Across
- 1. First part of any food chain (8)
- 3. Alloy of copper and tin (6)
- 5. Fall out of (10)
- 6. Evidence based on experience (7)
- 9. Stellar explosion (9)
- 10. Allows an object to float on water (8)
- 13. An object's resistance to change in motion (7)
- 15. 20th Element of the Periodic Table (7)
- 16. The layer of skin on the outside of the body (9)
- 17. Acid and base react to create this and water (4)
- 19. Type of variable that is measured (9)
- 20. A push or a pull (5)
- 21. Only person to win Nobel Prize in two scientific fields (5-5)
- 22. Turn liquid to solid (6)
Down
- 2. Animals that are active during twilight (11)
- 4. Changing direction of light through a lens (10)
- 7. A prediction of what will happen in an experiment (10)
- 8. Its two satellites are named Phobos and Deimos (4)
- 9. Smallest bone in human body (6)
- 11. Fluid's ability to resist flowing (9)
- 12. North-South lines of Earth's surface (8)
- 14. Plantae is one of these (7)
- 18. Used by astronomers to study stars and planets (9)