TOPIC:

ID Code: P1-11
Purpose: Models the effect of space curvature
Description: A ruled rubber sheet is stretched uniformly over a hoop, with a heavy weight placed in the center of the membrane. The lines indicate the curvature of space. Two smaller balls roll around the membrane to demonstrate the effect of curved space on moving bodies and light rays.
Availability: Available

This classic analogy for general relativity is actually rather misleading. For bodies moving much slower than the speed of light, the spatial curvature around a mass plays a negligible role in the orbital motion. Instead, the spacetime curvature in the time-radius manifold is what matters. For something moving at the speed of light, however, the spatial curvature is equally important.