車はなんで走るの
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If you drew a picture of a tire kicking the ground, what would it look like?
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Transcript
Inside a car, something pushes hard to make it move. How does that push get all the way down to the road?
A gas car's engine burns air and gasoline together in a quick, powerful blast. That blast pushes a piston, which turns the motion into a spinning force.
The spinning force travels through gears and a long rod all the way to the tires. That's why the tires spin too, turning to move the car.
The spinning tire pushes hard against the ground, kicking it backward. The ground pushes back forward against the tire, and that's what makes the car go.
The engine's power travels all the way to the tires, and the ground pushes the car forward. Electric cars use a motor to spin their tires too, so they go the same way.
For grown-ups: the science
It's because the tire kicks the ground backward, and the ground pushes the car forward.
In a gas car, gasoline and air mix and burn quickly inside the engine, and the expanding gas pushes a piston. The piston's back-and-forth motion becomes spinning motion at the crankshaft, then travels through the transmission and drive shaft to the tires. The spinning tire pushes backward against the road, and by friction the road pushes forward on the tire, moving the car ahead. Electric cars make their spinning force with a motor instead, but they still move forward the same way, through friction between tire and road.