23.12: Inductance
Learning Objectives
By the end of this section, you will be able to:
- Calculate the inductance of an inductor.
- Calculate the energy stored in an inductor.
- Calculate the emf generated in an inductor.
Inductors
Induction is the process in which an emf is induced by changing magnetic flux. Many examples have been discussed so far, some more effective than others. Transformers, for example, are designed to be particularly effective at inducing a desired voltage and current with very little loss of energy to other forms. Is there a useful physical quantity related to how “effective” a given device is? The answer is yes, and that physical quantity is called inductance .
Mutual inductance is the effect of Faraday’s law of induction for one device upon another, such as the primary coil in transmitting energy to the secondary in a transformer. See Figure , where simple coils induce emfs in one another.
In the many cases where the geometry of the devices is fixed, flux is changed by varying current. We therefore concentrate on the rate of change of current, \(\Delta I/\delta t\), as the cause of induction. A change in the current \(I_1\) in one device, coil 1 in the figure, induces an \(I_2\) in the other. We express this in equation form as
\[emf_2 = - M\dfrac{\Delta I_1}{\Delta t},\] where \(M\) is defined to be the mutual inductance between the two devices. The minus sign is an expression of Lenz’s law. The larger the mutual inductance \(M\), the more effective the coupling. For example, the coils in Figure have a small \(M\) compared with the transformer coils in [link] . Units for \(M\) are (V\cdot s)/A = \Omega \cdot s\), which is named a henry (H), after Joseph Henry. That is, \(1 \, H = 1 \, \Omega \cdot s\).
Nature is symmetric here. If we change the current \(I_2\) in coil 2, we induce an \(emf_1\) in coil 1, which is given by
\[emf_1 = -M \dfrac{\Delta I_2}{\Delta t},\] where \(M\) is the same as for the reverse process. Transformers run backward with the same effectiveness, or mutual inductance \(M\).
A large mutual inductance \(M\) may or may not be desirable. We want a transformer to have a large mutual inductance. But an appliance, such as an electric clothes dryer, can induce a dangerous emf on its case if the mutual inductance between its coils and the case is large. One way to reduce mutual inductance \(M\) is to counterwind coils to cancel the magnetic field produced. (See Figure .)
Self-inductance , the effect of Faraday’s law of induction of a device on itself, also exists. When, for example, current through a coil is increased, the magnetic field and flux also increase, inducing a counter emf, as required by Lenz’s law. Conversely, if the current is decreased, an emf is induced that opposes the decrease. Most devices have a fixed geometry, and so the change in flux is due entirely to the change in current \(\Delta I\) through the device. The induced emf is related to the physical geometry of the device and the rate of change of current. It is given by
\[emf = -L \dfrac{\Delta I}{\Delta t},\] where \(L\) is the self-inductance of the device. A device that exhibits significant self-inductance is called an inductor , and given the symbol in Figure .
The minus sign is an expression of Lenz’s law, indicating that emf opposes the change in current. Units of self-inductance are henries (H) just as for mutual inductance. The larger the self-inductance \(L\) of a device, the greater its opposition to any change in current through it. For example, a large coil with many turns and an iron core has a large \(L\) and will not allow current to change quickly. To avoid this effect, a smal \(L\) must be achieved, such as by counterwinding coils as in Figure .
 To illustrate this, consider a device with \(L = 1.0 \, H\) that has a 10 A current flowing through it. What happens if we try to shut off the current rapidly, perhaps in only 1.0 ms? An emf, given by \(emf = -L(\Delta I/\Delta t)\), will oppose the change. Thus an emf will be induced given by \(emf = -L(\Delta I/\Delta t) = (1.0 \, H)[(10 \, A)/(1.0 \, ms)] = 10,000 \, V\). The positive sign means this large voltage is in the same direction as the current, opposing its decrease. Such large emfs can cause arcs, damaging switching equipment, and so it may be necessary to change current more slowly.
There are uses for such a large induced voltage. Camera flashes use a battery, two inductors that function as a transformer, and a switching system or oscillator to induce large voltages. (Remember that we need a changing magnetic field, brought about by a changing current, to induce a voltage in another coil.) The oscillator system will do this many times as the battery voltage is boosted to over one thousand volts. (You may hear the high pitched whine from the transformer as the capacitor is being charged.) A capacitor stores the high voltage for later use in powering the flash. (See Figure .)
It is possible to calculate \(L\) for an inductor given its geometry (size and shape) and knowing the magnetic field that it produces. This is difficult in most cases, because of the complexity of the field created. So in this text the inductance \(L\) is usually a given quantity. One exception is the solenoid, because it has a very uniform field inside, a nearly zero field outside, and a simple shape. It is instructive to derive an equation for its inductance. We start by noting that the induced emf is given by Faraday’s law of induction as \(emf = -N(\Delta \Phi /\Delta t)\) and, by the definition of self-inductance, as \(emf = -L(\Delta I/\Delta t)\). Equating these yields
\[emf = -N\dfrac{\Delta \Phi}{\Delta t} = -L \dfrac{\Delta I}{\Delta t}.\]
Solving for \(L\) gives \[L = N\dfrac{\Delta \Phi}{\Delta I}.\]
This equation for the self-inductance \(L\) of a device is always valid. It means that self-inductance \(L\) depends on how effective the current is in creating flux; the more effective, the greater \(\Delta \phi /\Delta I\) is.
Let us use this last equation to find an expression for the inductance of a solenoid. Since the area \(A\) of a solenoid is fixed, the change in flux is \(\Delta \Phi = \Delta (BA) = A\Delta B\). To find \(\Delta B\), we note that the magnetic field of a solenoid is given by \(B = \mu_0 n I = \mu_0 \frac{\Delta I}{l}\). (Here \(n = N/l\), where \(N\) is the number of coils and is the solenoid’s length.) Only the current changes, so that \(\Delta \Phi = A \delta B= \mu_0 NA \frac{\Delta I}{l}\). Substituting \(\Delta \Phi\) into \(L = N \frac{\Delta \Phi}{\Delta I}\) gives
\[L = N\dfrac{\Delta \Phi}{\Delta I} = N \dfrac{\mu_0 NA \frac{\Delta I}{l}}{\Delta I}.\]
This simplifies to \[L = \dfrac{\mu_0 N^2 A}{l} (solenoid).\]
This is the self-inductance of a solenoid of cross-sectional area \(A\) and length \(l\). Note that the inductance depends only on the physical characteristics of the solenoid, consistent with its definition.
Example \(\PageIndex{1}\): Calculating the Self-inductance of a Moderate Size Solenoid
Calculate the self-inductance of a 10.0 cm long, 4.00 cm diameter solenoid that has 200 coils.
Strategy
This is a straightforward application of \(L = \frac{\mu_0 N^2 A}{l}\), since all quantities in the equation except \(L\) are known.
Solution
Use the following expression for the self-inductance of a solenoid:
\[L = \dfrac{\mu_0 N^2 A}{l}.\]
The cross-sectional area in this example is \(A = \pi r^2 = (3.14...)(0.0200 \, m)^2 = 1.26 \times 10^{-3} \, m^2\), \(N\) is given to be 200, and the length \(l\) is 0.100 m. We know the permeability of free space is \(\mu_0 = 4\pi \times 10^{-7} \, T \cdot m/A\). Substituting these into the expression for \(L\) gives
\[L = \dfrac{(4\pi \times 10^{-7} \, T \cdot m/A)(200)^2(1.26 \times 10^{-3} \, m^2)}{0.100 \, m}\]
\[= 0.632 \, mH.\]
Discussion
This solenoid is moderate in size. Its inductance of nearly a millihenry is also considered moderate.
One common application of inductance is used in traffic lights that can tell when vehicles are waiting at the intersection. An electrical circuit with an inductor is placed in the road under the place a waiting car will stop over. The body of the car increases the inductance and the circuit changes sending a signal to the traffic lights to change colors. Similarly, metal detectors used for airport security employ the same technique. A coil or inductor in the metal detector frame acts as both a transmitter and a receiver. The pulsed signal in the transmitter coil induces a signal in the receiver. The self-inductance of the circuit is affected by any metal object in the path. Such detectors can be adjusted for sensitivity and also can indicate the approximate location of metal found on a person. (But they will not be able to detect any plastic explosive such as that found on the “underwear bomber.”) See Figure .
Energy Stored in an Inductor
We know from Lenz’s law that inductances oppose changes in current. There is an alternative way to look at this opposition that is based on energy. Energy is stored in a magnetic field. It takes time to build up energy, and it also takes time to deplete energy; hence, there is an opposition to rapid change. In an inductor, the magnetic field is directly proportional to current and to the inductance of the device. It can be shown that the energy stored in an inductor \( E_{ind}\) is given by
\[E_{ind} = \dfrac{1}{2}LI^2.\]
This expression is similar to that for the energy stored in a capacitor.
Example \(\PageIndex{1}\): Calculating the Energy Stored in the Field of a Solenoid
How much energy is stored in the 0.632 mH inductor of the preceding example when a 30.0 A current flows through it?
Strategy
The energy is given by the equation \(E_{ind} = \frac{1}{2}LI^2\), and all quantities except \(E_{ind}\) are known.
Solution
Substituting the value for \(L\) found in the previous example and the given current into \(E_{ind} = \frac{1}{2}LI^2\) gives
\[E_{ind} = \dfrac{1}{2}LI^2\]
\[0.5(0.632 \times 10^{-3} \, H)(30.0 \, A)^2 = 0.284 \, J.\]
Discussion
This amount of energy is certainly enough to cause a spark if the current is suddenly switched off. It cannot be built up instantaneously unless the power input is infinite.
Summary
- Inductance is the property of a device that tells how effectively it induces an emf in another device.
