Let’s experiment with some lenses via PhET:

Let’s experiment with some lenses via PhET:

1. Select “Lens” from the simulation.
2. Play around a bit moving the pencil and observing how the image moves. Just get comfortable observing how the image reacts to moving the object.
3. Use the yellow reset button in the lower right.
   • Question 1: Describe the image of the pencil: is it larger or smaller than the object? It is closer or farther from the lens? If the image upright or inverted?
4. Move the object up and down only- without horizontal motion.
   • If you need to, use markers or the vertical ruler to help in moving the object up and down only.
   • Question 2: How does the image change? Does the size change? Does the image flip? Anything else?
5. Reset via the yellow button.
6. Move the object left somewhat.
   • Question 3: How did this affect the image?
7. Move the object to the right slightly.
   • Question 4: How did this affect the image?
8. Continue moving the object to the right until there is a large change.
9. Keep moving the object to the right until you can see the image again.
   • Question 5: What did you observe?
   • Question 6: This type of lens is the same kind found in a magnifying glass. Based on your observations, what is the best way to use a magnifying glass if your goal is maximizing the size of the image?
10. Reset via the yellow button.
11. Play with the index of refraction slider.
    • Question 7: What effect does index of refraction have on the ability of the lens to focus/bend light?
12. Reset via the yellow button.
13. Play with the radius of curvature.
    • Question 8: What effect does the curvature have on the ability of the lens to focus/bend light?
14. Reset via the yellow button.
15. Play with the diameter slider.
    • Question 9: What effect does lens size have on the ability of the lens to focus/bend light?
    • Question 10: With everything that you have learned, what qualities can improve glasses lenses?
      • Consider: the weight of the lens, you don’t want heavy glasses, the thickness of the lens, the amount of light that the lens captures etc