What happens to radio waves, time, and light in and near a black hole? Young scientists explore what is known about observing frequency and time at various distances from a black hole. They control the size of the black hole and the...

This model permits manipulation of variables in order to observe the effects of time dilation on twin objects, one moving and one not, as shown in a spacetime diagram.

This site, in German, offers numerous apps that illustrate common physics principles. Apps are organized into categories: mechanics, oscillations and waves, electrodynamics, optics, thermodynamics, the theory of relativity, physics of...