- Mutual inductance is the effect of two devices in inducing emfs in each other.
- A change in current \(\Delta I_1/\Delta t\) in one induces an \(emf_2\) in the second: \[emf_2 = - M\dfrac{\Delta I_1}{\Delta t},\] where \(M\) is defined to be the mutual inductance between the two devices, and the minus sign is due to Lenz’s law.
- Symmetrically, a change in current \(\Delta I_2/\Delta t\) through the second device induces an \(emf_2\) in the first: \[emf_1 = -M\dfrac{\Delta I_2}{\Delta t},\] where \(M\) is the same mutual inductance as in the reverse process.
- Current changes in a device induce an emf in the device itself.
- Self-inductance is the effect of the device inducing emf in itself.
- The device is called an inductor, and the emf induced in it by a change in current through it is \[emf = -L\dfrac{\Delta I}{\Delta t},\] where \(L\) is the self-inductance of the inductor, and \(\Delta I/\Delta t\) is the rate of change of current through it. The minus sign indicates that emf opposes the change in current, as required by Lenz’s law.
- The unit of self- and mutual inductance is the henry (H), where \(1 \, H = 1 \, \Omega \cdot s.\)
- The self-inductance \(L\) of an inductor is proportional to how much flux changes with current. For an N-turn inductor, \[L = N\dfrac{\Delta \Phi}{\Delta I}.\]
- The self-inductance of a solenoid is \[L = \dfrac{\mu_0 N^2A}{l}(solenoid),\] where \(N\) is its number of turns in the solenoid, \(A\) is its cross-sectional area, \(l\) is its length, and \(\mu_0 = 4\pi \times 10^{-7} \, T \cdot m/A\) is the permeability of free space.
- The energy stored in an inductor \(E_{ind}\) is \[E_{ind} = \dfrac{1}{2} LI^2.\]
Glossary
- inductance
- a property of a device describing how efficient it is at inducing emf in another device
- mutual inductance
- how effective a pair of devices are at inducing emfs in each other
- henry
- the unit of inductance; \(1 \, H = 1 \Omega \cdot s\)
- self-inductance
- how effective a device is at inducing emf in itself
- inductor
- a device that exhibits significant self-inductance
- energy stored in an inductor
- self-explanatory; calculated by \(E_{ind} = \frac{1}{2} LI^2\)
Contributors
Paul Peter Urone (Professor Emeritus at California State University, Sacramento) and Roger Hinrichs (State University of New York, College at Oswego) with Contributing Authors: Kim Dirks (University of Auckland) and Manjula Sharma (University of Sydney). This work is licensed by OpenStax University Physics under a Creative Commons Attribution License (by 4.0) .


2.9: Cultural Health
Assessing cultural health involves gathering data on factors related to a person’s cultural background that may influence their health and illness status.
An open-ended question allows the client to share what they believe to be most important. For example, you may ask, “I am interested in your cultural background as it relates to your health. Can you share with me what is important about your cultural background that will help me care for you?”
It is best to let clients spontaneously answer this question. Give them time to think. You should explore further any factors that they choose to share (e.g., “Tell me more.” “How does that affect your health and illnesses?” “Is there anything else you want to share about how these factors act as resources in your life?”)
Assessing cultural health once meant having a checklist about different cultural groups. This approach is antiquated because it assumes culture is static and measurable. It is important to encourage each client to speak about what is important to them. You may find that clients speak about information related to how they grew up and their way of life, their values and beliefs, traditions related to food, their spirituality or religion, among many other things.
It is important to let the client tell you their cultural health information without interruption or assumption.


28.3: Shapes and Energies of Molecular Orbitals
If we analyze the optimized coefficients of the occupied MOs reported in Equation 29.2.10 , we observe that the lowest energy orbital (by a lot!) is a nearly pure oxygen \(1s\) orbital since the coefficient of the oxygen \(1s\) basis function is very nearly 1 and all other coefficients are rather close to 0. Note, however, that the coefficient is not really a percentage measure. That’s because the basis functions are not necessarily orthogonal to one another. Let’s consider the next molecular orbital up, number 2. It has a dominant contribution from the oxygen \(2s\) basis function, but non-trivial contributions from many other basis functions as well. In order to understand which kind of orbital it is, it is useful to try to visualize some of its properties. For example, recall that the square of the orbital at a particular point in space represents a probability density. As such, we can map values of the square of each orbital on a grid in 3-dimensional space, and then pick a value of probability density, say \(0.04\; a_0^{-3}\), and plot that as a contour surface (remember that a probability density is a 4-dimensional quantity, so we need to take a slice at some constant density to be able to plot it in 3-D). That surface is called an “isodensity” surface. In addition to the square of the function, we can also regions where the wave function is positive blue and regions where it’s negative red. The five occupied and two unoccupied MOs mapped from their one-electron wave functions are plotted in figuere \(\PageIndex{1}\).
Going back to the Lewis structure of water as taught in general chemistry courses, it says that there is one pair of electrons in one O–H \(\sigma\) bond, one pair in another identical such \(\sigma\) bond, and two equivalent pairs that constitute the lone pairs on oxygen. The two lone pairs and the O–H bonds should by pointing towards the apices of a tetrahedron because they are all considered to be \(sp^3\) hybridized.
As you can see, the MOs look nothing like the Lewis picture. Instead, amongst other details, there is one lone pair that is pure \(p\) (not \(sp^3\)), another that is, if anything, \(sp^2\)-like, but also enjoys contribution from hydrogen \(1s\) components. There is one orbital that looks like both O–H \(\sigma\) bonds are present, but another that has an odd “bonding-all-over” character to it.
Is it really possible that for something as simple as water all the things you’ve ever been told about the Lewis structure are wrong? Water must have two equivalent lone pairs, right?
It turns out that the molecular orbital results can be tested with spectroscopic experiments, and suffice to say, they agree perfectly.
But the \(sp^3\)-hybridized picture of water works well, for example, to explain its hydrogen-bonding behavior: In liquid water each water molecule makes two hydrogen bonds to other water molecules and accepts two more from different water molecules and the final structure has a net lattice-like form that is tetrahedral at each oxygen atom. How can the above MOs explain that? The key point to remember is that another molecule does not see the individual orbitals of water, it just sees the final effect of all of those electrons and nuclei together . To explain the tetrahedral H-bond lattice we can plot some constant level of electron density (i.e. $0.02) and map onto this isodensity surface the values of the electrostatic potential. We can find these values by bringing a positive test charge onto that surface and recording how much would it find itself attracted (because of a net negative electrostatic potential) or repelled (because of a net positive electrostatic potential). This is done in figure \(\PageIndex{2}\). Notice how the negative potential is entirely on the oxygen side and the positive potential entirely on the hydrogens side. Moreover, the negative potential splays out to the tetrahedral points and the positive potential does too (those points for the purple region being roughly where the H atoms are).


9.10: Methods of Onboarding
- Evaluate various methods of onboarding
Onboarding approaches range from formal, structured programs to a hands-off policy, where employees are left to figure out cultural norms, organization dynamics and performance expectations on their own. As would be expected, research shows that organizations that engage in a formal onboarding process are more effective than those that don’t. Research shows that effectiveness translates to both employee productivity and retention. In a SHRM article titled “Don’t Underestimate the Importance of Good Onboarding,” author and career counselor Arlene Hirsch cited the following statistics [1] :
- Organizations with a standard onboarding process experienced 50% greater new-hire productivity
- New employees who went through a structured onboarding program were 58% more likely to be with the organization after three years
- New employees who experienced a great onboarding process were 69% more likely to stay with a company for three years
For perspective on best practices, consider L’Oreal: The global beauty company’s onboarding process consists of a two-year, six-part integration program called “L’Oreal Fit.” The stated aim: “to develop successful, committed and mutually beneficial relationships with each of our employees.” [2]
The L’Oreal Fit program includes:
- Training and roundtable discussions
- Meetings with key insiders
- On-the-job learning supported by line management
- Individual mentoring and HR support
- Field and product experiences such as site visits and shadowing programs.
Author, speaker and marketing instructor Stan Phelps refers to onboarding as the first step in employee engagement, noting that “there is no better place to start applying G.L.U.E. (giving little unexpected extras). His premise: “employees are the key drivers of customer experience and that ‘Happy Employees Create Happy Customers.’” [3] In a draft version of his book on employee engagement, Phelps highlights examples of companies who are getting onboarding right.
One of the companies that Phelps mentions briefly is W.L. Gore & Associates, who assigns every new associate a sponsor who is responsible for coaching and mentoring the new employee and it committed to his or her success.
For perspective on the mentoring point (also an aspect of L’Oreal’s onboarding program), SHRM’s online editor/manager Roy Maurer cited research by the Aberdeen Group that found that “high-performing organizations are nearly two-and-a-half times more likely than lower-performing employers to assign a mentor or coach during the onboarding process.” [4]
Another company profiled is custom t-shirt company CustomInk, who uses the onboarding process to both demonstrate and reinforce culture. On arrival, new employees are given a blank journal to record their onboarding experiences, observations and any questions. They are also asked to record instances that illustrate Customlink’s values in action. After 30 days, the new employees gather to share their findings. As Phelps notes: “making new hires accountable for noticing how their colleagues and managers live those values every day helps bring those behavior to life.” [5]
A final example is commercial maritime software provider Veson Nautical, who uses online tools to facilitate the assimilation process. The company’s “FastStart” program uses an online tool that allows managers and new employees to rank or score relevant job-related skills and guides the manager and employee through a discussion of differences. As Sarah Taffee, the company’s director of human resources and organization effectiveness explains: “The actual score doesn’t matter. It’s purely a way of getting up to speed quickly and building the relationship quickly.” [6] For additional perspective on onboarding and employee engagement, view Phelp’s SlideShare presentation titled “ Green Goldfish—Beyond Dollars: 15 Ways to Drive Employee Engagement .” [3]
BambooHR’s Peterson recommends that human resource management check-in with new employees on regular intervals—specifically, one-month and 3-6 months—to ensure that the new employee is thriving. This is also an opportunity to provide feedback. A second check-in is advised prior to the end of six months—a significant stay or leave decision point.  [7] Although different companies have different timetables, employees are expected to be fully up to speed by the end of their first year and the training emphasis is likely to shift to continuous learning and development and career management.
