Why is a soft tap quieter than a hard bang?

Tap the table with one fingertip, very softly. Tap, tap. Now picture a door slamming shut with a big bang. One sound is tiny, and one sound is loud.

Your fingertip hits the table, and the door hits its frame. So why is a soft tap quieter than a hard bang? Let's find out together.

When you hit something, it starts to vibrate, which means shaking back and forth very fast. The table shakes too, even though it looks still. Your hit is the push that starts the shaking.

How hard you hit decides how big the shakes are. A soft tap is a small push, so the table vibrates with tiny shakes. A slamming door gets a big push, so the door vibrates with big shakes.

Air is all around us, even though we cannot see it. The vibrating table pushes on the air right next to it. Each shake gives that air a little bump.

That air bumps the air beside it, and on and on. The bump travels along, like a ripple across a pond. Soon it reaches your ear.

Deep inside your ear, a thin skin feels each bump of air. It wiggles, and your ear tells your brain. That is how you hear a sound! So what do you think big shakes do to the air?

Big shakes give the air big bumps. Those big bumps push hard on your ear, and you hear a loud bang. Tiny shakes give the air tiny bumps, so you hear a quiet tap.

Our special word today is vibrate. A harder hit makes things vibrate with bigger shakes, and bigger air bumps sound louder.

Now let everything around you grow soft and quiet, and sleep well, little listener.