| A | B |
| the amount of mass in a given amount of space | density |
| energy that can travel through air and space | radiant energy |
| a lens that can curve light outward | concave lens |
| how much space a substance takes up | volume |
| the bending of light as it passes from one material to another | refraction |
| an object that blocks light as it passes through it | opaque |
| when light that hits an object is taken in by the object | absorption |
| an object that allows light to pass through it | transparent |
| the way that light hits a surface and bounces off | reflection |
| a lens that can curve light inward | convex lens |
| an object that allows light to pass through it, but scatters it | translucent |
| anything that has mass and takes up space | matter |
| measures the amount of gravity between an object and a planet | weight |
| the amount of matter making up an object | mass |