Across
1
Unit of energy
2
Unit of power
4
Group of similar cells
6
Icy body with a tail near the sun
7
Naturally occurring inorganic solid
9
Substance with pH above 7
10
Particle of light
12
Chemical element in table salt
Down
2
Disturbance that transfers energy
3
Tissue that contracts for movement
5
Second lightest element
8
Unit of force
11
Magnetic metallic element
13
Smallest unit of an element