Forces and Motions

In my science class we are stating a new unit on forces and motions. I already know a few things about them. They  are kinetic and potential energy.  Kinetic energy would be if you put a ball on a hill and it was rolling down because it has and is using energy. Potential energy is when a ball is at the top of a hill next to the slant so it has energy but it is not using it because it is not moving. I also know that gravity is what can make us float of stay down. In space there is low gravity so we float, on Earth we a quite a bit of gravity but not to much because then we would be scrunched down.  Another thing I learned was that heavy things fall down quicker than light things. I want to learn more about positive and negative energy, how when you spin a bucket of water nothing comes out. I want to learn these by doing some tests, for example, dropping multiple things with multiple weights off a even height.