation of the role information systems to play, we will review how they have changed over the years.
The Mainframe Era
From the late 1950s through the 1960s, computers were seen as a way to more efficiently do calculations. These first business computers were room-sized monsters, with several refrigerator-sized machines linked together. The primary work of these devices was to organize and store large volumes of information that were tedious to manage by hand. Only large businesses, universities, and government agencies could afford them, and they took a crew of specialized personnel and specialized facilities to maintain. These devices served dozens to hundreds of users at a time through a process called time-sharing. Typical functions included scientific calculations and accounting, under the broader umbrella of “data processing.”
Registered trademark of International Business Machines
In the late 1960s, the Manufacturing Resources Planning (MRP) systems were introduced. This software, running on a mainframe computer, gave companies the ability to manage the manufacturing process, making it more efficient. From tracking inventory to creating bills of materials to scheduling production, the MRP systems (and later the MRP II systems) gave more businesses a reason to want to integrate computing into their processes. IBM became the dominant mainframe company. Nicknamed “Big Blue,” the company became synonymous with business computing. Continued improvement in software and the availability of cheaper hardware eventually brought mainframe computers (and their little sibling, the minicomputer) into most large businesses.
The PC Revolution
In 1975, the first microcomputer was announced on the cover of Popular Mechanics : the Altair 8800. Microcomputers' immediate popularity sparked the imagination of entrepreneurs everywhere, and there were quickly dozens of companies making these “personal computers.” Though at first just a niche product for computer hobbyists, improvements in usability and the availability of practical software led to growing sales. The most prominent of these early personal computer makers was a little company known as Apple Computer, headed by Steve Jobs and Steve Wozniak, with the hugely successful “Apple II.” Not wanting to be left out of the revolution, in 1981 IBM (teaming with a little company called Microsoft for their operating-system software) hurriedly released their own version of the personal computer, simply called the “PC.”  The IBM PC was named Time magazine’s “Man of the Year” for 1982.
Because of the IBM PC’s open architecture, it was easy for other companies to copy, or “clone” it. During the 1980s, many new computer companies sprung up, offering less expensive versions of the PC. This drove prices down and spurred innovation. Microsoft developed its Windows operating system and made the PC even easier to use. Common uses for the PC during this period included word processing, spreadsheets, and databases. These early PCs were not connected to any sort of network; for the most part, they stood alone as islands of innovation within the larger organization.
Client-Server
In the mid-1980s, businesses began to see the need to connect their computers together as a way to collaborate and share resources. This networking architecture was referred to as “client-server” because users would log in to the local area network (LAN) from their PC (the “client”) by connecting to a powerful computer called a “server,” which would then grant them rights to different resources on the network (such as shared file areas and a printer). Software companies began developing applications that allowed multiple users to access the same data at the same time. This evolved into software applications for communicating, with the first real popular use of electronic mail appearing at this time.
This networking and data sharing all stayed within the confines of each business, for the most part. While there was sharing of electronic data between companies, this was a very specialized function. Computers were now seen as tools to collaborate internally, within an organization. In fact, these networks of computers were becoming so powerful that they were replacing many of the functions previously performed by the larger mainframe computers at a fraction of the cost. It was during this era that the first Enterprise Resource Planning (ERP) systems were developed and run on the client-server architecture. An ERP system is a software application with a centralized database that can be used to run a company’s entire business. With separate modules for accounting, finance, inventory, human resources, and many, many more, ERP systems, with Germany’s SAP leading the way, represented the state of the art in information systems integration.
The World Wide Web an d E-Commerce
First invented in 1969, the Internet was confined to use by universities, government agencies, and researchers for many years. Its rather arcane commands and user applications made it unsuitable for mainstream use in business. One exception to this was the ability to expand electronic mail outside the confines of a single organization. While the first e-mail messages on the Internet were sent in the early 1970s, companies who wanted to expand their LAN-based e-mail started hooking up to the Internet in the 1980s. Companies began connecting their internal networks to the Internet in order to allow communication between their employees and employees at other companies. It was with these early Internet connections that the computer truly began to evolve from a computational device to a communications device.
In 1989, Tim Berners-Lee developed a simpler way for researchers to share information over the network at CERN laboratories, a concept he called the World Wide Web. [4] This invention became the launching point of the growth of the Internet as a way for businesses to share information about themselves. As web browsers and Internet connections became the norm, companies rushed to grab domain names and create websites.
In 1991, the National Science Foundation, which governed how the Internet was used, lifted restrictions on its commercial use. The year 1994 saw the establishment of both eBay and Amazon.com, two true pioneers in the use of the new digital marketplace. A mad rush of investment in Internet-based businesses led to the dot-com boom through the late 1990s, and then the dot-com bust in 2000. While much can be learned from the speculation and crazy economic theories espoused during that bubble, one important outcome for businesses was that thousands of miles of Internet connections were laid around the world during that time. The world became truly “wired” heading into the new millennium, ushering in the era of globalization.
As it became more expected for companies to be connected to the Internet, the digital world also became a more dangerous place. Computer viruses and worms, once slowly propagated through the sharing of computer disks, could now grow with tremendous speed via the Internet. Software written for a disconnected world found it very difficult to defend against these sorts of threats. A whole new industry of computer and Internet security arose.
