Across
1
Unit of force
4
Form of thermal energy
7
Force that attracts objects together
8
Compound containing oxygen
11
Mass per unit volume
12
Fourth state of matter
Down
2
Naturally occurring inorganic solid
3
Path of a planet around the sun
5
Gas essential for breathing
6
Nerve cell in the brain
9
Infectious microscopic agent
10
Tectonic landmass section