A very busy day today so I thought I’d just do a quick post to give you a chance to test your brains with some more order-of-magnitude physics problems. I like using these in classes because they get people thinking about the physics behind problems without getting too bogged down in or turned off by complicated mathematics. If there’s any information missing that you need to solve the problem, make an *order-of-magnitude* estimate!

Give order of magnitude answers to the following questions:

- What is the tension in a violin string?
- By how much would the temperature of the Earth increase if all its rotational energy were converted to heat
*?* - What fraction of the Earth’s water is in its atmosphere?
- How much brighter is sunlight than moonlight?
- What is the mass of water in a soap bubble?

There’s no prize involved, but feel free to post answers through the comments box. It would be helpful if you explained a bit about how you arrived at your answer!

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