Light and space review

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Across
  1. 4. The light-sensitive layer containing rods and cones at the back of the eye.
  2. 6. A lens shape that is thinner in the middle and spreads rays apart.
  3. 9. An instrument that collects light to make distant objects easier to observe.
  4. 11. A bowl-shaped hole formed when an object strikes the Moon’s surface.
  5. 12. The coloured part of the eye that controls the size of the pupil.
  6. 13. The force that attracts objects with mass towards one another.
  7. 15. A device that uses lenses to magnify very small objects.
  8. 18. An imaginary line through Earth from the North Pole to the South Pole.
  9. 19. The spinning of Earth on its axis, causing day and night.
  10. 20. A device that produces a narrow and precise beam of light.
Down
  1. 1. The opening through which light enters the eye.
  2. 2. Large, dark plains on the Moon formed by ancient lava flows.
  3. 3. A lens shape that is thicker in the middle and brings rays together.
  4. 5. An imaginary line drawn at a right angle to a surface.
  5. 7. The regular rise and fall of ocean levels caused mainly by the Moon’s gravity.
  6. 8. The bending of light as it changes speed between materials.
  7. 10. The clear front surface of the eye that protects it and begins refracting light.
  8. 14. Bright, mountainous, and heavily cratered regions of the Moon.
  9. 16. The path of one object around another object in space.
  10. 17. An uncrewed spacecraft sent to gather information about space.