Book 3, Question 11 · Video
Why Do Tires Have Treads?
Rain makes a thin film of water on the road. Tread grooves cut paths, so the water can shoot out. Then the rubber can grip the road instead of surfing on the water!
Read the full answer →What Crafty Clover says in this video
Intro
Hey there, curious minds! I'm Crafty Clover! Let's discover something amazing. Why do tires have treads?
The Big Idea
Rain makes a thin film of water on the road. Tread grooves cut paths, so the water can shoot out. Then the rubber can grip the road instead of surfing on the water! It works like tiny rain gutters, all around the tire.
Step 1
Step one: rain on the road. When it rains, a thin film of water covers the pavement. That water can make it slippery for a tire. A tire without grooves is called bald, and bald tires can skid.
Step 2
Step two: grooves cut paths. The grooves in the tread give the water a place to go. As the tire rolls, the water shoots out through those little channels. Bike tires and sneaker soles use the same groove idea.
Step 3
Step three: the rubber grips the road. With the water gone, the rubber touches the road and grips it. A bald tire has no escape channels, so water stays under it, and the car can slide. Tractor tires have deep lugs for mud.
A Closer Look
Let's take a closer look at a tire! The rubber outside grips the road. The grooves are the channels for water. And steel belts inside make the tire strong. Grooves, grip, and go! Every layer of the tire has an important job.
Quick Facts
Quick facts! Tread depth is measured in tiny units, so mechanics can tell when a tire is worn. Worn tires fail in the rain first. Winter tires have extra tiny slits, called siping, for snow. Race slicks have almost no tread, because racetracks stay dry. Mechanics check tires often to keep drivers safe.
Think Like a Scientist
Now, think like a scientist! First, wipe a wet plate with the bottom of a cup. Then wipe the same wet plate with a fork. The fork leaves channels, just like tire tread. Which one clears water better, and why? Try to picture how the water squeezes out.
Outro
Tread grooves send water away, so tires can grip. Great job, explorers! Crafty Clover can be found on Amazon Books, Google Bookstore, and Apple Books. Available for purchase or download! Bye for now!