-
Hirsch, Arlene. "
Don't Underestimate the Importance of Good Onboarding
." Society for Human Resource Management. August 10, 2017. Accessed July 17, 2019. ↵
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Sunny, Akash. "Onboarding New Employees: Maximizing Success." Medium. July 1, 2019. Accessed July 17, 2019. ↵
-
Phelps, Stan. "
Green Goldfish – Beyond Dollars: 15 Ways to Drive Employee Engagement and Reinforce Culture
." LinkedIn SlideShare. March 25, 2013. Accessed July 17, 2019. ↵
-
Maurer, Roy. "
New Employee Onboarding Guide
." Society for Human Resource Management. Accessed July 17, 2019. ↵
-
Phelps, Stan. "Green Goldfish – Beyond Dollars: 15 Ways to Drive Employee Engagement and Reinforce Culture." ↵
-
Berg, Jackie. "
8 More Onboarding Programs We Love
." Brilliant Ink. August 15, 2016. Accessed July 17, 2019. ↵
-
Maurer, Roy. "New Employee Onboarding Guide." Society for Human Resource Management. ↵
Contributors and Attributions
- Untitled. Authored by : You X Ventures. Provided by : Unsplash. Located at : https://unsplash.com/photos/Oalh2MojUuk . License : CC0: No Rights Reserved . License Terms : Unsplash License
- Untitled. Authored by : StockSnap. Provided by : Pixabay. Located at : pixabay.com/photos/people-girls-women-students-2557396/. License : CC0: No Rights Reserved . License Terms : Pixabay License


20.7: Develop and Select Instructional Materials
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Based on the instructional strategy for each learning outcome, and information from the other steps of the instructional design process, you need to determine whether materials should be gathered or developed. The main reason for using existing materials (those owned by your institution or purchased) is to save time and money.
Gather Existing Material
Some but likely not all of the needed material may exist. Potential resources can be found in learning-object repositories, other Internet resources such as Wikipedia, and on DVD-ROMs. Learning-object repositories may be found within your institution or at provincial/state, national, and international sites. Compare any existing material to the instructional strategy. Determine whether it is suitable and cost-effective. You may prefer existing materials if the content you would develop will be obsolete before or soon after you complete it. You may have to deal with the “if we didn’t make it, it can’t be any good” syndrome.
Determine whether the existing material can be adapted or supplemented. One alternative is to get permission to repurpose existing materials for your own needs. Remember, if you include work done by others, you may not have permission to earn money from your product. However, you may be able to work out a revenue-sharing agreement.
Note that not all copyrights will be cleared, and some promised materials might not be provided.
Remember to check all digital materials for viruses.
Develop the Needed Material
The instructional strategy of the materials you develop should consider the learning domain, motivational techniques, each event of instruction, and all of the information gained through the systematic instructional design process. It is wise to create a paper-based version (storyboard) of what will appear on each screen that a student will see. The screen sample is shown in Figure \(\PageIndex{1}\). Storyboards are easier to review and edit than content within a learning management system.
Note
Thoroughly evaluating a storyboard can help prevent the team from wasting a significant amount of time making revisions.
The storyboard must be written and designed for the computer screen. If this is not done well, time must be spent adapting the material. If possible, follow standardized specifications to help with consistency. Consistency is important as it makes it easier for learners to learn. A lack of consistency can lead to learner frustration. Attain consistency by using design templates but ensure that the templates do not inhibit creativity or compromise learning.
Leave room for visuals on the screen or insert digitized images and try to estimate the amount of text that is reasonable for each screen. A problem with trying to exactly match storyboards to computer screens is that the video images, visuals, and text can take more or less space than expected. It is not necessary to have the media at this point. For example, text and dialogue scripts can describe what video and audio will contain while text can be used to describe photographs.
Initially work with one typical learning outcome and evaluate the storyboard before continuing with other learning outcomes. This helps prevent problems from being perpetuated throughout a course. After the entire storyboard is written, distribute the storyboard or pin it up and ask for feedback from other subject-matter experts, especially others who will use the product, and from potential learners. Thoroughly evaluate the material for flow, clarity, accuracy, completeness, pace, interaction, and length. As a general rule, if the storyboard has problems, then the material will have problems when it is transferred to the learning management system. Remember that the final version will be inherently better when the media is added.
Note
If you develop, review, and revise one learning outcome at a time, you can prevent problems from being copied throughout the course.
Expect to make revisions. After the first learning outcome has been transferred to the computer, thoroughly evaluate it. After revisions have been made, continue developing subsequent learning outcomes and lessons. Repeat the revision and evaluation process as often as is needed for each learning outcome, group of learning outcomes, and lesson.
Based on the storyboard, make final decisions about the media needed to effectively teach the material. These decisions are based on what will most effectively teach the material as well as practical considerations such as cost and available expertise. Once you make the decisions, start creating the media. You must consider the file formats that will be used and where the media will be stored, such as DVD-ROM, CD-ROM, Internet, or intranet. (Practical considerations for this and media selection are presented in Chapter 21, Multimedia.)
A final storyboard must be created for the person who transfers the material to the learning management system. An accurate storyboard will reduce the number of subsequent revisions needed. After you develop the media, individual pieces can be incorporated into the system. After this, you can begin the final formative evaluation.
The components of a complete instructional multimedia package can also include:
- an easy-to-use student manual with directions, strategies, learning outcomes, and summaries
- remedial and enrichment material
- an easy-to-use instructor’s manual


7.1: Introduction
Introduction
By the 1970s, the cold war between the United States and European nations against the Soviet Union caused political and economic issues worldwide, bringing the advent of the Cold War. After World War II, many of the Eastern European countries were under the control and rule of the Soviet Union. Although both the United States/European alliance and the Soviet Union were theoretically at peace, the entire period was dominated by the arms race, including nuclear, proxy wars, and sociopolitical bids around the globe for world dominance. The United States was focused on the potential spread of communism, a concept ruling the political discourse and conflicts in America and indiscriminate wars abroad. By 1970, the space race was well underway as both the United States and the Soviet Union made space exploration part of the Cold War. Part of the space race was the development of missiles capable of space travel, and more ominously, giving the countries the ability to launch nuclear warheads into other countries.
After World War II and the successful expulsion of Japan from China, the civil war in China began. The Nationalist government led by Chiang Kai-shek was attacked by the Communist leader Mao Zedong. By 1949, the communist forces won, and Mao Zedong was established as the head of China. The Chinese government assisted North Korea and Vietnam in their wars against the United States. By 1971, China was given a seat at the United Nations, official recognition of the country. When President Nixon was elected, his focus was to use diplomacy, and in 1972 the president went to China to start diplomatic relations with a country closed to the world since World War II. Nixon and the Soviets also signed the Strategic Arms Limitation Treaty, the first step to reducing nuclear missiles.
However, President Reagan reversed the ideas of diplomacy and funded insurgencies in other countries, especially Central America. Simultaneously, the Soviet Union experienced severe financial and political disintegration. When Premier Mikhail Gorbachev took office in 1985, he started the concepts of 'glasnost' or political openness and economic restructuring. The Soviet control and influence over the Eastern European countries ended, and by 1991, the Soviet Union fell apart, and the existing Cold War stopped. Many of the former Soviet states established forms of democratic governments. China had strong financial ties with other countries, including the United States, expanding its manufacturing capabilities. The Chinese people began demanding more freedoms culminating in a million students demonstrating in 1989 at Tiananmen Square. The police massacred students, and the government clamped down on their freedoms.
The European Union was formed in 1992, integrating their economic activities and giving more freedom of movement to work and travel across borders. Significant events occurred in different places, including the Oslo Accords, a peace agreement between Israelis and Palestinians, still a tentative process. The North American Free Trade Agreement (Nafta) was signed to bring favorable trade relations between Canada, the United States, and Mexico. In 1994 South Africa, Nelson Mandela, a man who spent years in prison for his work against the apartheid white government, was elected the first black president. And in 1999, the United States transferred control of the Panama Canal to Panama.
By 2000 and the entry to a new century, the world was a global community, with many of the countries able to build a middle class and prosperity. Multiple countries became players in the global field, each establishing their economic fortune and power. However, some countries still lived with persistent poverty, disease, poor economies, and population explosions. The major powers of China, Russia, and the United States are still locked in conflicting struggles for dominance.
Expression of Neo-Expressionism
How people are positioned on the canvas or paper was a discussion and concept for the Neo-Expressionists. They did not focus on the subject itself. Instead, they explored the paint application instead of the content. It was important for the viewer to interface with the colors or lines on the surface. Georg Baselitz turned his images upside down on the canvas to emphasize the shapes or colors. Other artists positioned a person in sections or parts, placing them in random patterns. Graffiti art was popular, and artists used some of the techniques to express a concept with symbols or embodied in shapes. Modern spray paint was an innovation used in graffiti applications and adopted by some Neo-Expressionists like Jean-Michel Basquiat. Basquiat started as an artist spraying graffiti on walls in New York City and used some of the same ideas for his canvases. The artists used forceful brushstrokes, splattered paint, or dark dividing lines. Some of the expressions were almost primitive and frequently criticized societal politics.
