When you listen to your favorite singer or your favorite rock group, this is only possible because you are inside Earth’s atmosphere.Sound can’t travel in space due to the vacuum that exists there.

But lets start from the beginning, ok?

What is “sound”?

Sound is a vibration in the air. Anything that can produce vibrations can produce sound. Humans can listen to a wide range of sounds but there are sounds we can’t listen to. There are the so-called “infra-sound” that are so low in pitch that we can’t notice them. On the other edge there are the “ultra-sounds” that are so high that only dogs cats and some other animals can listen to them.

When we say “low” and “high” we are talking about frequency not volume. A low frequency is like the sounds of a Bass (in Portuguese “contrabaixo”) . A high sound is like the sound of a piccolo, a very small flute with a very acute sound.

Remembering the Physics from High School, the sound speed is about 340m/s, that is, in a second a sound can travel 340 meters in open air. Sound can travel in the water much faster than in the air. If you’ve already seen a movie about submarines you‘ve probably heard the “pings” of sonar equipment. The submarine sends a beep under the water and receives an echo from any obstacle even fish. The equipment measures the time of return and gives a reading about the distance of the obstacle. Very practical, isn’t it?

But all this sound applications have no special meaning in our daily lives, right?

Sound can be a blessing when we listen to our favorite song, or a very uncomfortable thing when we are on the streets.
 

The noise of heavy traffic is very dangerous and irritating to our ears, not to mention our stress level. People who work in noisy places are more likely to have health problems like deafness, stress, headaches and even heart attacks. Workers must wear ear protectors when working on the streets or noisy factories. There are Laws about that to protect people’s health.

Our civilization is really noisy with all the engines, sound equipment, TV, Public Address loudspeakers and hundreds of other sound sources.

Sound is the basis of oral communication, and that was the original use of it.

Pay attention to the hundreds of sounds you listen every day. You’ll notice that about 90% of them are useless.

If the sound level is too high it will damage your hearing. People who are exposed to high sound levels for more than one hour a day will have hearing loss in near future. Protect yours ears and your health.

 Enjoy the good 10 %, and when you get home close the windows, low down the TV sound, turn off the radio and enjoy the silence.
It’s wonderful!