Web 2.0
As the world recovered from the dot-com bust, the use of technology in business continued to evolve at a frantic pace. Websites became interactive; instead of just visiting a site to find out about a business and purchase its products, customers wanted to be able to customize their experience and interact with the business. This new type of interactive website, where you did not have to know how to create a web page or do any programming in order to put information online, became known as web 2.0. Web 2.0 is exemplified by blogging, social networking, and interactive comments being available on many websites.  Some industries, such as bookstores, found themselves relegated to niche status. Others, such as video rental chains and travel agencies, simply began going out of business as they were replaced by online technologies. This process of technology replacing a middleman in a transaction is called disintermediation.
As the world became more connected, new questions arose. Should access to the Internet be considered a right? Can I copy a song that I downloaded from the Internet? How can I keep information that I have put on a website private? What information is acceptable to collect from children? Technology moved so fast that policymakers did not have enough time to enact appropriate laws, making for a Wild West–type atmosphere.
The Post-PC World
After thirty years as the primary computing device used in most businesses, sales of the PC are now beginning to decline as sales of tablets and smartphones are taking off. Just as the mainframe before it, the PC will continue to play a key role in business, but will no longer be the primary way that people interact and do business. The limited storage and processing power of these devices is being offset by a move to “cloud” computing, which allows for storage, sharing, and backup of the information on a massive scale. This will require new rounds of thinking and innovation on the part of businesses as technology continues to advance.
| Era | Hardware | Operating System | Applications |
|---|---|---|---|
|
Mainframe
(1960s) |
Terminals connected to mainframe computer. |
Time-sharing
(TSO) on MVS |
Custom-written
MRP software |
|
PC
(mid-1980s) |
IBM PC or compatible. Sometimes connected to mainframe computer via
expansion card. |
MS-DOS |
WordPerfect,
Lotus 1-2-3 |
|
Client-Server
(late 80s to early 90s) |
IBM PC “clone” on a Novell Network. | Windows for Workgroups |
Microsoft
Word, Microsoft Excel |
|
World
Wide Web (mid-90s to early 2000s) |
IBM PC “clone” connected to company intranet. | Windows XP |
Microsoft
Office, Internet Explorer |
| Web 2.0 (mid-2000s to present) | Laptop connected to company Wi-Fi. | Windows 7 |
Microsoft
Office, Firefox |
|
Post-PC
(today and beyond) |
Apple iPad | iOS |
Mobile-friendly
websites, mobile apps |
Information Systems Users – Types of Users
Besides the people who work to create, administer, and manage information systems, there is one more extremely important group of people, namely, the users of information systems. This group represents a very large percentage of an organization’s employees. If the user is not able to successfully learn and use an information system, the system is doomed to failure.
Technology adoption user types
One tool that can be used to understand how users will adopt a new technology comes from a 1962 study by Everett Rogers. In his book, Diffusion of Innovation , [1] Rogers studied how farmers adopted new technologies and noticed that the adoption rate started slowly and then dramatically increased once adoption hit a certain point. He identified five specific types of technology adopters:
- Innovators . Innovators are the first individuals to adopt new technology. Innovators are willing to take risks, are the youngest in age, have the highest social class, have great financial liquidity, are very social, and have the closest contact with scientific sources and interaction with other innovators. Risk tolerance is high so there is a willingness to adopt technologies that may ultimately fail. Financial resources help absorb these failures (Rogers, 1962, p. 282).
- Early adopters . The early adopters are those who adopt innovation soon after a technology has been introduced and proven. These individuals have the highest degree of opinion leadership among the other adopter categories, which means that these adopters can influence the opinions of the largest majority. Characteristics include being younger in age, having a higher social status, possessing more financial liquidity, having advanced education, and being more socially aware than later adopters. These adopters are more discrete in adoption choices than innovators, and realize the judicious choice of adoption will help them maintain a central communication position (Rogers, 1962, p. 283).
- Early majority . Individuals in this category adopt an innovation after a varying degree of time. This time of adoption is significantly longer than the innovators and early adopters. This group tends to be slower in the adoption process, has above average social status, has contact with early adopters, and seldom holds positions of opinion leadership in a system (Rogers, 1962, p. 283).
- Late majority . The late majority will adopt an innovation after the average member of the society. These individuals approach an innovation with a high degree of skepticism, have below average social status, very little financial liquidity, are in contact with others in the late majority and the early majority, and show very little opinion leadership.
- Laggards . Individuals in this category are the last to adopt an innovation. Unlike those in the previous categories, individuals in this category show no opinion leadership. These individuals typically have an aversion to change agents and tend to be advanced in age. Laggards typically tend to be focused on “traditions,” are likely to have the lowest social status and the lowest financial liquidity, be the oldest of all other adopters and be in contact with only family and close friends. [2]
These five types of users can be translated into information technology adopters as well, and provide additional insight into how to implement new information systems within the organization. For example, when rolling out a new system, IT may want to identify the innovators and early adopters within the organization and work with them first, then leverage their adoption to drive the rest of the implementation to the other users.
New Models of Organizations
The integration of information technology has influenced the structure of organizations. The increased ability to communicate and share information has led to a “flattening” of the organizational structure due to the removal of one or more layers of management.
The network-based organizational structure is another change enabled by information systems. In a network-based organizational structure, groups of employees can work somewhat independently to accomplish a project. People with the right skills are brought together for a project and then released to work on other projects when that project is over. These groups are somewhat informal and allow for all members of the group to maximize their effectiveness.


