How to prove that the earth revolves?

Question

As a kid, when I learned that the earth moves all the time, I used to hop to find out whether I would land at a different spot. The experiment failed every time, and humanity lost another Galileo. The question is: how high should one jump to land on a different spot, and thereby prove that the earth revolves?

Answer 1

wouldn't it be easier to prove/demonstrate that the world rotates by observing the behavior of a very large pendulum?


if you go with the jumping experiment approach, you have all sorts of conflicting variables.

Answer 2

Your horizontal momentum (since you are moving along with the earth) is what causes you to land on the same spot. In order to land on a different spot your body would have to be slowed down relative to the movement of the earth by an external force. Imagine you are in a train. If you jump, since the train is moving, do you land on a different spot? To prove that the earth revolves, simply take a camera out at night and photograph the stars every 15 minutes as long as you have darkness. Make sure you take pictures from the same position and angle. Next, print out the pictures so you can make a "flip book" to animate your pictures. You will see that the stars in the sky are moving relative to the ground thus proving that the earth revolves.

Answer 3

The only way to observe the effect you are talking about is with a pendulum. A big one.

Start a very large pendulum swinging and it will maintain a path in relation to the place where it started. As the earth rotates, the path of the pendulum remains the same (momentum) yet the room around it shifts slightly.

At observatories (like Griffith Park in LA) you can observe this amazing phenomena as the pendulum knocks over little pegs on schedule as the earth rotates.

This is how Galieo proved the rotation of the earth - by observing lamps in a tall cathedral making the same motions.

Answer 4

You can't do it that way. You begin with the earth's motion, and the act of jumping (straight up) does not alter this fact. In other words, the earth won't be rotating under you, but you and the earth will rotate together.

There are any number of other methods to show the earth's rotation. Foucault's pendulum was probably the first direct physical evidence, other than astronomical observations. But astronomical observations are still among the best; a Greek named Aristarchus got it right more than 2000 years ago.

Answer 5

Foucault's Pendulum the original and most positive proof of a rotating planet. the reason that jumping up and own fails is that there is no motion along the surface if you could site about a mile away and then jump directly at it it might give enough time for the earth to move and your target to move out of your way before you got there.

Answer 6

Very interesting that you tried to find proof yourself. For me you are kind of Galileo. The movement around its own axis is to rotate. One rotation takes 24 hours. It causes day night day night ... . You can prove this movement with a very long and heavy pendulum. Read about Foucault.

The earth's movement around the sun is to revolve. One revolution takes 1 year. It causes summer winter summer winter .... The proof is seen that all the star constellations shift. That is why the summer night sky looks different from winter night sky.

Answer 7

Here's the easiest proof - the sun rises in the east, at noon its overhead, and it sets in the west!

Jumping won't do a thing for you, because you are already travelling at the earth's rotational velocity - so when you jump your inertia makes you land back on the same spot.

Answer 8

If you could truly jump straight you would have to jump high enough to leave the gravity of earth then come back down. Otherwise inertia will take you with the earth.

Answer 9

You can't hop high enough! It would be necessary to hop completely out of the atmosphere and hang suspended long enough for you to bleed off the roughly 1,000 mph of velocity we all gain from Earth's rotational speed.

Answer 10

The proof is in the sky. Just look up the night sky and watch the stars. They are rotating because earth is rotating.