Across
1
Substance with pH above 7
3
Push or pull on an object
4
Force that attracts objects together
8
Center of an atom or cell
10
Ball of burning gas in space
11
Icy body with a tail near the sun
12
Smallest unit of an element
13
Amplified beam of light
Down
2
Group of similar cells
5
Molten rock beneath Earth surface
6
Solid with repeating atomic pattern
7
Naturally occurring inorganic solid
9
Reddish electrical conductor