OK. Here's an experiment that you all can carry on in your households, with simple daily items. It wont take more than a few minutes. Will also be a good proof to those who wanted proofs.

First of all, we'll construct a very simple pendulum for the measurement:

Get some rope, and cut off a 20cm (7.87401575 inch) piece. Tie one end to **any** piece of mass. From your high school knowledge, remember that the oscillation period of a pendulum doesn't depend on the mass-it depends on the length of the rope-so we're safe.

Now, use a compass to find and face 45 degrees North-west (or alternatively you may use Google earth to find the direction wrt your location and turn that way).

Find a stopwatch to measure time. We will indirectly measure the total coriolis forces on the pendulum.

This part is a little tricky. Facing NW, stand up, and balance a hard-cover book (or a glass of water) on your head to preserve your upright standing. With the pendulum on your left hand and the stopwatch on your right, lift your arms 90 degrees to your sides.

Do the following things at the same time:

1-shake the pendulum a little bit to give it a go, so it should start swinging. Count the swings it makes.

2-Start the stopwatch

3-Start turning around yourself counter clockwise (Clockwise if you're on the southern hemisquare)

Once you successfully finish 10 complete turns and face NW again, stop the stopwatch and record the time and the number of swings. If it took more than 30 second, please repeat it faster to get better results.

Now, still facing NW, repeat the steps 1 to 3, only this time do it on your left foot only (right foot if you're on the southern hemisquare). You may remove the book, and drink the glass of water if you wish. Again, record the time and number of oscillations.

Finally, divide the number of seconds you recorded by the number of oscillations you recorded. You should get 2 numbers for the 2 experiments you made.

If the numbers are close to each other (like 1.7 and 1.8 or 2.1241 and 2.3124), that means that the earth is spherical, so that both experiments yield the same result.

If the numbers are far apart (like 4 and 16 or 7 and 98), that means the earth is flat. The ratio of these numbers actually give you the width-thickness ratio of the flat earth.

Please post your result on this thread and let everyone see the real shape of the earth.