_Sound.pdf

3rd Grade Sound What is sound? Sound is a type of energy made by vibrations. When any object vibrates, it causes movement in the air particles. These particles bump into the particles close to them, which makes them vibrate too causing them to bump into more air particles. This movement, called soun...

3rd Grade Sound What is sound? Sound is a type of energy made by vibrations. When any object vibrates, it causes movement in the air particles. These particles bump into the particles close to them, which makes them vibrate too causing them to bump into more air particles. This movement, called sound waves, keeps going until they run out of energy. If your ear is within range of the vibrations, you hear the sound. Production and Propagation of Sound Sound is created when something vibrates and sends waves of energy (vibration) into our ears. The vibrations travel through the air or another medium (solid, liquid or gas) to the ear. The stronger the vibrations, the louder the sound. Sounds are fainter the further you get from the sound source. Properties of Sound Volume Volume, or loudness, is related to the strength, intensity, pressure, or power of the sound. Bigger/ amplified vibrations result in bigger/louder sounds. Pitch Pitch is the quality of a sound (high or low) and depends on the speed of the vibrations. Different materials produce different pitches; if an object vibrates quickly we hear a high-pitched sound, and if an object vibrates slowly we hear a low-pitched sound. Echo An echo is a sound that is repeated because the sound waves are reflected. Sound waves can bounce off smooth, hard objects in the same way as a rubber ball bounces off the ground.