Across
1
Particle of light
4
Ball of burning gas in space
5
Curved glass that refracts light
6
Natural satellite of Earth
8
Naturally occurring inorganic solid
Down
1
Fourth state of matter
2
Force that attracts objects together
3
Mass per unit volume
7
Push or pull on an object
9
Icy body with a tail near the sun
10
Chemical element in table salt
11
Element found in all living things
12
Basic unit of life