How Sound Travels

Sound is made when something vibrates. The vibrations push air molecules back and forth, creating waves. These sound waves travel through the air to your ears. Sound can also travel through water and solid objects. In fact, sound travels faster through water and solids than through air.

Sound Waves

When a guitar string vibrates, it pushes the air molecules next to it. Those molecules bump into the next ones, and so on. This creates a wave of compression that travels through the air. The wave reaches your ear and makes your eardrum vibrate. Your brain interprets these vibrations as sound.

Speed of Sound

Sound travels at about 767 miles per hour through air at sea level. It travels about four times faster in water and even faster through steel. Sound cannot travel through a vacuum like outer space because there are no molecules to vibrate. That is why there is no sound in space.

Fun Facts

• Sound travels about 4,900 feet per second in water, compared to about 1,125 feet per second in air.
• The sound barrier is broken when an aircraft flies faster than the speed of sound, creating a sonic boom.
• Whales can communicate over hundreds of miles because sound travels so well through water.

Did You Know?

You can tell how far away lightning is by counting the seconds between the flash and the thunder. Every five seconds equals about one mile. Light travels almost instantly, but sound takes about five seconds to travel a mile!