Across
1
Center of an atom or cell
6
Tissue that contracts for movement
7
Push or pull on an object
10
Magnetic metallic element
11
Nerve cell in the brain
12
Absolute temperature scale unit
Down
2
Icy body with a tail near the sun
3
Blocking of light by a celestial body
4
Hottest planet in solar system
5
Glass that splits light into spectrum
8
Unit of energy
9
Precious yellow metallic element
13
Curved glass that refracts light