Across
1
Icy body with a tail near the sun
4
Unit of energy
5
Naturally occurring inorganic solid
7
Substance with pH below 7
10
Unit of power
11
Curved glass that refracts light
Down
2
Chemical element in table salt
3
Amplified beam of light
6
Tectonic landmass section
8
Preserved remains of ancient life
9
Our home planet
12
Substance with pH above 7