Grades K–2 · Machines
How does a little bell keep ringing after a strike?
A little bell has a metal shell and a moving piece inside called a clapper. When the bell is moved, the clapper can strike the shell.
In the diagramA strike starts a bell ringingThe metal shell shakes the airShellClapperThe clapper has struckA freely shaking shell can keep ringing after a strike.
The strike makes the shell shake very quickly. The shaking shell moves the air around it. That changing air pressure travels outward as sound. The bell can keep shaking after the clapper has moved away.
The ringing slowly fades as energy spreads to the air and other surroundings. Touching the shell slows its shaking and makes the sound fade faster. The shell makes the ringing; the clapper starts it.
About this explanation
Starting knowledge: Notice that shaking can make sound.
Sources
- Malmark — Handbell restraining springs
- OpenStax — Sound