4.10: Spectroscopy of Ethers and Epoxides
After completing this section, you should be able to
- use the 1 H NMR spectrum of an unknown ether or epoxide to determine its identity.
- identify the approximate chemical shift expected for protons attached to the carbon atoms that are bonded to oxygen in an ether or an epoxide.
Infrared Spectroscopy
Ethers are difficult to identify by IR spectroscopy. Although they show an absorption due to C–O single-bond stretching in the range 1050 to 1150 cm –1 , many other kinds of absorptions occur in the same range. Figure \(\PageIndex{1}\) shows the IR spectrum of diethyl ether and identifies the C–O stretch. Phenyl alkyl ethers show two strong absorbances for C–O stretching at 1050 and 1250 cm –1 . Figure \(\PageIndex{2}\) shows the IR spectrum of anisole.
Nuclear Magnetic Resonance Spectroscopy
1 H NMR Spectroscopy
Ethers
- Hydrogens on carbon adjacent to the ether show up in the region of 3.4-4.5 ppm.
The 1 H NMR spectrum of dipropyl ether, Figure \(\PageIndex{3}\), shows three signals with the triplet at 3.37 ppm (B) assigned to the -CH 2 - beside the ether and the other two signals upfield (1.59 and 0.93 ppm). Notice the protons closer to the electron-withdrawing oxygen atom are further downfield, indicating some deshielding. Protons at (A) and (C) are each coupled to two equivalent (B) protons. So, each of these signals appears as a triplet. The (B) protons in turn are coupled to a set of two and three equivalent protons and appears as a sextet.
Dipropyl ether
Epoxides
- Peaks in epoxides are shifted to a slightly higher field than other ethers. Hydrogens on carbons in and epoxide appear in the region of 2.5 to 3.5 ppm.
Epoxides absorb at a slightly higher field than other ethers and show characteristic resonances at 2.5 to 3.5 δ in their 1 H NMR spectra, as indicated for 1,2-epoxypropane ( 2-Methyloxirane ) in Figure \(\PageIndex{4}\). The methylene protons of this epoxide are diastereotopic, and display complex splitting (Review NMR Chapter).
2-Methyloxirane
The methylene protons of this epoxide are diastereotopic and appear as two separate peak. When looking at the 3D structure of 2-methyloxirane it is clear that each methylene hydrogen is distinctly different. Also, hydrogens attached to the carbons in eposxides tend to display complex splitting patterns .
A 3D Interactive Model of 2-Methyloxirane
Thiols
- Hydrogens on carbons adjacent to the sulfur in sulfides and thiols appear in the region of 2.0 to 2.5 ppm.
- The SH hydrogen of a thiol typically appears in the region of 1.3-1.5 ppm.
As Sulfur is not as electronegative as Oxygen, the SH proton is actively involved in splitting in this 1 H NMR spectra. In Ethanethiol, Figure \(\PageIndex{5}\), the SH proton peak at 1.39 ppm is split into a triplet, and the methylene peak at 2.55 ppm is split into a quintet.
The 1 H NMR spectrum shown is that of a cyclic ether with the formula C 4 H 8 O. Propose a structure.
- Answer
-
1,2-Epoxybutane
13 C NMR Spectra
Ethers
Ether carbon atoms also exhibit a downfield shift in the 13 C NMR spectrum, where they usually absorb in the 50 to 80 δ range. For example, the carbon atoms next to oxygen in methyl propyl ether absorb at 58.5 and 74.8 δ . Similarly, the methyl carbon in anisole absorbs at 54.8 δ .
Epoxides
Carbons that are part of the epoxide appear in the 40-60 ppm region. For example, in Figure \(\PageIndex{6}\), the carbon atoms next to oxygen in 2-Methyloxirane absorb at 48.2 δ for CH, and 47.9 δ . for CH 2 .
Thiols
As Sulfur is not as electronegative as Oxygen, carbon adjacent to the sulfur in sulfides and thiols appear in the region of 20-40 ppm. For example, in Figure \(\PageIndex{7}\), the carbon atoms next to sulfur in ethanethiol absorb at 19.71 and 19.20 δ .
The 1 C NMR spectrum shown is that of a linear ether with the formula C 6 H 14 O. Propose a structure.
- Answer
-
Dipropyl ether. Source: SDBSWeb : http://sdbs.db.aist.go.jp
Mass Spectra
Ethers, sulfides, and epoxides all have similar fragmentation patterns in mass spectra with a few subtle variations.
Fragmentation Patterns for Ethers
- The M + is may be weak or absent, but usually stronger than the corresponding alcohol.
- They primarily undergo alpha-cleavage to produce [H 2 C=O-R] +
- They can also undergo an inductive cleavage to produce R +
- Rearrangement with loss of CHR=CHR’. This fragmentation happens after an alpha-cleavage.
alpha-cleavage
inductive cleavage
rearrangement
For Example, the primary fragmentation pattern for ethyl propyl ether (M + = 88) in mass spectrometry involves:
- Alpha-cleavage at the carbon-carbon bond adjacent to the oxygen atom , leading to the formation of prominent fragment ion m/z = 59, corresponding to the loss of an ethyl radical (m = 29). The fragment m/z = 73, corresponding to the loss of a methyl radical (m= 43), is not as prominent as the previous one because the methyl radical is not as stable as larger ones.
