Book 3, Question 8 · Video
Why Do Cars Need Brakes?
A moving car has lots of energy. Brakes squeeze a spinning disc, and the rubbing makes heat. That turns the car's speed into warmth, and the car slows down.
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 cars need brakes?
The Big Idea
A moving car has lots of energy. Brakes squeeze a spinning disc, and the rubbing makes heat. That turns the car's speed into warmth, and the car slows down. Brakes are speed-to-heat machines! That is why a car can stop, even when it is going fast.
Step 1
Step one: press the pedal, and the pads squeeze. When your foot presses the brake pedal, fluid pushes brake pads onto a spinning disc. It works like squeezing the brakes on a bike, only much stronger.
Step 2
Step two: rubbing makes heat. The pads rub against the disc, and that rubbing is called friction. Friction is the real stopper, because it turns motion energy into heat. Bikes, trains, and planes all use friction to dump speed.
Step 3
Step three: the wheels slow down, and the car stops. As the disc slows, the wheel slows with it, and so does the whole car. This is why cars need brakes, and why good brakes keep everybody safe.
A Closer Look
Let's take a closer look at the brakes! The brake disc spins along with the wheel. The brake pads squeeze the disc from both sides. And all that rubbing makes heat. Squeeze, rub, slow down! A long downhill can make brakes so hot that you can smell them.
Quick Facts
Quick facts! Disc brakes throw heat out into the air, so they don't get too hot. You can feel friction yourself. Rub your hands together fast, and they get warm. Worn brake pads must be replaced, so the brakes keep working. Many cars have ABS. It pumps the brakes so the wheels do not lock up.
Think Like a Scientist
Now, think like a scientist! Try a friction test. First, rub your hands together fast. Next, feel how warm they get. That warmth is friction, the same thing that helps brakes stop a car. And keep a grown-up nearby for any car or bike brake test.
Outro
Brakes turn speed into heat, and friction does the work. Now you know how cars stop! Crafty Clover can be found on Amazon Books, Google Bookstore, and Apple Books. Available for purchase or download! Bye for now!