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What does “less oxygen” at altitude mean?

At altitude, the oxygen fraction of ordinary air can remain roughly the same while air pressure falls. Oxygen’s partial pressure falls with it. Keeping fraction and pressure separate makes the phrase “less oxygen” more precise, without turning a simple gas calculation into a prediction of someone’s blood oxygen or safety.

5–7 min

Questions you could explore

  • How can a mixture keep the same proportion while exerting less pressure?

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Why metal can feel colder than wood

A 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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Why metal can feel colder than wood

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4–5 min

How can headphones fight noise with more sound?

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3–5 min

How can a ship made of steel float?

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