- Inductive cleavage, the fragment ion m/z = 29 corresponds to the ethyl cation, and the fragment m/z = 43 corresponds to the propyl cation.
- Rearrangement of fragment ion m/z = 59 leads to the formation of prominent fragment ion m/z = 31, corresponding to the loss of the alkene ethene (m = 28).
Epoxides
- The M + is typically weak or absent
- They primarily undergo alpha-cleavage to produce an alkyl radical
Sulfides
- The M + is typically stronger than the corresponding ether
- They primarily undergo alpha-cleavage to produce an alkyl radical
- They can also undergo an inductive cleavage to produce R +


2.4: The Normal Distribution
There are many different types of distributions (shapes) of quantitative data. In section 1.5 we looked at different histograms and described the shapes of them as symmetric, skewed left, and skewed right. There is a special symmetric shaped distribution called the normal distribution. It is high in the middle and then goes down quickly and equally on both ends. It looks like a bell, so sometimes it is called a bell curve. One property of the normal distribution is that it is symmetric about the mean. Another property has to do with what percentage of the data falls within certain standard deviations of the mean. This property is defined as the empirical Rule.
The Empirical Rule: Given a data set that is approximately normally distributed:
Approximately 68% of the data is within one standard deviation of the mean.
Approximately 95% of the data is within two standard deviations of the mean.
Approximately 99.7% of the data is within three standard deviations of the mean.
To visualize these percentages, see the following figure.
Note: The empirical rule is only true for approximately normal distributions.
Example \(\PageIndex{1}\): Using the Empirical Rule
Suppose that your class took a test and the mean score was 75% and the standard deviation was 5%. If the test scores follow an approximately normal distribution, answer the following questions:
- What percentage of the students had scores between 65 and 85?
- What percentage of the students had scores between 65 and 75?
- What percentage of the students had scores between 70 and 80?
- What percentage of the students had scores above 85?
To solve each of these, it would be helpful to draw the normal curve that follows this situation. The mean is 75, so the center is 75. The standard deviation is 5, so for each line above the mean add 5 and for each line below the mean subtract 5. The graph looks like the following:
- From the graph we can see that 95% of the students had scores between 65 and 85.
- The scores of 65 to 75 are half of the area of the graph from 65 to 85. Because of symmetry, that means that the percentage for 65 to 85 is ½ of the 95%, which is 47.5%.
- From the graph we can see that 68% of the students had scores between 70 and 80.
- For this problem we need a bit of math. If you looked at the entire curve, you would say that 100% of all of the test scores fall under it. So because of symmetry 50% of the test scores fall in the area above the mean and 50% of the test scores fall in the area below the mean. We know from part b that the percentage from 65 to 75 is 47.5%. Because of symmetry, the percentage from 75 to 85 is also 47.5%. So the percentage above 85 is 50% - 47.5% = 2.5%.
When we look at Example \(\PageIndex{1}\), we realize that the numbers on the scale are not as important as how many standard deviations a number is from the mean. As an example, the number 80 is one standard deviation from the mean. The number 65 is 2 standard deviations from the mean. However, 80 is above the mean and 65 is below the mean. Suppose we wanted to know how many standard deviations the number 82 is from the mean. How would we do that? The other numbers were easier because they were a whole number of standard deviations from the mean. We need a way to quantify this. We will use a z-score (also known as a z-value or standardized score) to measure how many standard deviations a data value is from the mean. This is defined as:
z-score: \(z = \dfrac{x-\mu}{\sigma}\)
where \(x\) = data value (raw score)
\(z\) = standardized value (z-score or z-value)
\(\mu\) = population mean
\(\sigma\) = population standard deviation
Note: Remember that the z-score is always how many standard deviations a data value is from the mean of the distribution.
Suppose a data value has a z-score of 2.13. This tells us two things. First, it says that the data value is above the mean, since it is positive. Second, it tells us that you have to add more than two standard deviations to the mean to get to this value. Since most data (95%) is within two standard deviations, then anything outside this range would be considered a strange or unusual value. A z-score of 2.13 is outside this range so it is an unusual value. As another example, suppose a data value has a z-score of -1.34. This data value must be below the mean, since the z-score is negative, and you need to subtract more than one standard deviation from the mean to get to this value. Since this is within two standard deviations, it is an ordinary value.
An unusual value has a z-score < or a z-score > 2
A usual value has a z-score between and 2, that is \(-2 < z-score < 2\).
You may encounter standardized scores on reports for standardized tests or behavior tests as mentioned previously.
Example \(\PageIndex{2}\): Calculating Z-Scores
Suppose that your class took a test the mean score was 75% and the standard deviation was 5%. If test scores follow an approximately normal distribution, answer the following questions:
- If a student earned 87 on the test, what is that student’s z-score and what does it mean?
\(\mu = 75\), \(\sigma = 5\), and \(x = 87\)
\(z = \dfrac{x-\mu}{\sigma}\)
\( = \dfrac{87-75}{5}\)
\(=2.40\)
This means that the score of 87 is more than two standard deviations above the mean, and so it is considered to be an unusual score.
- If a student earned 73 on the test, what is that student’s z-score and what does it mean?
\(\mu = 75\), \(\sigma = 5\), and \(x = 73\)
\(z = \dfrac{x-\mu}{\sigma}\)
\( = \dfrac{73-75}{5}\)
\(=-0.40\)
This means that the score of 73 is less than one-half of a standard deviation below the mean. It is considered to be a usual or ordinary score.
