Twisting, pushing, pulling, stretching--these are all ways we can physically use force and see how it affects things. Of course, there are many other forces on Earth that we can't see! Readers explore both the forces they can see in action and those they can only see the effect of in this engaging book. Activities accompany essential science information about magnets, friction, and gravity, airing readers' comprehension of what they've read. Simple diagrams support the experiments and main content.