Seeing if Earth is Flat

Is there an experiment you can do at home to prove the earth isn't flat?
- (anonymous) (age 13)
NJ

There are several things you could do. These include looking up at the sky during a lunar eclipse to see that the Earth's shadow is round. Of course, that doesn't rule out the possibility that tthe Earth could be a flat disk, but then it's hard to explain how the shadow could look circular on every lunar eclipse even as the part of the Earth facing the Moon varied.

If you live near water you could see how the distance out that you can see things on the surface varies depending on how high your viewing point is. With a little geometry, you can then show how much the surface of the water curves and use that to measure the Earth's diameter.

Mike W.

(published on 04/26/2018)