Across
1
Glass that splits light into spectrum
3
Naturally occurring inorganic solid
5
Gas essential for breathing
7
Particle of light
8
Second lightest element
10
Fourth state of matter
Down
2
Nerve cell in the brain
3
Measure of matter in an object
4
Force that attracts objects together
5
Path of a planet around the sun
6
Element found in all living things
9
Molten rock beneath Earth surface
11
Our home planet