Learning about gravity

What makes a feather fall to the ground if you drop it?

GRAVITY!

Gravity pulls everything to the ground.

We tried to answer a few questions:

Will gravity pull a feather or a piece of paper to the ground faster?

(It looks like it pulls the feather faster but maybe that is just that the paper gets caught on air currents)

Which will fall faster, a flat piece of paper or a feather?  Watch closely for the answer:

Which will fall faster, a piece of flat paper or a piece of crumpled paper?

(It depends on how you hold the flat paper, in our test they fell together, but sometimes the air currents catch the flat paper causing it to slow down).

Will a full bottle of water fall faster than an empty bottle of water?

(No, they will fall at exactly the same time because although the force of gravity is stronger on the heavier object, the heavier object is more inert and will take a greater force to get it moving.

  This is why both objects of unequal weight will fall at exactly the same time.)

Which will fall faster, a hammer or a feather?

(The hammer, because it doesn't float on the air)

If you tried this on the moon what would happen?

(Have a look at this ACTUAL experiment on the moon!)

Here's a version done in a vacuum chamber: