Across
1
Nerve cell in the brain
4
Compound containing oxygen
7
Substance with pH below 7
8
Glass that splits light into spectrum
9
Disturbance that transfers energy
10
Curved glass that refracts light
11
Fourth state of matter
Down
2
Naturally occurring inorganic solid
3
Gas essential for breathing
5
Amplified beam of light
6
Group of similar cells