Across
1
Nerve cell in the brain
5
Group of similar cells
6
Disturbance that transfers energy
7
Smallest unit of an element
8
Fourth state of matter
11
Unit of energy
13
Form of thermal energy
Down
2
Glass that splits light into spectrum
3
Absolute temperature scale unit
4
Curved glass that refracts light
9
Substance with pH above 7
10
Biological catalyst
12
Mass per unit volume