In order to do anything, energy has to be expended. And, of course, we humans do a lot. In this exercise we will examine some of the energy sources that people use, and the impact of their use on the world around us.

Some terms to remember:

By definition, we need to expend energy to do work. For most of history, the only energy resource (other than fire for cooking and heating) was muscle (human and animals (for cultures with beasts of burden). Some cultures also used wind (sailing, windmills) and water (boating, water wheels). But these latter two are limited in availability (either time or place).

Steam power was known since at least classical time: heat up water, and it turns to steam, which can push against surfaces or wheels to move gears and levers. Later, use steam to turn turbines and generate electricity: this is how coal and nuclear fission plants work, for instance. Burning wood is sufficient for low level steam activity, but really effective steam power needs greater concentrations of energy.

Coal, fuel of the Industrial Revolution:

Petroleum (gasoline and natural gas resources), fuel of the modern age:

Renewable Resources (solar, wind, water, geothermal, etc.):

Nuclear Fission:

Potential future resources

Fuel Cell technology:

Nuclear Fusion, Energy of the Future (and may always be!):

We will come back to the issue of future energy resources and utilization in far more detail in the third semester.