Light Sound and Waves

Bottle Blowing

Enrichment Activity for 5-11 11-14

What you need

  • Two identical glass bottles
  • A friend


  1. Ask your friend to hold one bottle up to their ear
  2. Standing quite close to your friend, blow across the mouth of your bottle and in the direction of your friend, so that you make a clear note
  3. Your friend will hear a similar note in their bottle!

Results and Explanation

The two identical bottles vibrate at the same natural frequency. So when one vibrates and produces a note, this makes the other vibrate and produce a similar note.

appears in the relation v=fλ E=hf f=1/T (f_o)/(f_s)=(v+v_o)/(v-v_s)
is used in analyses relating to Progressive Wave
has the special case Resonant Frequency Natural Frequency
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