Technology of the Video Artists
Video art started in the late 1960s based on the availability of new technology for consumers, including videotape recorders, colored televisions, DVDs, and video cameras. From the 1970s, the technology became cheaper, faster, smaller, and more powerful, allowing more creativity for the artists. Small, hand-held cameras allowed artists to video record, no longer tied to the expensive 8-mm and 16-mm equipment. They were also able to simply remix and combine footage they shot and pre-recorded images from multiple sources. By the 1980s, editing software became affordable for the average person. The software lets the artists program their videos, edit different scenes, and add audio. Artists started to combine Video Art and Performance Art. With the small video cameras, performance might be outside or in a kitchen, freeing anyone to become a performer. The capabilities opening for this new art form because of the advent of small, portable camera recorders formed the same revolution as the Impressionist's ability to paint outside because they had portable paint tubes. Andy Warhol was one of the first artists to use technology on a grand scale when he used a computer system and software to create his digital drawings. Since the 1970s, technology has been intertwined with art, the ever-expanding media bringing continual changes and experiences for artists. The 1990s technology brought the internet and the ability of people to interact, access broader audiences, and manipulate their artwork.
Materials of the Young British Artists
The Young British Artists became a brand name used to market Britain's new and unusual style. The movement began with students at Goldsmiths College of Art when they set up an exhibition called Freeze ; the show became known for its shock tactics based on unusual materials and the way they used materials. The artists frequently used found objects and presented them in different ways. Dada artists incorporated their art around found objects; however, they were conservatively displayed compared to the Young British Artists. The artists used dead preserved animals, their furniture, food of all types, or medicines and pills. The objects were stuffed, crushed, disassembled, or combined into integrated artwork. Artists also used film and photography to create or enhance their work. Some artists went beyond the traditional view of the female body, treating the image outside of the definition of how males defined the beauty of a woman's body.
Forms of Sculpture
Sculpture took many forms with the advent of new technological breakthroughs in materials and the assembly of sculptures. However, one of the most basic forms became popular in this period in the form of Land Art or Environmental Art. The artist interacted with materials found in the natural environment. Land Art celebrated nature, and artists often enhanced nature with other materials, the art was not based on anything except the beauty of nature. Sculptures also went beyond the single figure and made installations frequently based on social issues. Minimalism concepts were found in many forms of sculptures as technology and manufacturing capabilities allowed artists to create shapes and forms that might be considered simple, except the immense size of the installation made a dynamic impact. The ability to roll massive metal sheets, form them, and transport and install them brought stunning sculptures. Other artists of this time used materials previously unheard of, the dead shark representing the symbol of absurdity.


3.1: Why It Matters- Writing Essentials
Why analyze the structure and essentials of writing?
 During drafts, you will identify any holes in your arguments, and look closely at paragraph construction, the introduction and conclusion, and continue to revise the paper until you have a clear and coherent argument.
While you will approach an argumentative essay differently than, say, a narrative essay about a specific event, there are certain features that all of these styles or methods have in common:
- A clear thesis statement, usually provided at the beginning of the essay
- Clear and logical transitions
- Focused body paragraphs with evidence and support
- Appropriate format and style if you use source material
- A conclusion that expands upon your thesis and summarizes evidence
- Clear writing that follows standard conventions for things like grammar , punctuation , and spelling.
In this module, we’ll take a closer look at each of these components of essential writing.
Contributors and Attributions
- Modification, adaptation, and original content. Provided by : Lumen Learning. License : CC BY: Attribution
- Why It Matters: Writing Process. Provided by : Lumen Learning. License : CC BY-NC-SA: Attribution-NonCommercial-ShareAlike
- Really? Writing? Again?. Authored by : Amy Guptill. Provided by : The College at Brockport, SUNY. Located at : textbooks.opensuny.org/writing-in-college-from-competence-to-excellence/. Project : Writing in College: From Competence to Excellence. . License : CC BY-NC-SA: Attribution-NonCommercial-ShareAlike
- Hiker on Dune Ridges at Sunset. Authored by : Great Sand Dunes National Park and Preserve. Located at : https://www.flickr.com/photos/greatsanddunesnpp/35474169820/ . License : CC BY: Attribution
- Rhetorical Styles. Provided by : Excelsior OWL. Located at : https://owl.excelsior.edu/rhetorical-styles/ . License : CC BY: Attribution


10.2: Descriptions of Families
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- Cindy Stephens, Gina Peterson, Sharon Eyrich, & Jennifer Paris
- College of the Canyons via College of the Canyons
Here are descriptions of the types of families listed in Chapter 8.
Dual parent family
We often thing about this as a mother and father raising children. However, in thinking about the the diversity of families this could include same sex parents as they are also raising children together.
Single parent family (either by choice or through divorce)
This could be a male or female parent who either wants to be a parent and does not have a partner to create a child with or is raising children on their own due to divorce. Often, we think of single parents as female, but today as we continue to form acceptance of family structures, they are males who are also choosing to form a family on their own or raise their children (from divorce) on their own.
Grandparents or other relatives raising children (relatives can also be non-related family members who are close to the children)
Children whose parents are not able to care for them (for whatever reason), may be raised by their maternal or paternal grandparents or may be raised by extended family members including those family members that are not related biologically.
Teen parents
Today it is more acceptable for teens who become pregnant to raise a child. Sometimes they may do this together or separate. Sometimes they may do this with the help of their families. Teens who become pregnant while still in high school are often able to return to school and there are programs on high school campuses where teens may bring their child. They may receive parenting classes in addition to their high school curriculum.
Adoptive families (including transracial adoption)
Families who are not able to conceive a child or carry a child to term may choose adoption as a way to form a family. While this tends to be most common, there are families who consciously choose adoption over procreation as well as decide to add to their family through adoption. In any case, forming a family through adoption is a choice not taken lightly. There are many options in forming your family through adoption. You can choose to have an open or closed adoption. Open adoption refers to having a continued relationship with the birth parent(s) to just knowing who the birthparents are and everything in between. Closed adoption means that the family does not have access to birthparent(s) information. In addition, families may choose to adopt a child of the same race or of another race.
Foster families
Children placed in temporary care due to extenuating circumstances involving their family of origin may be placed in homes that are licensed to care for children. The adults who foster these children must go through strict protocols in order to care for these vulnerable children. The most common name for this arrangement is fostering, but you may also hear them described as resource families. In these cases, it is the intent to reunite the children with their family of origin whenever possible. When this is not possible, the children are placed in the system for adoption. The foster family may decide to adopt the children or adopted by another family. It is always the intent to find a permanent arrangement for children whenever possible, as we know that stability has better outcomes for children.
Families with Same-sex parents
Same sex couples, whether two men or two women, may choose to form a family and raise the children together. There are many options available when deciding to form their family. They may adopt, they may use reproductive technology, and they may use egg or sperm donors. In the case where two women are choosing to form a family, one of them may become pregnant and give birth to their child. According to recent research into children raised by same sex parents, there is evidence to suggest that since these children are planned, they often have better outcomes than originally was believed.
Bi-racial/Multi-racial families
These include families with children raised by parents from two different races, including parents who may be bi-racial themselves. This also includes multi-racial families. Society is becoming more acceptable of diversity within families, which provides children with better outcomes.
Families with multi-religious/faith beliefs
This includes families with children raised by parents who have different religious faith/beliefs. They may choose to raise their children with neither religion, either religion, or both.
Children with an incarcerated parent(s)
This includes families where one or both parents are incarcerated. This can be complicated for the family as the parent may spend some time away and then return home. While the parent who is incarcerated is away, the family structure changes. Each time the parent goes away and comes back adds to this confusion. Sometimes, children whose parent(s) are incarcerated may live in foster care while their parent is away and be returned to the parent upon their release, if it is safe for the child to do so.
Unmarried parents who are raising children
Today, many parents are deciding not to marry and raise children. The only difference is that they do not have a legal marriage license; however, their family structure is the same as dual parent families whether opposite sex or same sex.
Transgender parents raising children
This refers to two ways in which children may be raised by a transgender parent or parents. A parent may transition after already having children with someone of the opposite sex or they may transition prior to having a child and decide they want to parent.
Blended families
A blended family can be two different parents that come together each bringing their children from a previous relationship with them. Sometimes the parents that come together with children from a previous relationship may also decide to have a child together.
Multigenerational Families
These are families where multiple generations either live together in the same household or nearby. In America, this was a familiar practice during our agricultural boom. In other countries, this is an accepted practice, especially in Native cultures.
Families formed through reproductive technology
Today we have sophisticated medical advances to help parents who are infertile to become pregnant and give birth to their biological child as well as to use the biological material from someone else and carry that fertilized embryo to term. The variety of reproductive technology available to families is quite expansive. This is often at a huge financial cost to the families, as most medical insurance companies do not cover the medical expenses of infertility.
First time older parents
Today it is becoming more common for men and women to have children in their 30’s, 40’s, and even older.
Families who are homeless
We know that some children are raised without a stable home. The family may be living in their car, living in a hotel, a homeless shelter, or living in multiple dwellings also known as couch surfing. Families experiencing homelessness may be due to the loss of a job/steady income, being employed by making minimal wages that do not provide the means necessary to sustain housing (and other basic necessities), or other issues that may complicate the family’s ability to sustain a stable place to live. Families do not always share their homeless status as there is often shame and embarrassment that society places on these families.
 These delays/disabilities are varied. There also may be typically developing children in the family as well. This often places a burden on families, not only because of the time needed to care for a child who is not typically developing, but because society often misinterprets children who display behaviors that may be viewed as challenging.
