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How much does a cloud weigh, and why doesn't it fall on your head?

A fair-weather cloud looks almost weightless, yet its tiny water droplets can add up to hundreds of metric tons. Estimating that mass starts with a volume and an average amount of liquid water per cubic meter. The droplets fall very slowly relative to the air, so rising air can keep them suspended; rain requires them to grow into much larger drops.

3–5 min

Questions you could explore

  • How do you estimate the total mass of something you cannot put on a scale?
  • What changes inside a cloud when those tiny droplets finally become heavy enough to fall as rain?

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How much does a cloud weigh, and why doesn't it fall on your head? | Speech Topic | speaking.app