Across
1
Gas essential for breathing
4
Curved glass that refracts light
5
Fourth state of matter
6
Glass that splits light into spectrum
7
Blocking of light by a celestial body
11
Unit of force
Down
2
Chemical element in table salt
3
Amplified beam of light
8
Substance with pH above 7
9
Hottest planet in solar system
10
Substance with pH below 7