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Why do we slip? |
We may slip when we try to ice skate. We might slip on a wet tile floor. We may even slip on a banana peel! But that’s not very likely.
What causes the slip in all these cases is a missing force called friction. Friction happens when two objects rub together but it doesn’t go smoothly. The two objects could be anything. Think about your shoes and the street. Your shoes have a rough bottom to them. The street will have a bumpy or rough texture too! When those two surfaces meet, the rough textures press up against each other, and it’s very difficult for them to slide past each other.
Sometimes though, a surface might be very smooth, like ice. Ice tends to have a little bit of melted water on its surface, which fills in all of the rough parts. When your shoe lands on ice, it doesn’t have a rough spot to grab onto, so instead, it wants to slide! There is a lot less friction. That’s why, a lot of times, cities put sand on snowy and icy streets, so they stay rough and car tires don’t want to slide as easily.
Friction at Hand
If you rub your hands together really quickly, what do you feel? The friction that comes from your hands rubbing together actually gives off heat!
Now try it again, but this time put some soap and water on your hands. Is there heat this time? Do your hands rub together more smoothly? What is the soap and water doing to the rough spots on your hands that were causing friction before?
Grown-ups like this experiment because you learn AND wash your hands!
