Across
1
Mass per unit volume
3
Reddish electrical conductor
7
Naturally occurring inorganic solid
8
Force that attracts objects together
9
Fourth state of matter
10
Disturbance that transfers energy
Down
2
Tectonic landmass section
4
Smallest unit of an element
5
Infectious microscopic agent
6
Center of an atom or cell
11
Curved glass that refracts light