All tripods have a couple parts in common, including the legs and the head. Typically, tripod legs are expandable—so you can set the sticks to any height you want.

The tripod "head" is the part that attaches to the camera.

Fluid Head

Good tripods have a "fluid" head which has two chambers of goo. Panning or tilting pushes the goo from one chamber to the next. Why create goo chambers? Because the goo offers resistance. It dampens jerky moves, resulting in smooth, professional camera movement. One way to understand how this works is to imagine running in three feet of water. All moves are dampened, slowed down, and "smoothed out." That's a pretty good analogy to how fluid heads work.