Learning items

Explore shared ideas across books.

Physics

A quantum of the electromagnetic field.

In an ideal bound two-body Kepler orbit, the path is an ellipse with the attracting body at one focus in the usual relative-coordinate description.

A light-year is the distance light travels in a vacuum in one year.

Escaping molecules can remove energy from a liquid.

Matter's large-scale behavior can be explained through particles and their interactions.

Elementary particles that do not experience the strong interaction.

All items includes definitions still awaiting topic classification.