Solids, Liquids, and Gases: Matter

The video explains that all things, living or non-living, are composed of matter, including invisible elements like air. Matter is defined as anything that has mass and occupies space. It is made up of tiny particles, and the movement and spacing of these particles determine whether matter exists as a solid, liquid, or gas.

Can you name something that is made up of matter but is not visible?

What are the small particles that make up matter?