Acceleration

Acceleration is all about change in motion. If a car starts going faster, it is accelerating. If it slows down, that is also acceleration. Even turning counts as acceleration. Scientists measure it to understand how things move.

Speeding Up and Slowing Down

When you push a bike pedal harder, your bike accelerates. You go faster and faster. When you press the brakes, you accelerate in a slowing way. This is sometimes called deceleration. Both are types of acceleration in science.

Gravity and Falling

Gravity makes things accelerate toward the ground. A dropped ball falls faster and faster. On Earth, every falling thing speeds up about 22 miles per hour each second. The Moon has less gravity, so things fall more slowly there. Astronauts can even do slow-motion jumps on the Moon.

Fun Facts

• Roller coasters are fun because of fast acceleration.
• A cheetah can accelerate from 0 to 60 mph in just 3 seconds.
• Rockets need huge acceleration to leave Earth's gravity.

Did You Know?

Astronauts feel pushed into their seats during liftoff because the rocket is accelerating so quickly.