Germs are microbes in the environment which do us harm. They are of two kinds: bacteria and viruses.

Both of these germs give us diseases which we can pass from one person to another. They are called infectious diseases.

Bacteria and viruses are too small to be seen except with a powerful microscope.

Many bacteria and viruses make a kind of surface glue of a material called starch. This helps them to fix on to surfaces and so multiply.

It is very hard to kill these germs, except by using boiling temperatures or above, and as we don't use boiling water to wash our hands, dishes or clothes, what we do mostly is to try to wash germs away.

When we wash our hands (or our dishes, or our clothes) we are using the soap or detergent to dissolve the starch glue or get between it and our skin or clothes and so loosen the germs' grip. We can only do that by rubbing soap or detergent thoroughly. That is why, for example, washing machines tumble clothes about - they are knocking the germs off the clothes (as well as bits of dirt and food etc).

This action is much more effective with bio-type washing powders which contain small materials called enzymes. That is why it is best to use bio-powders.