Families raising their children in a culture not their own and in which English is not the primary language
This refers to families who may have immigrated here and whose children were either born in their country of origin or born in the United States. This duality of cultures can create challenges for the child and their family if societal expectations are that the family enculturate to the dominant culture. This results in children feeling shame about their family when they should feel pride in their family of origin.


14.1: Rhetoric and Composition/ Exposition
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What is Exposition Writing?
Exposition can be either oral or written. It is used to explain, interpret, inform, or describe. An expository writer must assume that the audience has no prior knowledge regarding the topic being discussed. So the topic must be written in a clear manner explaining how things work (you can however, leave out common knowledge --you probably are not writing for first graders).
As most academic terms, exposition can acquire various definitions depending on the context in which a writer is using the word. The HarperCollins Collins English Dictionary defines exposition in seven different disciplinary contexts.
1. Within the Communication Arts / Journalism & Publishing discipline, exposition is defined as: a systematic, usually written statement about, commentary on, or explanation of a specific subject
2. The act of expounding of setting forth information or a viewpoint
3. (Business / Commerce) of a large public exhibition, especially of industrial products or arts and crafts
4. The act of exposing or the state of being exposed
5. (Performing Arts / Theatre) the part of a play, novel, etc., in which the theme and main characters are introduced.
6. (Music / Classical Music) Music the first statement of the subjects or themes of a movement in sonata form or a fugue
7. (Christianity / Roman Catholic Church) RC Church the exhibiting of the consecrated Eucharistic Host or a relic for public veneration (Harper Collins Dictionary)
Types of Exposition
- Description - The author explains a particular topic by showing characteristics, features, and examples.
- Comparison - The author shows how two or more topics are alike.
- Contrast - The author shows how two or more topics are different.
- Cause and Effect - The author demonstrates the cause while showing the effects of the cause.
- Problem and Solution - The author explains a problem, then explores possible solutions.
- Analytical - The author evaluates a topic or argument revealing its strengths and weaknesses.
- Classification - The author sorts things into useful categories, makes sure all the categories follow a single organizing principle, and gives examples that fit into each category.
- Sequence - The author lists items or events in numerical or chronological order.
Where Do I Begin?
Find a Topic and Research
First you must find a specific aspect of a topic that would interest you. You will have to research the topic extensively so that you can explain it—what exposition is all about. Research your topic extensively. You will probably have to spend quite a bit of time, but remember that the researching can be exciting. The general initial researching may even provide some valuable information that you want to explain. Researching is like exercising: at first it hurts, but with time you become stronger and it's easier to flex your researching muscles. After you have decided upon a topic, you can create a thesis.
Thesis
An expositional paper is most easily written when you have a "tight" thesis. This means that the focus of your topic is extremely specific. When your thesis is concise, you can write at length because you know exactly what you should be writing about. But when you have a sloppy, vague thesis, you can become lost and your writing reflects this. This goes back to choosing a topic focus that deals with something specific, and not overly general. A thesis makes a claim regarding your focus and is supported by details and facts. It is written in one or two complete sentences. An example of a thesis would be: “Gardening can be a rewarding hobby because of the creativity involved, the variety of plants, and the many uses of plants.”
Create a Sketchy Outline
After you write your thesis, create a sketchy outline so that you have a game plan for your paper. Your outline should have information that you want to include for each part of your thesis. For our thesis example, we could find lots of information that could support the different parts of gardening. Notice the word could --just because we have the information doesn't mean we must use it in the paper. This is a rough outline after all.
Start Writing
Too often we don’t begin writing because we are stuck—don’t be, just start writing. You can begin anywhere. Start writing where you feel the most comfortable. When you have your outline, as sketchy as it may be, it reminds you of ideas that you want to include in your paper. Remember though that readers are interested in what YOU have to say—they don’t want to read regurgitated quotes and opinions of others, so make sure that your point is being heard.
Structure
The structure of an expository piece consists of first an introduction that contains the most crucial element—the thesis—the main point you wish to convey. After the introduction is the body, in which you clarify the different aspects of the thesis in great detail. The final piece, the conclusion, restates and rephrases (using different words) the thesis and ties up any “loose ends”.
Introduction
The very first part of your introduction should have an attention-grabbing device (a hook) to engage your readers. Hooks can be statistics, facts, questions, or unusual details. Don't make general statements such as "it is clear that..." because you are trying to explain something that perhaps your reader doesn't know, so it would not be clear to them. Instead be informative. The introduction will also contain your thesis. Good topic referring to Rhetoric. One can check it at the essays writing companies and already written essays accomplished by writing service writers.
Body
Now that you have your specific thesis, along with your sketchy outline, you must support your thesis claim by using concrete evidence and examples. You should exfoliate your thesis. Remember that expositional writing assumes that your readers have no prior knowledge regarding your topic, so you must explain things very clearly. Parallelism can be very important in your paper. It can give the readers a feeling of structure and importance. Pick a method of organization and stick with it.
In our example, we would explain in detail how much creativity is involved in gardening. We could write about the style of impressive European or Oriental gardens. Next, we would show how there are a variety of plants. We could write about plants found in different climates. Finally, we would explain the many uses of plants. We could write about floral bouquets and vegetables.
Because exposition’s purpose is to inform, you will want to establish common ground with your readers. You should write objectively, which will fulfill the purpose of explaining things.
Conclusion
A conclusion wraps up your paper by recalling your main points, but do not use the identical words that you used in your introduction. Conclusions and introductions are like frames, they should tie your whole paper together. You should explain your main points briefly and freshly.
Sample Exposition Assignments
Here are some sample assignments to prepare you for a real exposition paper or essay. Remember that your audience has very little previous knowledge of your topic!
Sample Assignments
- Write an informative exposition essay on the many uses of duct tape.
- Compose a descriptive exposition essay about your room.
- Type an analytical exposition essay that analyzes your computer keyboard and the how effective it is at its job.
- You can also use other subjects to write about, such as your favorite food or drink or your hobbies.
Sample Exposition Essay
Assignment: Explain an aspect of cellular phones.
Sample Exposition Essay
"Words are, of course, the most powerful drug used by mankind;" one of the best ways to spread this "powerful drug" is through the simple act of talking to another person. Everybody wants to talk and everybody also wants to listen and learn. How is one man or woman supposed to communicate with another from across the city, state, or even country without a very powerful tool? This powerful tool, while seemingly simple, is called a cellular phone, or cell phone for short. The cell phone has revolutionized the way that the world communicates with each other and spreads the good word. One might be asking just what a cell phone is--well, listen up and find out. The cell phone has its roots with the telegraph and telephone. These are both devices that are able to send messages through land-based wires called phone lines. That means that a coded message or a voice is sent through phone lines in order to make it to its destination. The receiving person can then translate the code or listen to the voice on the other end. On a telephone, people were capable of having a conversation from across the nation while it sounded like they were in the same room as each other. In order for them to be able to make a call to each other, though, there would have to be a web of phone lines connecting them over thousands of miles of land. Laying all of these phone lines was very cumbersome, as was only being able to send or receive calls from a stationary place, like a house or office. While the Telephone made broad communication more accessible, it still did not have entirely enough freedom for the people. This was all changed in the year 1973. A man named Martin Cooper invented the first Cellular Phone while working for Motorola. It was about the size of a brick and weighed over 30 ounces (or 1.8 pounds). While big in size, it was even larger in potential. Cooper made his first call on his cell phone while walking in the middle of a New York street. There were no wires connected to his phone. There was nothing restricting his movement and could send or receive calls from anywhere. How does a cell phone work if it is not connected to the phone lines? The short answer to that question is: satellites. The cell phone emits a signal to one of the many satellites that are orbiting Earth. The satellite catches the signal and sends it back to Earth to the person that was meant to receive it. This does not mean that cell phones cannot communicate with land-line telephones. If a cell phone calls a land-line, the signal is sent to the satellite and then back to a satellite dish on Earth where it is then re-sent through landlines to the house or office. This also works in reverse for a land-line that is calling a cell phone. The cell phone is much more than just a unwired phone in the present day. It has evolved much since Cooper's phone of '73 and they now weigh an average of 3 ounces. Cell phones can now store all of the phone numbers that a person needs. There is no more having to find the list of phone numbers on a piece of paper and to dial the number every time a call is placed to somebody. With cell phones, one simply just has to find a person's name on the phone and press send. They can even store schedules, set sleep alarms, take pictures, play music, browse the Internet, and much more. The cell phone has come a long way in 30 years to set a world free of wires. There is nothing holding anybody back from walking down the middle of the street while having a conversation with somebody 2000 miles away anymore. The cell phone is a marvel beyond what was imagined when Alexander Graham Bell first invented the telephone. It is a very powerful tool for getting our words around, and will take us places in the future that we have never dreamed of.
- Information in this essay was provided from About.com .
Why Is This Good?
First the introduction, a surprising and interesting quote, immediately catches your attention since it equalizes words and drugs. The introduction has a tight thesis, “The cell phone has revolutionized the way that the world communicates with each other and spreads the good word.”
The body explains the revolution of cell phones. Notice how the writer clearly defined what a phone line is and how it works. The writer transitions into another topic by asking a question, “How does a cell phone work if it is not connected to the phone lines?” Asking questions is an easy rhetorical device that can make your paper flow more smoothly.
Finally, this conclusion ties together the paper since it recalls the main themes. By using different words, the conclusion is fresh and not predictable. It is future looking. “It is a very powerful tool for getting our words around, and it will take us places in the future that we have never dreamed of.”