- If a student earned 54 on the test, what is that student’s z-score and what does it mean?
\(\mu = 75\), \(\sigma = 5\), and \(x = 54\)
\(z = \dfrac{x-\mu}{\sigma}\)
\( = \dfrac{54-75}{5}\)
\(=-4.20\)
The means that the score of 54 is more than four standard deviations below the mean, and so it is considered to be an unusual score.
- If a student has a z-score of 1.43, what actual score did she get on the test?
\(\mu = 75\), \(\sigma = 5\), and \(z = 1.43\)
This problem involves a little bit of algebra. Do not worry, it is not that hard. Since you are now looking for x instead of z, rearrange the equation solving for x as follows:
\(z = \dfrac{x-\mu}{\sigma}\)
\(z \cdot \sigma= \dfrac{x-\mu}{\cancel{\sigma}} \cdot \cancel{\sigma}\)
\(z \sigma= x - \mu\)
\(z\sigma + \mu = x - \cancel{\mu} + \cancel{\mu}\)
\(x = z\sigma + \mu\)
Now, you can use this formula to find x when you are given z.
\(x = z\sigma + \mu \)
\(x = 1.43 \cdot 5 + 75 \)
\(x = 7.15 + 75 \)
\(x = 82.15 \)
Thus, the z-score of 1.43 corresponds to an actual test score of 82.15%.
- If a student has a z-score of -2.34, what actual score did he get on the test?
\(\mu = 75\), \(\sigma = 5\), and \(z = -2.34\)
Use the formula for x from part d of this problem:
\(x = z\sigma + \mu \)
\(x = -2.34 \cdot 5 + 75 \)
\(x = -11.7 + 75 \)
\(x = 63.3 \)
Thus, the z-score of -2.34 corresponds to an actual test score of 63.3%.
The Five-Number Summary for a Normal Distribution
Looking at the Empirical Rule, 99.7% of all of the data is within three standard deviations of the mean. This means that an approximation for the minimum value in a normal distribution is the mean minus three times the standard deviation, and for the maximum is the mean plus three times the standard deviation. In a normal distribution, the mean and median are the same. Lastly, the first quartile can be approximated by subtracting 0.67448 times the standard deviation from the mean, and the third quartile can be approximated by adding 0.67448 times the standard deviation to the mean. All of these together give the five-number summary.
In mathematical notation, the five-number summary for the normal distribution with mean and standard deviation is as follows:
Five-Number Summary for a Normal Distribution
\(min = \mu - 3\sigma\)
\(Q_{1} = \mu - 0.67448\sigma\)
\(med = \mu \)
\(Q_{3} = \mu + 0.67448\sigma\)
\(max = \mu + 3\sigma\)
Example \(\PageIndex{3}\): Calculating the Five-Number Summary for a Normal Distribution
Suppose that your class took a test and the mean score was 75% and the standard deviation was 5%. If the test scores follow an approximately normal distribution, find the five-number summary.
The mean is \(\mu = 75 \%\) and the standard deviation is \(\sigma = 5 \%\). Thus, the five-number summary for this problem is:
\(min = 75 - 3(5) = 60 \%\)
\(Q_{1} = 75 - 0.67448(5)\approx 71.6 \%\)
\(med = 75 \% \)
\(Q_{3} = 75 + 0.67448(5)\approx 78.4 \%\)
\(max = 75 + 3(5) = 90 \%\)


4.1: Introduction
Climb into your car. Put on your seatbelt. Choose your destination and then…relax. That’s right. You don’t have to do anything else because you are in an autonomous car, or one that navigates its way to your destination! No cars are fully autonomous at the moment and so you theoretically still need to have your hands on the wheel. Self-driving cars may help ease traffic congestion, prevent accidents, and lower pollution. The technology is thanks to computer programmers who are developing software to control the navigation of the car. These programmers rely on their understanding of mathematics, including relationships between equations. In this chapter, you will learn how to solve systems of linear equations in different ways and use them to analyze real-world situations.


2.1: Floating to Moon
At that moment there came to me the happiest thought of my life . . . for an observer falling freely from the roof of a house no gravitational field exists during his fall . . .
Albert Einstein
will the astronaut stand on the floor—or float?
Less than a month after the surrender at Appomattox ended the American Civil War (1861-1865), the French author Jules Verne began writing A Trip From the Earth to the Moon and A Trip Around the Moon . Eminent American cannon designers, so the story goes, cast a great cannon in a pit, with cannon muzzle pointing skyward. From this cannon they fire a ten-ton projectile containing three men and several animals (Figure \(\PageIndex{1}\)).
Jules Verne: Passenger stands on floor
As the projectile coasts outward in unpowered flight toward Moon, Verne says, its passengers walk normally inside the projectile on the end nearer Earth (Figure \(\PageIndex{2}\)). 1 As the trip continues, passengers find themselves pressed less and less against the floor of the spaceship until finally, at the point where Earth and Moon exert equal but opposite gravitational attraction, passengers float free of the floor. Later, as the ship nears Moon, they walk around once again — according to Verne — but now against the end of the spaceship nearer Moon.
Early in the coasting portion of the trip a dog on the ship dies from injuries sustained at takeoff. Passengers dispose of its remains through a door in the spaceship, only to find the body floating outside the window during the entire trip (Figure \(\PageIndex{1}\)).
