Extending Sight

What makes human eyes unique is the brain, which gives us the power to extend the mechanics of vision. With telescopes and microscopes, we see to the stars and into the living cell.

In 1614, the Italian scientist Galileo was amazed when he looked through one of the first microscopes: “I have seen flies which look as big as lambs and have learned that they are covered over with hair and have very pointed nails by means of which they keep themselves up and walk on glass, although hanging feet upwards, by inserting the point of their nails in the pores of the glass.”

“I discovered living creatures in rain…they sometimes stuck out two little horns, which were continually moved after the fashion of a horse's ears. I imagine that ten hundred thousand of these very little animacules are not as big as an ordinary grain of sand.”

–Anton von Leeuwenhoek, 1675

Can you match each picture with what it is?

  1. A: a butterfly wing
  2. B: a rose petal
  3. C: a grain of pollen
  4. D: an insect
  5. E: butterfly eggs on a raspberry
  6. F: tooth decay
  1. 1: a round object with many points
  2. 2: a small animal with antennae
  3. 3: surface of an object with cracks in it
  4. 4: rows of fluffy-looking rectangular objects
  5. 5: rows of rounded, reddish-orange objects with ridges on them
  6. 6: hollow, blue-gray cylinders on a fuzzy, grass-like surface



Being the only one of its kind.

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  1. Why is it important to be able to magnify different objects?
    [anno: Answers will vary but could include that by magnifying objects, people can know more about what makes up an object.]
  2. Think about how tiny human cells are. Think about how far away other planets and stars are from Earth. What are some things scientists have learned by using microscopes and telescopes? Name two kinds of things scientists may have looked at with telescopes or microscopes. Tell why these things are important to study.
    [anno: Answers will vary but could include that scientists have been able to look more closely at how human cells change in response to medicine. Students may mention that scientists have learned a lot about the universe by studying the planets and the Sun through telescopes.]