1. To demonstrate different types of energy, lift a small object. This object has potential energy. Lift the object over your head. You have increased the object's potential energy. Allow the object to drop to the floor and you have converted this energy to kinetic energy. A large ball of clay works well for this demonstration. Ask where the energy goes when the object is dropped. No energy is ever lost, but is transformed instead. The final form taken by all energy is heat.

2. An alternative demonstration involves the discussion of an automobile and the conversion of chemical energy (in gasoline) to mechanical energy of motion, and heat energy in both the exhaust and from friction produced by the tires on the road.

1. Figure 7.2 demonstrates the fact that molecules hold energy in their bonds.

2. A good way to demonstrate the idea of chemical energy is to burn a substance or to boil a substance (water is easy and shows change of phase as well).

1. To illustrate spontaneous reactions, the melting of ice (though it is not really a reaction) over the course of the class period or the rusting of metal over the course of a semester work very well. Alternatively, dropping an iron nail into a solution of blue copper chloride one day and examining the results (copper on the bottom of the beaker and a brown iron chloride solution) two days later is also effective. These illustrate changes that occur spontaneously, but not instantaneously.

1. Figure 7.4 illustrates the idea that, without intervention, most systems will move toward entropy. The structure falls to disrepair unless energy is also expended.

2. An apparatus could be used to show the electrolysis of water, a reaction that requires energy to break the bonds in the molecule and produce hydrogen and oxygen gas.

1. Figure 7.8 illustrates that organisms are constantly exchanging energy with their environment. The fact that food is consumed (or photons are collected from sunlight) and wastes are left behind illustrates this. Show a picture of someone eating and another picture of someone running.

1. Figure 7.9 presents a metabolic pathway as an assembly line. A mistake at any step in the pathway can change the product irrevocably. The automobile assembly line is probably one with which students are familiar. If one step is skipped or one job performed improperly, the automobile is defective and cannot serve the purpose for which it was constructed.

1. The concept of a food web is easily illustrated with pictures of a pasture, cow, and a farmer. The grasses grow using energy captured from sunlight. The cow eats the grass and uses the energy to grow and reproduce. The farmer eats the meat of the cow and gets energy from the food.

2. Figure 7.19 is an illustration of a food web. Use it or other visuals to represent the flow of energy through an ecosystem. Plants are producers and herbivores are primary consumers. Secondary consumers are animals, as are omnivores that consume animals and plants. Decomposers, like fungi, derive energy from dead animal and plant material.