* Energy: While energy is often associated with matter, it exists independently. Scientists study various forms of energy like light, heat, sound, and electrical energy.

* Forces: Forces are interactions that can change the motion of objects. Gravity, electromagnetism, the strong and weak nuclear forces are all examples of forces studied by physicists.

* Fields: Fields, like magnetic and electric fields, are regions of space where forces can act on objects. Scientists study how these fields are generated and how they interact with matter.

* Information: While information is often encoded in matter (like the information in a book), it can also exist independently, such as in radio waves or computer signals. Scientists study how information is transmitted, processed, and stored.

* Spacetime: In Einstein's theory of general relativity, spacetime is a fundamental entity that is not matter but is affected by matter and energy. Scientists study the geometry and evolution of spacetime.

These are just a few examples of non-matter things that scientists study. There are many others, and the line between matter and non-matter can be blurred in some areas of physics.