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We already know that sound is made of sound waves, vibrations traveling through the air to your ears. But can these sound waves travel through something other than air to your ears? How about a solid object? Let’s find out!
Materials
- A wire coat hanger
- Some string, yarn, or twine
- Scissors
- Something to use as a drumstick—a fork, a spoon, a pencil, an actual drumstick, etc.
Process
- Cut two pieces of your string, yarn, or twine about 1-1½ feet long.
- Tie your pieces of string to the corners of the wire hanger.
- Wrap the other ends of the string around the very ends of your index fingers a few times. Make sure it’s not so tight that it hurts or cuts of the bloodflow to your fingertips!
- Have a grown-up tap the long bottom part of the hanger with your makeshift drumstick while you hold it up. What does it sound like?
- Now stick your index fingers in your ears and have the grown-up tap the hanger again.
Summary
What did it sound like with your fingers in your ears?
The sound that you heard was something only you could hear! Anyone standing close to you would have heard the same sound you heard the first time the hanger got tapped. That sound was the hanger sending sound waves through the air to everyone’s ears. When you wrap your fingers with the string and stick them in your ears, though, the sound waves vibrate the string, which sends those vibrations into your fingers and then directly into your ears! Sound actually travels through solid objects more easily than through air because the molecules, the tiny particles that make up everything, are closer together in a solid object.
Sound can travel through liquid, too. Try this out next time you take a bath: tap a fork on the side of the tub under the water. What does it sound like? Now stick your head under the water and tap the fork again? Is it different when you’re under the water, too?
As long as there are molecules to vibrate, sound can travel. This is why sound can’t travel through space: empty space has no matter in it, so no molecules to vibrate!
Want more Saturday Science? See all of our at-home activities on the blog or on Pinterest.