Paradox of passenger and dog
This story leads to a paradox whose resolution is of crucial importance to relativity. 2 Verne thought it reasonable that Earth's gravitational attraction would keep a passenger pressed against the Earth end of the spaceship during the early part of the trip. He also thought it reasonable that the dog should remain next to the ship, since both ship and dog independently follow the same path through space. But since the dog floats outside the spaceship during the entire trip, why doesn’t the passenger float around inside the spaceship? If the ship were sawed in half would the passenger, now "outside," float free of the floor?
Our experience with actual space flights enables us to resolve this paradox (Figure \(\PageIndex{2}\)). Jules Verne was wrong about the passenger's motion inside the unpowered spaceship. 3 Like the dog outside, the passenger inside independently follows the same path through space as the spaceship itself. Therefore he floats freely relative to the ship during the entire trip (after the initial boost inside the cannon barrel). True: Earth's gravity acts on the passenger. But it also acts on the spaceship. In fact, with respect to Earth, gravitational acceleration of the spaceship just equals gravitational acceleration of the passenger. Because of this equality, there is no relative acceleration between passenger and spaceship. Thus the spaceship serves as a reference frame relative to which the passenger does not experience any acceleration.
To say that acceleration of the passenger relative to the unpowered spaceship equals zero is not to say that his velocity relative to it necessarily also equals zero. He may jump from the floor or spring from the side - in which case he hurtles across the spaceship and strikes the opposite wall. However, when he floats with zero initial velocity relative to the ship the situation is particularly interesting, for he will also float with zero velocity relative to it at all later times. He and the ship follow identical paths through space. How remarkable that the passenger, who cannot see outside, nevertheless moves on this deterministic orbit!  How could one do better at eliminating detectable gravitational influences?
1 Jules Verne: Passenger stands on floor
2 Paradox of passenger and dog
3 Reality: Passenger floats in spaceship


8.0: Introduction
Before the 2021 WNBA season, professional basketball player Candace Parker signed a contract with the Chicago Sky, which entitled her to a salary of $190,000. This amount was the 23rd highest in the league at the time. How did the team’s management decide on her salary? They likely considered some intangible qualities, like her leadership skills. However, much of their deliberations probably took into account her performance on the court. For example, Parker led the league in rebounds in the 2020 season (214 of them) and scored 14.7 points per game (which ranked her 18th among all WNBA players). Further, Parker brought 13 seasons of experience to the team. All of these factors played a role in deciding the terms of her contract.


12.9A: Organization of Motor Neuron Pathways
The motor system is the part of the central nervous system that is involved with movement.
- Describe the organization of motor neuron pathways
Key Points
- The pyramidal tract, which includes both the corticospinal and corticobulbar tracts, serves as the motor pathway for upper motor neuronal signals coming from the cerebral cortex and from primitive brainstem motor nuclei.
- Peripheral motor nerves carry the motor impulses from the spinal cord to the voluntary muscles.
- The large majority (90%) of motor neurons cross (decussate) to the contralateral side of the brain at the level of the brainstem.
Key Terms
- extrapyramidal system : A biological neural network that is part of the motor system that causes involuntary movements.
- corticospinal tract : The nervous system tract that conducts impulses from the brain to the spinal cord. It contains mostly motor axons and is made up of two separate tracts in the spinal cord: the lateral corticospinal tract and the anterior corticospinal tract.
- motor system : The part of the central nervous system that is involved with movement. It consists of the pyramidal and extrapyramidal systems.
- cerebral cortex : The gray, folded, outermost layer of the cerebrum that is responsible for higher brain processes such as sensation, voluntary muscle movement, thought, reasoning, and memory.
Decussation of the pyramids : A deep dissection, lateral view of a brainstem. The pyramidal tract is visible in red, and pyramidal decussation is labeled at lower right.
The motor system is the part of the central nervous system that is involved with movement. It consists of the pyramidal and extrapyramidal system.
The motor pathway, also called the pyramidal tract or the corticospinal tract, serves as the motor pathway for upper motor neuronal signals coming from the cerebral cortex and from primitive brainstem motor nuclei. There are upper and lower motor neurons in the corticospinal tract.
The motor impulses originate in the giant pyramidal cells (Betz cells) of the motor area, i.e., the precentral gyrus of the cerebral cortex. These are the upper motor neurons of the corticospinal tract. The axons of these cells pass from the cerebral cortex to the midbrain and the medulla oblongata. Peripheral motor nerves carry the motor impulses from the anterior horn to the voluntary muscles.
Cortical upper motor neurons originate from Brodmann areas 1, 2, 3, 4, and 6, then descend into the posterior limb of the internal capsule, through the crus cerebri, down through the pons, and to the medullary pyramids, where about 90% of the axons cross to the contralateral side at the decussation of the pyramids. They then descend as the lateral corticospinal tract.
These axons synapse with lower motor neurons in the ventral horns of all levels of the spinal cord. The remaining 10% of axons descend on the ipsilateral side as the ventral corticospinal tract. These axons also synapse with lower motor neurons in the ventral horns. Most of them will cross to the contralateral side of the cord (via the anterior white commissure) just before synapsing.
Brodmann areas of the brain : This drawing shows the regions of the human cerebral cortex as delineated by Korvinian Brodmann on the basis of cytoarchitecture.
