Power, work, and energy

Power, work, and energy are not things -- we cannot see them directly, but only as actions or processes, by what happens as a result, such as how high a thrown stone gets before it begins to fall. But we can know them and even measure them.

Is it possible to measure the work done by plants, by photosynthesis? How?

Can you find estimates of total global photosynthesis, expressed in watts or horsepower or some other measure? What kinds of observations and measurements are these estimates based on?

Can you find estimates of the total power of all industrial energy used by humans, expressed in watts, horsepower, BTUs, or some other measure? What kinds of observations and measurements are these estimates based on?

Here is a rough diagram of the uses of sunlight reaching earth. What evidence can you find to confirm or question any of these figures?

"Land, then, is not merely soil; it is a fountain of energy flowing through a circuit of soils, plants, and animals." --Aldo Leopold