If you don't do it already, start tossing clean tin cans (e.g. soup, pet food, coffee...

This is the transfer of energy via waves or particles. An example is when heat moves from a warmer object to a cooler one, as from the sun to the Earth. There are two types of radiation-ionizing and non-ionizing. The latter has less energy; it can move atoms around but cannot change their structure. Visible light, radio waves, and microwaves are examples of non-ionizing radiation. Ionizing radiation, on the other hand, is much more powerful. Its energy levels are high enough to remove electrons from atoms, creating charged particles that are called ions. This type of radiation is used to fight cancer and to generate nuclear energy, among other things.

Exposure to ionizing radiation in the environment can be hazardous. This can occur from the inhalation or ingestion of radioactive material (either naturally occurring in soil, rocks, etc., or resulting from industry or other human activity), or by direct exposure to radiation, which primarily occurs when working with radioactive materials. The Environmental Protection Agency (EPA) and other government agencies regulate many sources of radioactive materials to control exposure; it's important to test for naturally occurring sources such as radon, which can present a hazard in homes.

Ever since the Environmental Protection...