Conversation so far:
what is earth's motion around the sun in a path called
The Earth orbits, or revolves around the Sun. This movement is called revolution.
who used a pendulum to test earth's rotation
Léon Foucault was a French physicist best known for his demonstration of the Foucault pendulum, a device demonstrating the effect of the Earth's rotation.
how long does it take earth to make one rotation
Earth rotates once in about 24 hours with respect to the Sun, but once every 23 hours, 56 minutes, and 4 seconds with respect to other, distant, stars

Question: what is the axial tilt
Self-contained rewrite: what is the axial tilt of earth