Across
1
Glass that splits light into spectrum
3
Unit of heredity
5
Ball of burning gas in space
8
Path of a planet around the sun
9
Absolute temperature scale unit
11
Particle of light
Down
2
Nerve cell in the brain
4
Icy body with a tail near the sun
6
Force that attracts objects together
7
Tectonic landmass section
10
Substance with pH above 7
12
Mass per unit volume