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How can headphones fight noise with more sound?

A steady engine hum can fade when noise cancellation switches on, while a nearby voice remains noticeable. The electronics and the physical ear covering do different jobs, and neither makes every sound disappear.

4–5 min

Questions you could explore

  • How can two sound waves reduce the pressure changes reaching an ear?
  • Why does cancellation work differently for different noises?

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Why metal can feel colder than wood

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Why metal can feel colder than wood

Physics5–7 minA metal handle and a wooden tabletop can share a room temperature yet feel quite different. The clue lies in the exchange of heat between your hand and the surface, which is not the same thing as measuring temperature.

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3–5 min

Why does water climb a paper towel?

Physics3–5 minDip the corner of a paper towel into water and the wet patch can travel upward. Water's attraction to the material, together with cohesion between water molecules, helps it move through small spaces against gravity.

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