A sample section (minus the graphic graphics) from this fun nonfiction that explains the physics and biology behind size:
I'm sorry if you are disappointed to hear that you will never be able to fly, sprint up windows, dance on ponds, or be stronger than an ant. But since you can't be a superhero, the BTLT rule will do your monster-busting for you. Let me show you how. Let's start with a Terrible Tale of Giants. . . .
Once upon a time there was a giant who was just like a normal human, only ten times bigger all over. Ten times taller, wider, and deeper, making him one thousand times heavier. The giant took his first giant step, and with a giant crashing sound, both his legs snapped. The end. (And exactly the same thing happened to the giant's best friend, the monster spider!)
Remember, strength doesn't keep up with weight, because strength depends on the size of the cross section. In this case, the cross section, or slice, through the giant's leg is a hundred times bigger than a normal human's, so only a hundred times stronger--much too weak to take the giant's huge weight, a thousand times greater than a normal human's!
A real 60-foot-tall giant would need legs that were so thick they would probably be too heavy to lift.