Sound Wave
Light, Sound and Waves

A noisy alarm clock

Classroom Activity for 5-11 Supporting Physics Teaching

What the Activity is for

Help with fixing noisy and quiet devices.

Children think about the path which the vibrations must follow from source to detector in order for this sound to be heard. To make this goal orientated, and to allow for little lateral thinking, we suggest sketching two scenarios in which the path is able to transmit more of vibrations from the source and in which the path is able to translate less of the vibrations from the source.

What to Prepare

  • A noisy, mechanical alarm clock: the more obvious and bell-like the ringer, the better

What Happens During this Activity

Set up a situation as a puzzle to be worked on in one of these two possible ways:

Teacher: My granny bought me an alarm clock. It’'s great and I like it very much – it wakes the whole house up as well as me and my teddy. How can I make it quieter without upsetting my granny by damaging the alarm clock?


Teacher: I bought my teddy an alarm clock, but my teddy sleeps very heavily and he doesn't wake up properly. How can we make the alarm clock louder to help him?

It is perhaps best to set this up as an open-ended activity, Giving pointers or hints as necessary. It's very likely that you'd managed to think of other examples of every day activities which can be substituted for these two.

2021 IOP Awards

Teachers of Physics Award

Recognising and celebrating outstanding contributions to the field of physics education.

Learn more