In science we are going over atoms and molecules. Water is made up of two chemicals, hydrogen (H) and oxygen (O). There are two hydrogen molecules for each oxygen so water can be represented as H2O. Now the kids understand why we call water H20.
It made it easy for them to understand when I explained that a single water molecule is typically drawn looking a bit like Mikey Mouse with green hydrogen ears and a purple face: (we used grapes)
They spent a good half hour making molecules.
When daddy gets home from work today the kids can't wait to ask him if he would like a glass of "water"
(they think this is soooooo funny!)
Then they will hand him a glass full hydrogen atoms and oxygen atoms together making h20 molecules and (explain it to him) why that is a glass of "water." I'm sure he will be impressed. He better be!