Science Crossword

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Across
  1. 2. substance that has two or more elements in it
  2. 4. does not allow water to pass through
  3. 7. does not allow light through
  4. 10. our planet
  5. 12. earth's star
  6. 17. active during the night
  7. 18. weather conditions
  8. 19. substances used in chemistry experiments
Down
  1. 1. unit of energy or work
  2. 3. top layer of land on the Earth's surface
  3. 5. it is measure in Newtons (N)
  4. 6. belonging to or living in water
  5. 8. single celled organism
  6. 9. group of atoms
  7. 11. Mixture of 2 or more metals
  8. 13. everything that exists
  9. 14. how much room something takes up
  10. 15. found in the nucleus
  11. 16. living beings that fly
  12. 20. Helps us breathe