Sound Waves

Sound is a type of energy that moves through the air in waves. When something shakes or vibrates, it makes sound. These waves travel to our ears so we can hear. Our ears send signals to our brains. The brain tells us what the sound is.

How Sound Travels

Sound needs something to travel through, like air, water, or even solid walls. Sound cannot travel in outer space because there is no air. Fast vibrations make high sounds, like a whistle. Slow vibrations make low sounds, like a drum. Sound travels faster through water than through air.

Loud and Quiet

Loud sounds have big waves with lots of energy. Quiet sounds have small waves. Loudness is measured in units called decibels. A whisper is very quiet, but a jet plane is very loud. Very loud sounds can hurt your ears, so it is good to protect them.

Fun Facts

• Dogs can hear sounds that are too high for human ears.
• Bats use sound waves to find food in the dark.
• Thunder is the sound made by super hot lightning heating the air.

Did You Know?

Sound travels about one mile in five seconds, which is why you see lightning before you hear thunder.