Across
1
Our home planet
4
Curved glass that refracts light
6
Unit of force
7
Magnetic metallic element
9
Icy body with a tail near the sun
11
Precious yellow metallic element
Down
2
Tissue that contracts for movement
3
Form of thermal energy
4
Amplified beam of light
5
Substance with pH below 7
8
Unit of power
10
Nerve cell in the brain
12
Force that attracts objects together