Does stirring a cup of tea make it cool quicker?
Attention all tea drinkers! Save your energy and let that cuppa cool on its own.
Asked by: Adrian Sinclair, Wiltshire
Yes, but not enough to make it worth doing. A metal spoon in a cup of tea will act as a radiator, conducting heat to the air. If you stir it as well, you are bringing the hotter liquid from the centre of the cup to the edges, where it can cool faster.
But experiments have shown that stirring a cuppa continuously for 10 minutes will only drop the temperature by 2°C, compared with just leaving it to stand. The fastest way to cool your tea down is to add a bit more milk, or a splash of cold water.
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Luis trained as a zoologist, but now works as a science and technology educator. In his spare time he builds 3D-printed robots, in the hope that he will be spared when the revolution inevitably comes.
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