Love and intimacy go hand in hand. Love is the physical, emotional, sexual, intellectual, or social affection one person holds for another. A thesaurus lists related concepts to love which include adore, desire, prefer, possess, care for, serve, and even worship as similar concepts. Intimacy, on the other hand, is a close relationship where mutual acceptance, nurturance, and trust are shared at some level. In order to understand love in human relationships you must first understand how the self either enhances or inhibits your capacity to love.
You self developed under the watchful eyes of your caregiver or parents. When you were a newborn you were totally dependent upon the adults in your life to take care of your needs and raise you in a safe environment. You had to be fed and clothed, bathed and held, and loved and appreciated.  An attachment is an emotional and social bind that forms between one person and another. Humans are considered highly motivated to form attachments through their lives.
Attachments are crucial to human existence and are essentially the emotional context of those relationships we all have in life. As an infant you learned to trust those who cared for you. You learned that they return once they are out of view and that they can be depended upon. Eventually your brain allows you to love the person you are attached to and to care for them whether or not they are giving care to you. You learn then that your attachments facilitate your needs and wants being met. How you attached as an infant and young child shape (at least in theory) how you will likely attach as an adult. If you had strong attachments in childhood then forming adult relationships should be easier for you. If you had weak or interrupted attachments in childhood then forming adult relationships-especially loving ones will be more difficult for you.
As adults, one of the very first symptoms that you are falling in love is that you begin to feel better about yourself when you are with the other person. One of my students commented in class, “That's true for my boyfriend and me. We started off just hanging out with mutual friends. Then we were talking a lot on the phone. But, both us felt that feeling of wanting to be together more often and feeling good, you know safe together.”
It can be argued that you can only be in love as much as your self will allow you to be.
Why? Because intimacy develops along with love and intimacy requires that you have the ability to be your true self with the other person. Figure 1 shows what I call the “Zone of Vulnerability,” or the birthplace of intimacy. The photos of the young man and woman in this figure represent you and your other and how you traverse the dangers of getting to know someone while you enter and reside in the zone of vulnerability. The guy and gal in this figure as total strangers to one another enjoy a certain safety that comes by keeping safely away from relationships, away from personal conversations, and away from any risks of being hurt (or hurt again).
She or he can go to classes, work, social events, even on dates and never leave her or his private comfort zone. It doesn't take much to mask the fact that you are hiding safely away from risks even when outwardly you appear to be very confident and socially skilled (watch the Movie “Hitch, 2005 with Will Smith, Eva Mendes, and Kevin James).
But, if and when intimacy and love enters the equation, you have to leave your safety zone. Typically when two strangers meet they self-disclose. Self-disclosure is the process or revealing the true nature of oneself to another person. Once you or the other person open up and share something vulnerable (see the blue arrow in the diagram) you enter an emotional mine field of sorts. You become at risk. Your fears and pains from past relationships, your feelings of being emotionally vulnerable or naked, and especially your fears of being exposed as a flawed individual all sift the process of you letting the other person sneak a peek into the nature of your true self.
This sifting process is shaped by countless interactions with others that preceded this moment in time. The sifting through past experience can make it very risky for some.
But, once you self-disclose the potential for intimacy and love can be realized. There is a greater chance of intimacy developing when the other person self-discloses back to you, or reciprocates your efforts to connect. For example, let's say that the guy and gal in this figure had their pictures taken so that they could submit them to the university cheer squad tryouts. On the day of tryouts they meet one another for the first time and make casual conversation in the registration line.
During tryouts they are assigned to team up to perform a series of lifts. Circumstances have brought them together, but intimacy is typically more deliberate. He might ask,
“Where did you cheer in high school?”
She might tell him the school name and place then ask, “What about you?” At this level of questioning, just talking is mildly risky, but they are only talking at a level called Shop Talk, which is safe conversation about superficial things (places, time, weather, etc.). If she came back with a question of her own such as, “What do you think the chances are we make the team?” she has begun a conversation about opinions and feelings.
He might reply, “I think we have as good a chance as the others. I hope we both make it.
Hey, uh, you sound like your really need this to happen.”
“Yeah, I need the scholarship and I'm majoring in dance so it will help me keep in shape.” What about you?”
“Oh, I'm majoring in pre-law. The scholarship would be great, too. Hey, would you like to go get a juice or something…”
In this example, their shop talk quickly transformed into the mutual sharing of personal information. This is essential for intimacy to have a chance to form. Perhaps, if they feel safe enough over time and with a number of interactions they can become very close and trusting of one another as friends or lovers. Nice that it works that way sometimes, but truth be known we more often miss than hit when forming intimate relationships.
Consider what might have happened if the conversation went like this: He might ask,
“Where did you cheer in high school?” She might tell him the school name and place.
Then continue packing her things making no more comments. “My name is Jeff. What's yours?” He might ask, extending his hand to shake. “Melisa. Good luck with the tryouts.” As she walks away not shaking his hand nor making eye contact. Because mutual involvement did not occur, intimacy stopped before it every really had a chance.
Remember, once self-disclosure take place the risk factor comes into play. If self-disclosure is mutually reciprocated then intimacy may begin. If it is not reciprocated then intimacy typically will not develop. We are built to experience love. Psychologists and Biologists will tell you that best friends or not chemicals either reinforce feelings of love or inhibit them. Our attractions are connected to our testosterone, oxytocin, luteinizing, estrogens, serotonin, dopamine, epinephrine, norepinephrine, and other chemicals and hormones levels in our bodies. Sociologists will tell you that the need for social relationships, especially attachments, drive much of our daily social interactions with others. Theologians will tell you that love is divine and is part of our eternal natures.
Psychologists have taken a variety of approaches in the study of love. John Lee is perhaps the most quoted researcher on love with his six love types. Lee assumed that we all shared 6 core components of love and that our current loving relationship can be assessed and measured. Lee also claimed that there are qualities of love types-some more long-lasting and supportive of relationships and some pathological and defective which inhibit relationships (see Lee, John, A (1988) ALove Styles@ in The Psychology of Love; Sternberg, R. & Barnes, M eds. New Haven CT: Yale U. Press). Lee's love types are widely used to help people understand their love styles. Lee claimed that six types of love comprised our loving experiences. Eros is the love of sensuality, sex, taste, touch, sight, hearing, and smell. Eros love is often what we feel when turned on. Eros love is neither good nor bad. It is simply part of the overall love composite we experience with another person.
Storgé love is the love of your best friend in a normal casual context of life. Storgé is calm and peaceful, surprising to some who might have simply hung out together at one point but suddenly discovered that their friendship deepened and became more important than other friendships. “We started needing to be together, talking on the phone for hours, and missing each other when apart,” are common descriptions of Storgé love.
Many believe that most young couples marry with Storgé relationship in the US today.
Pragma love is the love of details and qualities in the other person. Pragma lovers are satisfied and attracted by the other because of their characteristics (e.g., athleticism, intelligence, wealth, etc.). Pragma lovers feel love at a rational level-thinking to a certain degree about the good deal they are getting in the relationship.
Agapé love is the love that is selfless, other-focused, and seeks to serve others rather than receive from others. Lee referred to a Christian love when originally wrote the chapter cited above. Since then this type of love can be identified across cultures and religions.
Lee identified to defective love types that come from a damaged sense of self: Ludis and Mania.
Ludis is an immature love that is more of a tease than a legitimate loving relationship.
Ludic lovers trick their mates into believing that they are sincerely in love, while all the while grooming 1, 2, or even 3 other lovers at the same time. Ludic lovers artificially stroke their sense of self-worth by laying a cruel game on their lovers who end up feeling used and betrayed. Mania is an insecure love that is a mixture of conflict and artificially romantic Eros expressions. Manic lovers are horrified of being abandoned and simultaneously terrified by the vulnerabilities they feel when intimate with their lover.
Thus their daily routines are typically make out…argue…sweet talk…slap fight…make out…verbal yell fest…make love…stop talking…sweet talk…break up…make out…
Another psychologists named Abraham Maslow addressed love in terms of how our needs are met by the other person. His basic premise is that we pair of with those whose love style fills an unmet childhood need. In other words, Maslow said that if our childhood needs were not met in the basics of survival, safety, food, shelter, love, belonging, and even self-esteem then we look for an adult companion that can fill those needs for us. It's like an empty cup from our childhood that our adult partner fills for us.
Maslow also said that when all those basic needs are met in childhood then we are attracted to an adult partner who compliments our full development into our psychological potential (Google Maslow's pyramid of Hierarchy of Needs, Being and Deficiency love). If in your childhood your survival, safety, food, shelter, love, belonging, and even self-esteem needs were unmet then you will be attracted to a Deficiency Lover. A Deficiency Lover is a lover who provides the basic level of needs for their partner while having their needs reciprocally met in a similar way. A Being Lover meets you aesthetic, intellectual and full actualization or human capacity needs while you reciprocally meet their in a similar way.
Robert Sternberg was the Geometry of Love psychologists who triangulated love using intimacy, passion, and commitment on the 3 corners of the triangle and by measuring the intensity of each and how intense it was for the couple. To Sternberg it was important to consider how each partner's triangle matched the other partner's. He said that a couple with all three types of love, balanced and in sufficient magnitude would have a rare yet rewarding type of love that encompassed much of what couple seek for in a loving relationship (Google Robert Sternberg, Triangular Theory of Love, Consummate Love).
Sternberg's Consummate Love was a love type that had equal measures of passion, intimacy, and commitment that is satisfactory to both lovers.
A popular psychologist named Gary Chapman spoke of the culture of our love and addressed love the same way you or I met address how you'd prepare travel to or live in another country. You wouldn't just up and go to Mexico without first familiarizing yourself with the language customs and traditions. In the same line of reasoning, you would be wise when you fall in love to study the other person's culture of expressing love and then study your own. Chapman spoke of how we express verbal love, love in physical touch, love through service, love by spending quality time together, love by receiving gifts given to us by those who love us (See Gary Chapman The Five Love Languages, How to Express Heartfelt Commitment to Your Mate).
