📣 Sound – main characteristics
🔈 Sound – main characteristics
What is the sound?
Do you know that sound is a vibration?
🔍 Observe
Play music at home and put your hand on the speaker. Did you feel the vibration from the speaker? Now put your hand on your throat and try to hum with your mouth shut. You felt the vibration in your hand again, didn’t you?
When we speak, sing, or hum, it causes a vibration that comes out of our vocal cords and hits neighboring air molecules, causing the air to vibrate.
🤔 Can you remember?
Now try to remember the summer thunderstorms. What have you been noticed during a strong thunderstorm? Did you remember how the windows at home vibrated after every nearby thunder? Can you guess why?
Yes, correct! When there is a thunderstorm, a loud sound is heard, caused by each thunder. This loud sound causes the air molecules to vibrate, and these vibrations are transmitted through the individual air molecules and reach the windows, causing them to ring (tremble). The sound travel in the form of waves, similar to those generated on the lake surface, when you throw a pebble into the lake.
Have you ever thrown pebbles in a lake or a dam in the summer? Yes? Have you noticed what happen?
Yes, correct! Every time, when the pebble hit the lake surface small circle waves are generated. These generated waves increase their width and distance from each other, gradually attenuating as they move away from the place where the pebble (stone) hit the water. The further away from the center (the place where the pebble falls into the water), the greater is the distance between these waves and the weaker they become.
This is very similar to the way sound waves travel.
Every sound we hear is an invisible (for our eyes) vibration that travels through the air, hitting air molecules.
You already know that when you speak, your vocal cords vibrate. They are the source of the sound of your voice. The vibrations they created cause air molecules to vibrate as they transmit these vibrations to each other. This moving vibration is the sound wave.
How do we hear a sound?
When the sound wave (generated by the sound we hear) reaches our ear, it makes our eardrum to vibrate and so we hear the sound. The closer the sound source is to us, the clearer and louder the sound we hear will be. The farther away we are from the sound we hear, the louder and fainter we will hear it.
The voices of different people, as well as the sounds we hear every day, sound different. Each sound generates a specific sound wave that creates a different oscillation of the air molecules and our eardrum. This is how we hear and distinguish different sounds.
