Across
1
Particle of light
5
Biological catalyst
6
Glass that splits light into spectrum
7
Tissue that contracts for movement
10
Chemical element in table salt
13
Magnetic metallic element
Down
2
Curved glass that refracts light
3
Second lightest element
4
Path of a planet around the sun
8
Measure of matter in an object
9
Blocking of light by a celestial body
11
Icy body with a tail near the sun
12
Basic unit of life