Across
1
Nerve cell in the brain
4
Naturally occurring inorganic solid
8
Second lightest element
9
Gas form of a liquid
10
Compound containing oxygen
11
Amplified beam of light
14
Hottest planet in solar system
Down
2
Element found in all living things
3
Unit of force
5
Icy body with a tail near the sun
6
Positive particle in nucleus
7
Our home planet
12
Natural satellite of Earth
13
Mass per unit volume