Waking Up Experiment: Hot Drinks
By Mark Steer
This is a great experiment to wake up to - not too much thinking to do and you get a mug of coffee at the end of it. If you tap a mug of hot drink with a spoon, the pitch of tapping noise will rise as the drink cools down. Don't let it cool too far though - that would be a waste.What to do
- Pour yourself a nice hot drink – it works best with instant coffee or powdered hot chocolate.
- Immediately put a teaspoon into your mug and start tapping away on the bottom of the mug. You should hear a dull ring.
- Listen to the sound of spoon on mug begin to rise as the drink cools.
- Be impressed with yourself for being so dedicated to the scientific cause.
What happenedWell, it’s all a bit funny to be honest. And it’s all to do with bubbles. When the hot water hits the coffee/hot chocolate granules, tiny bubbles form in the water. The bubbles makes it harder for sound to travel through the liquid and out towards your earholes. Since sound is slowed down, the noise of your tapping becomes lower in pitch. However, as the bubbles rise to the surface and pop, it becomes easier to for the sound to move – it speeds up and gets higher.
| It really does work - this was our recording from the office. |
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This experiment has been adapted from Mick O'Hare's excellent book How to Fossilise your Hamster see more at www.newscientist.com/hamster.
How about trying one of our other top tens:
This experiment has been adapted from Mick O'Hare's excellent book How to Fossilise your Hamster see more at www.newscientist.com/hamster.
How about trying one of our other top tens:
- Top Ten Crazy Xmas Gifts
- Top Ten Geek Holidays
- Top Ten Stupid Science Studies
- Top Ten Work-related Ills
- Top Ten Killer Vegetables
- Top Ten Weird Drinks
- Top Ten Grim Parasites
- Top Ten Things Science Hasn't Explained
Hub image: Adriana Poveda
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