Across
1
Gas form of a liquid
3
Second lightest element
6
Ball of burning gas in space
7
Reddish electrical conductor
8
Element found in all living things
11
Icy body with a tail near the sun
Down
2
Our home planet
4
Positive particle in nucleus
5
Naturally occurring inorganic solid
9
The Red Planet
10
Nerve cell in the brain
12
Unit of electric potential
13
Molten rock beneath Earth surface