Marvin and Milo
Explore physics the exciting way, by trying out a simple and fun experiment. This month, Deceptive CD Don't forget to check back next month for the next edition...
What you need
A small glass bottle
An effervescent indigestion tablet
- Pour about 2cm of water into the bottle. Blow across the top of the bottle and listen carefully to the sound it makes.
- Break the tablet in two, and put both halves into the bottle. Wash your hands while you wait for it to stop fizzing.
- Blow across the top of the bottle again and listen to the sound it makes now.
Results & explanation
Sound travels more slowly through carbon dioxide (the gas given off by the fizzing tablet) than through air, so when you blow across the bottle you hear a lower pitched note.
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