Across
1
Unit of energy
4
Unit of electric potential
5
Center of an atom or cell
8
Tectonic landmass section
9
Blocking of light by a celestial body
13
Force that attracts objects together
Down
2
Basic unit of life
3
Path of a planet around the sun
6
Element found in all living things
7
Second lightest element
8
Particle of light
10
Naturally occurring inorganic solid
11
Gas essential for breathing
12
Compound containing oxygen
14
Amplified beam of light