CoachGerms are living things far too small to see, which are everywhere — on hands, on door handles, in dirt. Most are harmless, but some can make us ill when they get inside the body. Because they are invisible, hands that look clean can still carry them.
Examples
Example 6.4 (The glitter experiment)
Rub a pinch of glitter on your palms, then shake hands with a friend, open a door, pick up a pencil: glitter everywhere. Germs travel exactly like that, only invisibly. Now wash with soap, counting to — the glitter goes, and so do the germs.