Across
1
Measure of matter in an object
3
Path of a planet around the sun
5
Form of thermal energy
6
Particle of light
9
Push or pull on an object
11
Compound containing oxygen
Down
2
Amplified beam of light
3
Gas essential for breathing
4
Group of similar cells
7
Natural satellite of Earth
8
Smallest unit of an element
10
Unit of energy