Micrograph © David Phillips/Visuals Unlimited. Illustration © Eric MacDicken.

You carry millions of microbes on your hands. Most are harmless, but you can pick up some that cause illnesses, such as colds, flu, and diarrhea.

When we forget to wash our hands, or don't wash them properly, we can spread these germs to other people, or give them to ourselves by touching our eyes, mouths, noses or cuts on our bodies.

We can also pick up germs from objects, such as doorknobs and stair railings, touched by other people who aren't good handwashers. Think about all the things you touch each day and how many people may have touched them before you.

You can learn more about what happens when people don't wash well or often enough by reading the Press Release on WashUp.org (scroll down the page to the section labeled Handwashing Fact Sheet near the bottom). Or check out this video on handwashing made by students at River Ridge High School in New Port Richey, Fla. (You can choose the 2.2M high bandwidth version or, if you're using a modem, the 513K low bandwidth version might be a lot faster for you. You'll need the Quicktime player to view these video files. You can download it for free here.)

Handwashing with warm water and soap can greatly reduce the chances of spreading or getting germs. The mechanical action of scrubbing loosens up the dirt and microbes on our hands and the soap picks them up and binds to them so that the water can wash them away.

Go to Experiments to try a fun activity with your friends or family that will show you why handwashing is important.

So when should you wash your hands? Stop and think of the times you wash up each day and then click here to see how well you're doing.