The great blocks of stone that made the pyramids weren't lifted into place they were rolled up ramps, or what we now call inclined planes. The inclined plane, one of the simple machines, allows you to raise great weights with small forces. This model lets students experiment with this principle directly, by seeing how much force is needed to pull the cart up the ramp. This classic wooden model offers children a basic concept of the laws of physics. Desktop sized. Recommended age 9+ years