Physics unit 1

2. The surface of the earth
3. The unit of measurement of frequency
9. Change in direction of light
11. When an object is moving away from us and its wavelength becomes longer
13. The system where planets orbit the sun
15. Unit of measurement of for power
16. The theory that all planets orbit around the Earth
17. A type of lens that is curved on both sides to make it thinner in the middle
18. The colour that is best for absorbing heat
21. The theory that the universe has always existed
22. A type of wave that travels through the Earth
23. A change in the DNA caused by radiation

1. The second stage in the life of a star
4. The number of waves passing through a point per second
5. A type of wave where particles move at right angles to the direction the wave is moving
6. How good a device is at creating useful energy
7. The man who discovered ultraviolet
8. A type of wave where particles move back and forth in line line with the direction of the wave
10. Sound waves that are bellow 20Hz
12. Light that we can see with the naked eye
14. Flow of charged particles
16. Astronomer who helped disproved geocentric by looking at the moons of Jupiter
19. This has the smallest wave length on the EM-spectrum
20. Astronomer who discovered infrared