Sound—it’s almost impossible to imagine a world without it. When people talk to us, when we listen to music, or when we hear interesting programs on the radio and TV. The sound may be the last thing you hear at night as well when you listen to your heartbeat and drift gradually into the soundless world of sleep. Sound is fascinating—let’s take a closer look at how it works!
What is Sound?
Sound is the energy things produce when they vibrate (move back and forth quickly). If you bang a drum, you make the tight skin vibrate at very high speed (it’s so fast that you can’t usually see it), forcing the air all around it to vibrate as well.
As the air moves, it carries energy out from the drum in all directions. Eventually, even the air inside your ears starts vibrating—and that’s when you begin to perceive the vibrating drum as a sound.
Medium to travel sound:
Sound travels at different speeds in different gases—and can go at different speeds even in the same gas. It travels much faster in warm air near the ground than in colder air higher up, for example. And it travels roughly three times faster in helium gas than in ordinary air, because helium is much less dense. That’s why people who breathe in helium talk in funny voices: the sound waves their voices make travel faster—with higher frequency.
However, it does not travel at all in a vacuum, because the sound waves need some kind of medium in which to travel. In addition, some materials absorb, rather than reflect or pass, sound waves. This is the basis of soundproofing.
The average speed of sound through air is about 1130 feet per second (344 meters per second) at room temperature. However, changes in temperature and humidity will affect this speed.
How to Measure the Speed of sound:
Here is a simple way to measure the speed at which sound travels through the air.
You’ll need the following items:
- Two blocks of wood, or other items that make a loud, sharp sound when struck together
- A stopwatch
- A friend to help with the experiment
- A tape measure
- Find a large empty area, such as a field or large court.
- Choose two spots on opposite ends of the area where each person will stand.
- Measure the distance between the two spots using a tape measure. Alternatively, you can count off measured steps between the two spots.
- Have your friend take the blocks and stand at one spot, holding them up high.
- Take the stopwatch and stand at the other spot. Make sure you have a clear view of the blocks.
- Signal your friend to bang the two blocks together hard.
- Start the stopwatch as soon as you see the blocks hit each other.
- Press stop as soon as you hear the sound from the blocks.
- Calculate the speed of the sound by dividing the distance between you and your friend by the elapsed time.
- To get a more accurate measurement, repeat the above steps a few times and then take an average of the results.
Sound is a hugely important part of life on Earth. Most animals listen out for noises—things that signal the possibility of eating or being eaten. Many creatures also exchange meaningful sounds, either to communicate with members of the same species or warn off predators and rivals. Humans have evolved this ability into the spoken language (as a way of exchanging information) and music.
We’ve also developed a variety of different sound technologies. We’ve invented musical instruments that can make a huge range of different musical sounds, from simple drums and percussion instruments to sophisticated electronic synthesizers that can generate any sound you care to imagine.
Get Free “Winspire Digital Worksheets of worth Rs. 129 Value”
Please enter your details to get the monthly E - Booklet + absolutely premium content to expand your horizons.