Chapter 12 page 298
You know that water feels wet and soft. You might think that each molecule is wet and
soft, too. But that is not true. Each molecule of water acts as if it was quite hard and dry.
Molecules bump into each other and slide past each other as if they were very hard.
Why does water feel wet and soft when each molecule is hard and dry? The answer is
that the water molecules are so very very small. When you touch water, you are touching
billions and billions of molecules all at the same time. All of these billions of molecules
together feel wet and soft. But if you could become incredibly small, almost as small as a
water molecule, you would see that each individual molecule is hard and dry.
Think about a bowl of bird seed. Bird seeds are very very small. You can stir a bowl of
birdseed and pour it. You can easily move your finger around in the bowl of seeds, and all the
seeds together feel smooth and soft as you move your finger. Each seed by itself is hard. If
you touch one seed by itself, it feels hard. But thousands of seeds together feel very different.
When you stir water with your finger, it is the same thing. You are feeling billions of molecules
at the same time. All together, they feel soft and wet and smooth. Each one alone, though,
would feel hard, if you were small enough to feel it.