How is Sound Produced?

An object makes sounds by vibrating back and forth.

Parts of the vibrations of sound

When sound is produced, the vibrations create ranges of air with many particles. These are called compressions.

The vibrations also form ranges of air with fewer particles. These are called rarefactions.

The compressions and rarefactions move through the air carrying sound energy

What is a Sound Wave?

A sound wave is a series of compressions and rarefactions. The medium of a sound wave is the object that the wave passes through. The medium is not permanently moved when a sound wave passes through it.

Sound waves include peaks and dips. Peaks represent the compressions, and the dips represent the rarefactions.

How does Sound Travel?

Sound travels through solids, liquids, and gasses. It tends to travel faster in solids than in liquids or gasses. It travels slowest in gasses. This is because sound energy travels through the collisions of particles. Since the particles in solids are closer together, sound travels fastest through solids.

Sound travels faster in warm air because the particles collide more often.

What is Absorption?

Absorption is when sound waves disappears and gets converted into kinetic and thermal energy. Absorption is often used in sound-proof rooms.

What is an Echo?

An echo is when sound waves hit a flat surface, and most of it’s energy bounces off the surface. Echoes are not as loud as the original sound wave because some of the energy is absorbed into the surface.

What Effects Sound Waves?

• Frequency
  • This is the number of times an object vibrates per second.
  • The more the object vibrates, the higher the sound will be.
  • Higher Frequency sounds have peaks closer together.
• Pitch
  • Pitch is how high or low a sound is.
  • It is related to frequency.
• Volume
  • The amplitude is how dense the air is between the compressions and rarefactions.
  • Volume depends on amplitude of the sound waves
  • Louder objects produce longer sound waves

What is Echolocation?

Bats make sounds that bounce off of their prey. This way they find their food. This process is called echolocation. It is also used by whales and dolphins, who use it to locate their prey exactly like bats.