The midbrain nuclei include four motor tracts that send upper motor neuronal axons down the spinal cord to lower motor neurons. These are the rubrospinal tract, the vestibulospinal tract, the tectospinal tract, and the reticulospinal tract.
The function of lower motor neurons can be divided into two different groups: the lateral corticospinal tract and the anterior corticalspinal tract. The lateral tract contains upper motor neuronal axons that synapse on the dorsal lateral lower motor neurons, which are involved in distal limb control.
The anterior corticospinal tract descends ipsilaterally in the anterior column, where the axons emerge and either synapse on ventromedial lower motor neurons in the ventral horn ipsilaterally or descussate at the anterior white commissure where they synapse on ventromedial lower motor neurons contralaterally.
The ventromedial lower motor neurons control the large, postural muscles of the axial skeleton. These lower motor neurons, unlike those of the dorsal lateral, are located in the ventral horn throughout the spinal cord.
Spinal cord tracts : This diagram of spinal cord tracts shows the motor and efferent pathways in red and the sensory and afferent pathways in blue. Included in the diagram are the following motor pathways: corticospinal tracts (pyramidal tract), and extrapyramidal tracts (tectospinal tract not delineated).


 This epistemology is interdisciplinary in nature utilizing biology,medical research, sociology and psychology. The science of human sexuality approaches understanding as multilayered. Pulling from these varying disciplines, the field is able to look at sexuality from multiple lenses. While there have been many approaches to the study, its foundation lies in the heteronormative white male perspective. As exclusionary as its roots are,there is an ongoing demand from scholars in the field and much has been written about the need to be more expansive. Understanding Human Sexuality in its totality demands a wider lens.
Whether it was biology or medical research or any of the disciplines that fall under the wide umbrella of an interdisciplinary approach to Human Sexuality, there is a tendency towards an explanation of human sexuality in terms of a false binary that informs the creation of knowledge in the field which is often scientifically inaccurate. Repercussions of this result in varying levels of invalidation of lived experiences of students in the field to highly abusive practices in research and medicine. Historically, the field of Human Sexuality int he United States has been chronically underfunded due to the puritanical roots inherent in the White Anglo-Saxon Protestant (WASP) foundation. Particularly, the study of female or non-binary bodied persons and research findings, stated conclusions, and best practices about sexuality have often been determined with a white, misogynistic, heteronormative lens.
There have been well documented examples of ethical violations that stem from both individual and structural racism reaching back to the development of the field up until present day. We begin this section with the case of enslaved woman, Sara Baartman. Today she is seen by many as the epitome of colonial exploitation and racism, of the ridicule and commodification of Black bodies. Sarah Baartman was brought to Europe seemingly on false pretenses by a British doctor, stage-named the "Hottentot Venus." She was paraded around "freak shows" in London and Paris, with crowds invited to look at her large buttocks. Baartman died on 29 December 1815, but her exhibition continued. Her brain, skeleton and sexual organs remained on display in a Paris museum until 1974. Her remains weren't repatriated and buried until 2002(Parkinson, 2016).
Dr. J. Marion Sims has been heralded as the father of modern gynecology.  He did so by practicing on slave women without the use of anesthesia which clearly raises questions regarding Dr. Sim’s medical ethics and his perceptions surrounding the human rights of enslaved persons. During Simm's tenure, women suffered horribly from this condition and a race for the cure was critical. Dr Sims' use of slave women was well documented historically. By the very nature of their enslavement, these women were unable to consent. He performed surgery on them as test cases, and then performed more surgeries later on some white women without anesthesia.
The use of anesthesia was new during this time, and anesthesia did not become commonplace until he was routinely performing this procedure on white women. (Wall, 2006).He later described white women complaining of pain while enslaved Black women did not, and used this anecdotal evidence to make assumptions about differing pain thresholds as inherently based on race,rather than other possible factors for their differing responses, such as enslaved women’s likely fear of punishment for expressing said pain. Some argue it is not because Dr.Sims was racist, but rather that anesthesia was not widely used; however, whatever biases Simms had about pain thresholds and racial identity allowed him to make assumptions about how the women he worked on experienced the procedures.
There is much controversy surrounding the practices of Dr. Sims and the ethical considerations factoring in despite the invention’s historical significance. A Vesicovaginal Fistula (VVF), rendered women greatly incapacitated during the time Dr. Sims was in practice. It was considered a fate worse than death for many. Prior to Dr. Sims’s breakthrough there had been no consistently effective procedure to repair the fistula and there was not a field of gynecology per se at the time; in fact, examining women’s organs was considered repugnant by male doctors. From 1845-1849, Dr. Sims performed experimental surgery on 7 enslaved Black women in his small backyard hospital (Ojanuga, 1993). He performed his experimental surgery on his first patient Lucy in front of 12 male doctors watching as she crouched on her hands and knees and endured the hour long procedure without anesthesia. The surgery was a failure and she almost died. Another patient, an enslaved woman named Anarcha endured 13 operations without anesthesia with limited success (Ojanuga, 1993). Dr. Sims attempted his procedure on white women but as previously mentioned, found that they could not endure the pain. In the minds of many who look at the history of this particular doctor and his practices, Dr. Sims was not merely a product of his time but rather his infliction of pain on Black women was unethical,cruel and callous.
Sadly, the pattern of white male doctors who callously practice unethical procedures on women and people of color does not end with Dr. Simms. Well into the 21st century, forced sterilization of women in California correctional institutions was a consistent practice (Jindia,2020).
