Mary Allen
Sound is anything that can be heard with the ears. With our ears, we perceive different noises, speech, and music, but also unpleasant noises. Sound always emanates from a sound source. This can be the human voice, a loudspeaker, an orchestra, or even a passing car.
However, humans only hear sound in a certain range. Some animals can also hear other areas. Bats orient themselves with extremely high-pitched sounds that we humans can no longer hear. We call this range of sound ultrasound. Very deep sounds outside of our hearing range are called infrasound. With this, elephants can communicate over several kilometers, but we humans hear nothing.
There are different types of sound: A struck tuning fork produces a clear tone. Musical instruments can produce different sounds. Noises occur when machines are operated. An explosion makes a bang. The difference between these types of sounds can be shown with certain measuring devices.
What are sound waves?
When it comes to sound, one also speaks of sound waves, which are similar to the waves in water. With the strings of a guitar, you can see the waves in the vibration. You can’t see that in the air. The air is compressed and then expands again. She passes this wave on to the neighborhood. A pressure wave is created, which spreads in space. That’s the sound.
Sound propagates in any substance at a certain speed. This speed is the speed of sound. The speed of sound in the air is about 1236 kilometers per hour.