In a less-modern and scientific approach to love, philosophers and writers have addressed love and its origins over the millennia of years. The ancient Greeks spoke of a few types of love that we define similarly in our society today. Eros is the love of the body, touch, senses, and sexual pleasuring. Eros proves in our culture to be a significant part of a long-term relationship. Eros in combination with other love types can be very satisfying to those in intimate relationships. Agape love is a pure love felt at the soul level where one person loves another at a profound level. Agape love may be what we feel for others when we hear about their tragedies, when we hear about their accomplishments, or when we hear about positive normal life events. John Lee drew upon these love types for his work in the US 1970s.
Philia is often referred to as brotherly love (e.g., Philadelphia=city of brotherly love) or love without passion. It addresses the component of love between family members where
needs are mutually met by members of the family. Plato's definition of love (often called Platonic Love) included a nonsexual relationship, that could include deep levels of trust and intimacy and could be found among many types of relationships (couples, families, friends, even strangers, for more information, Google Greek love types, Platonic Love, and/or philosophy of love). Plato gave a test for true love when he claimed that true love will endure over space and time, or when two people are not together for a while.
In modern day applications of love, various components have been found as the ingredients of love: commitment, passion, friendship, trust, loyalty, affections, intimacy, acceptance, caring, concern, care, selflessness, infatuation, and romance. There is a love type identified that many people are aware of called Unconditional Love. Unconditional love is the sincere love that does not vary regardless of the actions of the person who is loved. Unconditional love is so deep and profound that it lets us forgive and still love.
Some of this love type is found in almost all relationships. You often hear it expressed in greater measure among parents of children whose misbehaviors embarrass or make them ashamed. The love types and patterns discussed below are taken form many sources, but fit neatly into the Lee, Maslow, Sternberg, or Chapman paradigms. I urge you to study their original works if you are interested in understanding how love is measured and studies.
Romantic love is based on continual courtship and physical intimacy. Romantic lovers continue to date long after they marry or move in together. They often express the strong sexual attraction to the other that was there from the beginning. Romantic lovers are idealistic about their relationship and often feel that it was destined to be. They often define mundane activities such as grocery shopping or commuting into work as escapades of two lovers.
What happens when very young people feel love for the first time? What is puppy love or infatuation? Infatuation is a temporary state of love where the other person is overly idealized and seen in narrow and extremely positive terms. An infatuated person my think obsessively about the other, may feel a strong emotional response when they are together, may see their entire world as revolving around the other, may see them being together for the rest of their lives, may find one or two qualities of the other as being near perfect, or may be seen by others as having a crush on the other person. Regardless of the details infatuations rarely last very long. This love develops quickly much like a firework launches quickly into the night sky, puts on an emotional light show, then burns out quickly. Many define puppy love or infatuation as an immature love experienced by those who are younger and perhaps a bit gullible.
Committed love is a love that is loyal and devoted. Two lovers may share committed love with or without physical affection, romance, friendship, trust, loyalty, acceptance, caring, concern, care, selflessness, and or infatuation. Committed lovers have a long-term history with one another and typically combine caregiving, concern for one another's well-being, and spending much time thinking of the other. Committed lovers are there when needed by the other person.
Altruism is a selfless type of love that serves others while not serving the one who is altruistic. True altruism is hard to find according to some. Many find similarities in the Greek Agapé and altruism. The world's major religions each have a version of altruism
One elderly woman told me that when she was younger you never could have convinced her that the flu could help build her loving relationship to her husband. She said when she was in her 50s she caught a really bad version of the flu and was nearly hospitalized during the worst part of it.  “He stood in front of me while I was on the toilette and held me up, even though I was vomiting. He did this so that I could hold on to what little dignity I had left. After each episode he carefully bathed me and helped me get some sleep.
When I finally recovered I realized that my love for him grew dramatically during this illness, because he took care of me and never asked for so much as a thank you for having done it.” Her husband expressed that his love grew even more than hers during this illness.
Sexual or Passionate lovers are focused on the intensely sensual pleasures that are found with the senses of taste, smell, touch, feel, hear, and sight. Sexual lovers lust one another and feel closest when together and being physical. Sexual lovers can be together for 5
minutes, 5 days, five weeks or five years, but sexual love, by itself typically is short-lived. There is closeness during sex and activities leading up to sex, but not much thereafter. Sexual love when combined with other love types can be very beneficial to the couple. Sexual love is almost always the love type experienced by those having an extra-marital affair.
Friendship love includes intimacy and trust among close friends. In our day, most long-burning or enduring love types form among people who were first close friends.
Friendship lovers tend to enjoy each other's company, conversation, and daily interactions. They consider one another to be “go to” friends when advice is needed or when problems need to be talked about together. Not all friendship lovers become a couple. Many are just close or best friends. Yet, many who spend the rest of their lives together will start out their relationship as friends.
Criteria or realistic love is the love feelings you have when your list of a potential mate's personal traits is met in the other person. Women often desire their man to be taller. Men and women often desire to find a partner with homogamous traits (e.g., same religion, political leanings, hobbies, etc.). I personally had a friend who always said he would marry a red head. He did. I have another friend who said he'd never marry a thin woman and he didn't. Each of us has an ideal for a partner and we tend to get some of those characteristics with people we become intimate with and eventually marry.
Obsessive love is an unhealthy love type where conflict and dramatic extremes in the relationship are both the goal and the theme of the couple's love. Obsessive lovers live for storms and find peace while they rage. They are often violent or overly aggressive at
different levels. A few couples bring complimentary traits to the relationship which light the other's fire of madness if you will. In other words, she may be angry and violent with him, but not with some other guys. He may feel simultaneously drawn to her and repulsed, but not with other gals. Their personality chemistry contributes to the insanity and lack of peace. Please note, these couples most likely need professional counseling and would probably be better off if they broke up immediately and never saw one another again. At the same time, why would they seek help or leave the person whose entanglements bring them such an occupation with drama and conflict that they are freed from their boredom and entertained at the same time.
Finally there is deceptive love. Deceptive love is formed when one or both partners either consciously or unconsciously mislead the other in an effort to dishonestly establish trust and intimacy. This love type follows a “catch and release” or a “black widow/widower” mode. In the catch and release mode one partner lures the other in by pretending to experience all the romance and trappings of falling in love when in reality he or she is tricking the other person. The trickery is done in a never-ending pursuit of many relationships all of which are initially established and most of which are ultimately never maintained. In other words, he is more interested in falling in love and catching more fish (lovers) than in staying in love and maintaining a long-term relationship. The catch and release love may not be aware of the unhealthy nature of his or her antics.
In the black widow/widower mode there is calculated and precise deception designed to lure the other into a relationship for ulterior motives. The deceiver tricks the other in order to gain access to wealth, property, or even power. The victim in this relationship often discovers too late that he or she was taken advantage of and that he or she has been deceived. The catch and release lover sometimes deceives him or herself, whereas the black widow/widower lover is fully aware of their deception and their ultimate goals.
Among all these love types lies an underlying truth mentioned before-loving is a risky business where hurt feelings and pain are far too common and wounds and scars from past relationships haunt some long after they form a permanent relationship. Part of that haunting past for lovers is unrequited love. Unrequited love is the result of one person deeply wanting and intimate relationship with another who simply is not interested and does not reciprocate. Unrequited love is common among younger lovers who misread verbal and nonverbal cues and who often have yet to learn about their own love needs and wants.
Understanding love is crucial in the United States because the majority of our population needs to fall in love before they marry. In other words, love precedes marriage. Outside of the US, in India, China, Africa and other regions of the world, love is hoped for after a couple marries, but not considered as a prerequisite to marriage. In the US we fall in love then marry and conversely fall out of love then divorce. I would argue that falling into love is truly about falling into the Zone of Vulnerability and a safe sense of self in that intimacy. Falling out of love is truly about lost trust, lost safety, and lost self once the relationship has reached a point of trouble.
For very young couples falling into love and finding that safe place for both selves is easy and is often based on fantasy rather than reason and logic. Teens often have mutually self-serving motivations that make their love feel so real and powerful at the time. Look at Figure \(\PageIndex{2}\) below. For many teens who form intimate relationships, the girls are seeking social status and maturity by having a complex relationship with a boy and by demonstrating to her girlfriends her social capabilities. Typically, teen girls seek after love, closeness, intimacy, and the status of being a girlfriend, steady, or even engaged.
That works conveniently for boys who are seeking physical affection and social status.
Take a hypothetical example of Dave who is on the basketball team in high school. He notices that Shiree has been hanging out with his buddies and has asked them details about his availability. His buddies reveal Shiree's interest in him and they eventually sit next to one another at lunch. Eventually Dave and Shiree are “a thing” and they date exclusively. Dave pressures Shiree for more sexual expression together. Shiree is not very interested because she really wants the love and all the relationship benefits that come with it.
Dave becomes more and more interested in sex and soon learns that if he makes gestures toward Shiree and their devotion to one another, then Shiree allows physical things to go further and further. After the prom, flowers, Dave letting Shiree wear his varsity jacket, and a promise ring and guarantee, Shiree and Dave become sexually active. Shiree shows up at Dave's house unannounced and tells Dave's father that she is going to be his daughter-in-law. Dave's father invites her in and brings Dave downstairs for a visit.
Shiree reveals to them that she is pregnant and that Dave and promised/guaranteed her if they got pregnant then they would get married. Dave, upon hearing the news of the pregnancy blurts out, “you are putting that baby up for adoption, I'm too young to be a father!”
