1. Pollution Chemicals or other harmful items that end up in the air, on land, or in the water and that make the environment unhealthy

2. Trash can become pollution. Flagler Beach, October 9, 2004 Photo credit: Jerry Full

3. Cars and other vehicles can cause air pollution. Photo credit: EnvironmentBlog, Flickr

4. Smog is a type of air pollution. Photo credit: Steven Buss, Flickr

5. Oil spills cause pollution. Photo credit: Russian Doors/Marine Photobank 1 LN HTD KYSTVERKET/Marine Photobank

6. Light can be considered pollution. Photo credit: NASA

7. Sound (loud noise) can be pollution. Photo credit: Purestock, ThinkStock.com

8. Sewage can cause pollution. Photo credit: Steve Spring, Marine Photobank

9. Pollution can be invisible—we cannot see fertilizer and pesticides. Photo credit: Chesapeake Bay Program, Flickr

10. Hot water can be pollution. Photo credit: FPL/Nuclear Regulatory Commission, Flickr

11. How does pollution get into the water? Heavy rain washes things from the land into places like lakes, rivers, and oceans. We call this “stormwater.” Photo credit: Chesapeake Bay Program, Flickr

12. Polluted or Healthy? Sometimes it is easy to tell…sometimes it is harder. Photo credits: Maia McGuire

13. How can we keep our water and air healthy? Recycle Throw trash away properly Ride a bicycle or walk instead of driving a car Use solar or wind energy instead of energy from power plants Photo credit (clockwise from top): Eyematrix, Wavebreakmedia Ltd, jehsomwang, iriselmo; Thinkstock.com