Across
1
Reddish electrical conductor
5
Natural satellite of Earth
7
Solid with repeating atomic pattern
8
Naturally occurring inorganic solid
13
Mass per unit volume
Down
2
Ball of burning gas in space
3
Gas essential for breathing
4
Positive particle in nucleus
6
Push or pull on an object
9
Amplified beam of light
10
Unit of energy
11
Disturbance that transfers energy
12
Substance with pH below 7