Dave was wrong on both claims. Shiree kept the baby, he was the father, and she dumped Dave on the spot. It's been 17 years now that Dave has made monthly child support payments. Shiree married and started a family with another man. Of course this is a true story with names changed to protect identities. But, it is also a very typical story where the girl saw all the trappings of what she thought love was. The guy saw opportunities for pleasure and social status and each experiences a predictable teen love relationship. This pattern helps to explain in part why teens engage in sex at an early age and why teen pregnancy sometimes occurs from that sex. This pattern in Figure 2 has not been found to apply to adults and has not been found to apply to all teen romances.
Adults tend to report more sexual and relational satisfaction when intimacy and friendship are part of the overall relationship.


5: Current and Resistance
In this chapter, we study the electrical current through a material, where the electrical current is the rate of flow of charge. We also examine a characteristic of materials known as the resistance. Resistance is a measure of how much a material impedes the flow of charge, and it will be shown that the resistance depends on temperature. In general, a good conductor, such as copper, gold, or silver, has very low resistance. Some materials, called superconductors, have zero resistance at very low temperatures.
-
- 5.1: Prelude to Current and Resistance
- High currents are required for the operation of electromagnets. Superconductors can be used to make electromagnets that are 10 times stronger than the strongest conventional electromagnets. These superconducting magnets are used in the construction of magnetic resonance imaging (MRI) devices that can be used to make high-resolution images of the human body. Superconducting magnets have many other uses.
-
- 5.2: Electrical Current
- The instantaneous electrical current, or simply the current I, is the rate at which charge flows. The direction of conventional current is taken as the direction in which positive charge moves. In a simple direct-current (DC) circuit, this will be from the positive terminal of the battery to the negative terminal. The SI unit for current is the ampere (the amp). Current consists of the flow of free charges, such as electrons, protons, and ions.
-
- 5.3: Model of Conduction in Metals
- The current through a conductor depends mainly on the motion of free electrons. When an electrical field is applied to a conductor, the free electrons in a conductor do not move through a conductor at a constant speed and direction; instead, the motion is almost random due to collisions with atoms and other free electrons. Although the electrons move in a nearly random fashion, when an electrical field is applied, the overall velocity of the electrons can be defined in terms of a drift velocity.
-
- 5.4: Resistivity and Resistance
- When a voltage source is connected to a conductor, it applies a potential difference V that creates an electrical field. The electrical field, in turn, exerts force on free charges, causing current. The amount of current depends not only on the magnitude of the voltage, but also on the characteristics of the material that the current is flowing through. The material can resist the flow of the charges, and the measure of how much a material resists the flow of charges is known as the resistivity.
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- 5.5: Ohm's Law
- Many materials exhibit a simple relationship among the values for these properties, known as Ohm’s law. Many other materials do not show this relationship, so despite being called Ohm’s law, it is not considered a law of nature, like Newton’s laws or the laws of thermodynamics. But it is very useful for calculations involving materials that do obey Ohm’s law.
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- 5.6: Electrical Energy and Power
- In an electric circuit, electrical energy is continuously converted into other forms of energy. For example, when a current flows in a conductor, electrical energy is converted into thermal energy within the conductor. The electrical field, supplied by the voltage source, accelerates the free electrons, increasing their kinetic energy for a short time. This increased kinetic energy is converted into thermal energy through collisions with the ions of the lattice structure of the conductor.
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- 5.7: Superconductors
- Transmission of electric power produces line losses. These line losses exist whether the power is generated from conventional power plants (using coal, oil, or gas), nuclear plants, solar plants, hydroelectric plants, or wind farms. These losses can be reduced, but not eliminated, by transmitting using a higher voltage. It would be wonderful if these line losses could be eliminated, but that would require transmission lines that have zero resistance.


16.4: Advanced shared symmetric-key methods
Both the substitution and transposition methods discussed so far are shared symmetric-key methods, meaning that both sender and receiver would have to have agreed upon the same secret encryption key before any methods could be sent.
All of the methods so far have been susceptible to frequency analysis since each letter is always mapped to the same encrypted character.  For example, the Enigma machines used in World War II had wheels that rotated. Each wheel was a substitution cipher, but the rotation would cause the substitution used to shift after each character.
For a simplified example, in the initial setup, the wheel might provide the mapping
- Original: \(\mathrm{ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789}\)
- Maps to: \(\mathrm{2BQF5WRTD8IJ6HLCOSUVK3A0X9YZN1G4ME7P}\)
After the first character is encrypted, the wheel rotates, shifting the mapping one space, resulting in a new shifted mapping:
- Original: \(\mathrm{ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789}\)
- Maps to: \(\mathrm{P2BQF5WRTD8IJ6HLCOSUVK3A0X9YZN1G4ME7}\)
Using this approach, no letter gets encrypted as the same character over and over.
Encrypt the message “See me”. Use a basic Caesar cipher with shift 3 as the initial substitution, but shift the substitution one place after each character.
Solution
The initial mapping is
- Original: \(\mathrm{ABCDEFGHIJKLMNOPQRSTUVWXYZ}\)
- Maps to: \(\mathrm{DEFGHIJKLMNOPQRSTUVWXYZABC}\)
This would map the first letter, S to V. We would then shift the mapping by one.
- Original: \(\mathrm{ABCDEFGHIJKLMNOPQRSTUVWXYZ}\)
- Now maps to: \(\mathrm{EFGHIJKLMNOPQRSTUVWXYZABCD}\)
Now the next letter, E, will map to I. Again we shift the cipher
- Original: \(\mathrm{ABCDEFGHIJKLMNOPQRSTUVWXYZ}\)
- Now maps to: \(\mathrm{FGHIJKLMNOPQRSTUVWXYZABCDE}\)
The next letter, E, now maps to J. Continuing this process, the final message would be VIJSL.
Notice that frequency analysis is much less useful now, since the character E has been mapped to three different characters due to the shifting of the substitution mapping.
Decrypt the message KIQRV if it was encrypted using a basic Caesar cipher with shift 3 as the initial substitution, but shifting the substitution one place after each character.
- Answer
-
The initial mapping was:
- Original: \(\mathrm{ABCDEFGHIJKLMNOPQRSTUVWXYZ}\)
- Now maps to: \(\mathrm{DEFGHIJKLMNOPQRSTUVWXYZABC}\)
Using this, we can see the first character of the encrypted message, \(K\), can be decrypted to the letter H. We now shift the mapping by one character.
- Original: \(\mathrm{ABCDEFGHIJKLMNOPQRSTUVWXYZ}\)
- Now maps to: \(\mathrm{EFGHIJKLMNOPQRSTUVWXYZABCD}\)
The second character in the message, I, can be decrypted to the letter E. Continuing this process of shifting and decrypting, KIQRV decrypts to HELLO.
The actual Engima machines used in WWII were more complex. Each wheel consisted of a complex substitution cipher, and multiple wheels were used in a chain[1]. The specific wheels used, order of the wheels, and starting position of the wheels formed the encryption key. While captured Engima devices provided the Allied forces details on the encryption method, the keys still had to be broken to decrypt messages.
These code breaking efforts led to the development of some of the first electronic computers by Alan Turing at Bletchley Park in the United Kingdom. This is generally considered the beginnings of modern computing[2].
In the 1970s, the U.S. government had a competition and ultimately approved an algorithm deemed DES (Data Encryption Standard) to be used for encrypting government data. It became the standard encryption algorithm used. This method used a combination of multiple substitution and transposition steps, along with other steps in which the encryption key is mixed with the message. This method uses an encryption key with length 56 bits, meaning there are 2 56 possible keys.
This number of keys make a brute force attack extremely difficult and costly, but not impossible. In 1998, a team was able to find the decryption key for a message in 2 days, using about $250,000 worth of hardware. However, the price and time will go down as computer power increases.
From 1997 to 2001 the government held another competition, ultimately adopting a new method, deemed AES (Advanced Encryption Standard). This method uses encryption keys with 128, 192, or 256 bits, providing up to 2 256 possible keys, making brute force attacks essentially impossible.
[1] http://en.wikipedia.org/wiki/File:En...abet_rings.jpg
[2] For a good overview, see http://www.youtube.com/watch?v=5nK_ft0Lf1s


15.2: Mozart, Eine kleine Nachtmusik, K. 525, II.
15.2 Mozart, Eine kleine Nachtmusik, K. 525, II.
The second movement of Mozart’s Eine kleine Nachtmusik is a five-part rondo form (ABACA).
Let us examine the elements of music in the first section (the A section).
Notice how Mozart expresses the various musical elements:
| Harmony |
The key is C major |
| Rhythm |
The 8th note is most common rhythmic value, though the phrase begins with quarter-note values |
| Texture |
The top two instruments are grouped together against a simple bass part |
| Articulation |
Generally legato |
| Dynamics | Soft |
| Register |
Neither extremely high nor low |
Here is the beginning of the second section (the B section):
Here are the most noticeable differences:
| Rhythm |
8th notes are the most common rhythmic value, with some 16th-note runs |
| Texture |
All four voices move in the same rhythm at the beginning of each subphrase |
| Articulation |
Four staccato notes start each subphrase |
Now, look at the beginning of the next contrasting section (the C section):
The following elements are noticeably changed:
| Harmony |
This section begins in C minor |
| Rhythm |
The accompaniment moves in 16th notes and the ornamentation of the second melody note (the turn) in the outer parts sounds as four 32nd notes |
| Texture |
The middle two parts (Violin II and Viola) are paired together and the Violin I and Cello/Bass part engage in imitation |
| Articulation |
The middle parts are played in a “separated” manner (more staccato than legato) and the motive in the outer voices starts with a staccato note |
Listen to how Mozart puts the entire form together, including transitional material to smooth out the changes from one section to another.