Many of your students will have difficult with this topic. Energy is a nebulous concept, especially for those students whose backgrounds in the physical sciences is limited.
You might wish to copy and distribute to your students the Overview of Chapter Objectives flowchart found at the beginning of this Instructor's Manual Chapter.
Plan this chapter carefully. Decide beforehand exactly which topics will be needed in the later parts of your course. Also decide how much depth your students will need now, and how much depth can be incorporated into your later lessons. Keep in mind that this is an overview chapter and it can be adapted to meet the needs of your particular class.
If the background of your class is highly heterogenous, I suggest you assign a student-generated annotated outline to be handed in before you lecture on this material. This type of assignment assures that the students work through the material and that they become aware of any specific problems they may have. This also helps you discover the strong and weak points of your class.
Another suggestion is for you to write out a series of questions over the material you specifically have chosen to cover. These questions may or may not be similar to the Mastering Concepts questions found in text or the end of chapter questions found on page 124. Students without a background in this material may become frustrated when trying to write out the answers to the questions. This technique forces the students to dig for information but it also helps you identify what the students do and do not understand.
You can use a very simple, but highly effective, classroom experiment to demonstrate the laws of thermodynamics. I suggest actually doing this experiment, rather than simply asking the students to visualize it. Bring in a clear glass full of warm water and some ice cubes. Without comment at the beginning of the class period, put the ice in the water. Toward the end of class, comment on the ice cubes and ask the students what happened. You can use this as a pivot for discussions on entropy, equilibrium, heat exchange, and the necessity for energy, among other topics.
- IV.C.2. Some students may be confused with the statement that the breakdown of glucose to carbon dioxide and water is spontaneous. After all, a person can sit and watch a glass of glucose for hours and nothing happens. Stress that this is a cascade of events and that energy is required to start the reactions but that once a certain point is passed, the reaction does continue spontaneously and the net result is definitely exergonic. This will be covered in greater detail in the next chapter.
- IV.E. Redox reactions can be confusing because to students it often doesn't make sense to say that reduction gains something. Think of it this way: As a substance gains electrons, its negativity becomes greater; its positivity is reduced. Use the name LEO as a mnemonic -- Lose Electrons Oxidation.
If you decide to spend more time with oxidation/ reduction reactions, you might consider using the accompanying diagram.
Keep in mind that oxidation/ reduction reactions always involve one or more of the following: electrons, hydrogen, oxygen. Most biological oxidation/reduction reactions involve all three.
- VI.A.1&2. Here is a practical example of positive and negative feedback. Suppose the baby is crying. You assume the baby is hungry and give it a bottle. The baby really wanted a clean diaper. The agitation was increased so the crying was even louder. That's positive feedback -- the response increased the stimulus. Suppose the baby really was hungry. The bottle stopped the crying. That's negative feedback -- the response decreased the stimulus.
