Sound is all around us, but most people don’t know much about it. Here are some fun facts about sound to get you started!
- Sound travels much slower than light, whether in the air or water. Light travels 186,000 miles per second, while sound travels 770 miles per hour. As a result, you often hear things after you see them – for example, you see the lightning before you hear the thunder!
- The sound of a baby’s cry is hard to ignore. It is because it alerts a particular part of the brain.
- The fear of noise is called Acousticophobia, and the fear of music is called Melophobia.
- We measure sounds humans can hear in ‘decibels’ (dB). Sounds above 85dB can be considered harmful to human ears. For example, Normal conversation is
- Sound waves need particles in the air because they bounce off the vibrations and can travel from one to the other. It is why there is no sound in space – there are no particles from which the sound can bounce!
- Sound volume (how loud a sound is) is measured in bels. Bels are named in honor of Alexander Graham Bell, known for inventing the telephone.
- One of our favorite facts about sound waves is that when they bounce off a surface, the vibrations are reflected, and you can hear them again; this creates an echo.
- Scientists use sound waves to measure the depth of the ocean. They use a machine called a SONAR (Sound Navigation and Ranging). It sends sound waves and waits to see how long it takes for the waves to return. Ships and submarines also use SONAR to navigate the ocean.
- Dogs can hear much higher sounds than humans, and bats and dolphins can hear sounds much lower than humans.
- The three smallest bones in our bodies are in the ear, and they help us to hear sounds! They are called the hammer, the anvil, and the stirrup. Together, they are about the size of a pea!
- Usually, animals with more prominent ears can hear much better than smaller ones – and flies cannot hear at all!
- The scientific study of sound is called acoustics.
- A tribe in Africa – called the Maabans – live in such quiet conditions that they can hear each other whispering across a baseball field!
- The eruption of Krakatoa in 1883 is believed to be the loudest sound in human history. It was heard across roughly 8% of the whole world!
- Some fighter jets can travel faster than the speed of sound, called breaking the sound barrier.
- The human ear can’t hear some sounds, but they still affect our bodies. Some horror films use these sounds as they cause people to shake and feel nervous!
- Dolphins can hear sounds underwater from up to 15 miles away.
- The three loudest cities in the world are Mumbai and Kolkata in India and Cairo in Egypt!
- Most cows produce more milk if they are given music to listen to. Scientific experiments have looked at how different types of music can also affect how much milk they produce.
- Sound can travel around four times faster in water than in air.
