The Normal Force
The Sun Magazine
...Last Tuesday, when Della got in the car, she asked me if I knew about the normal force. I like it when she talks about things she’s learning. It lightens her up for a minute, and I can see the child she used to be. So I said no, because I always say no, but this time, I actually didn’t.
It’s a contact force, she told me. It only exists when things touch in a certain kind of way. Like a table and the stuff you put on top of it, or your body and the doorframe you lean against. When two things come into this kind of contact, they have to actually push against one another, to stay as separate things.
Like gravity? I asked, but No. Gravity pushes us down, she said. Normal force is the thing that pushes back.
Cool, I said, and she said, Right?