A state audit and prison records reveal nearly 1,400 sterilizations between 1997 and 2013. In addition to people sterilized during labor, an unknown number of cis women and trans people were sterilized during other abdominal procedures (Jindia, 2020).
These sterilizations took place without consent or under coercive circumstances. Despite ethical mandates and procedural efforts to make sure research participants are protected, there remain recent examples of gross violations. As we take a look at these,we often find that marginalized populations are the ones most at risk. There seems to almost be permission to test on incarcerated people like they are lab rats. From high risk cancer treatments, to testing skin cream and cosmetics, they have been used for non-consensual medical testing as if their human rights are not valid. These forced sterilizations of incarcerated women in California prisons are the topic of the new documentary, BELLY OF THE BEAST . This film highlights the ways in which the lives of incarcerated people are not their own, and basic human rights to choose and autonomy of their bodies were grossly disregarded. But it is not just the incarcerated, the institutionalized as well have been sterilized against their will. A recent expose highlighted the decades long practice of forced sterilization and castration of men and women who were living in the Sonoma home, one of many homes for the mentally ill/disabled that practiced this type of forced medical intervention (Barber, 2021). The decisions by medical directors to undertake these sterilizations were based solely on their prejudiced attitudes towards the people whose care they were charged with. The unfortunate truth is that white supremacy, sexism and ableism were deeply entrenched in the mindsets of the medical community that made these decisions without consent and this influences the science and decision making practices of the medical community to this day.
Just as the enslaved women could not consent, incarcerated and institutionalized people face similar lack of rights and threat of increased sentences if they fail to comply with authority. The legacy of structural racism, sexism and heteronormativity are part and parcel of the field of Human Sexuality. It is the hopes of this author that a deeper dive will be undertaken by the readers to explore the ways in which what is otherwise a rich field that’s value stretches far beyond the walls of the academy has to reckon with it’s problematic past and present.


9.30: Polling Tools
- Discuss when and how to use polling tools
In a meeting that has lots of people in various locations and several agenda items to accomplish, it can be a little scary to make sure you have all the details nailed down. Sending an email saying “what do you need?” not only can yield answers from “a flip-chart and markers” to “six webcams and a tap dancing iguana,” it’s also hard for you as the meeting planner to keep track of all the moving parts: schedule, topics, equipment, menu, location.
Conducting an online poll among your team members lets you collect all the information in one place and it gives you control over limiting the options. For example, if you are asking about equipment and supplies, you can choose to list only those items that are reasonable and easy to find. If you’re asking whether a meeting requires video chat, you can ask where people will be joining from. “Switzerland,” “the factory in Omaha” or “home with a broken ankle” are valid reasons for video chat. “Simultaneously watching Game of Thrones on my iPad” is not.
But you can also use polling to get an anonymous take on more serious issues around meetings.
Let’s look at a hypothetical situation in which polling tools might be useful not just in deciding whether you serve pizza or burritos at the meeting but also in handling a challenging agenda item:
Shawn is a regional manager for a clothing retailer. He wants to have a meeting to share the results of some shop-alongs conducted in eight stores in his region by a qualitative researcher and a set of loyal customers. Most of the news is good, but there are a few issues to fix. Some of these issues are systemic and will require input from all his store managers. Others are limited to two specific stores and are concerning because they show those stores are not meeting basic customer service standards.
Shawn decides to send his own summary of the report to the store managers prior to a conference call, specifying the problems but not which stores have them, and asking managers to brainstorm on solutions in advance. Then he starts to plan his meeting agenda. He can envision this meeting playing out in a few different ways, and he can’t quite make up his mind how to proceed.
- Does he focus only on the positives and the systemic issues in this meeting and save the store-specific problems for one-on-one calls?
- Does he talk about the store-specific issues as a group, allowing the other managers to offer suggestions and support to the managers of the struggling stores?
Since all the managers have his summary, he decides to give them a say in how the meeting is run. He creates an account in SurveyMonkey, and he goes through the steps of making a survey.
The basic rules of survey creation are pretty simple at this level, and the software makes it easy.
- Ask as few questions as possible while still getting the needed information.
- Ask only questions that related to the issue at hand. Don’t ask questions just because you’re curious or want to provoke your respondents.
- Phrase questions in a way that gives a full range of options and doesn’t “beg the question.” That is, don’t ask a question like, “How much do you hate plaid pants?” and then give a ranking from “More than a root canal” to “About the same as a hangnail.” The plaid pants-lovers of the world will not be pleased.
- Think about the best question type for what you need to learn. In the scenario above, Shawn decided he really wanted to know how intensely his store managers felt about the agenda issues, so he chose a Ranking question to help them express it. He asked this same kind of question about “problems we face as a region” and “issues at individual stores.”
- He also wanted to give people an opportunity to express their feelings in their own words, especially if they didn’t want to talk about a topic, so he created a Comment question.
- Finally, he figured he would directly ask how bad news should be discussed. He had some ideas of his own, but he also wanted to be open to approaches he hadn’t thought of. For this, he used a Multiple Choice question type with a final Other option with a text box.
As you can see, a well-constructed poll or survey can really help a meeting host or leader plan for everything from snacks to serious issues.
Contributors and Attributions
- Polling Tools. Authored by : Barbara Egel. Provided by : Lumen Learning. License : CC BY: Attribution


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