Across
- 3. the study of life in the universe
- 4. stands alone and isn't changed during an experiment
- 7. process where cold water rises to the surface
- 10. the amount of mass per unit of volume
- 12. distance light travels in one year
- 17. weather patterns and ocean currents
- 18. water in or from the sea
- 19. emission of light from living organisms
- 20. theory explaining how universe originated
Down
- 1. the amount of salt present in water
- 2. these lines run east to west (horizontal)
- 5. changes as a result of the independent variable
- 6. these lines run north to south (vertical)
- 8. an educated guess
- 9. scale for measuring wing speed
- 11. winds carrying heavy rains
- 13. a large system of rotating ocean currents
- 14. result of earth's rotation
- 15. slow movement of earth's axis
- 16. rain, sleet, hail, snow