Discussion of the section on light and shadows
Here are some things to do to finish this section. Discuss these questions with the people in your group:
  1. If you wanted to study something very tiny, like a pinhead, could you use the technique of Shadows #2 activity to produce a large shadow of it? Explain what you have to do to get a nice big sharp shadow.
  2. Louise has a great idea how to decorate her living room for when she hosts the bridge club next week: she will draw hearts and spades on the light bulbs, so that they project these pictures onto the lampshade and the ceiling. Easy to do, cheap, and after the party she can just wash the pattern off. Margie objects, "If that works, why doesn't it say '100 Watts' on the ceiling already?" Is Margie right, that this won't work? Or can you tell Louise how to rescue the scheme?
  3. The shadow of the bottom of the flag pole is very sharp edged, while the shadow of the top end is rather fuzzy. Why? It might help to draw a picture showing how the sun and flag pole make a shadow.

    Here is another observation with the same explanation: To keep the sun from shining into my study I drew the blinds. But every blind has a hole for the guide rope, and these give a pattern of light on the wall, shown in the photograph. Why do we see a pattern of disks? Sometimes the disks overlap, to give the pattern shown at the right -- how can this happen?


These questions are a bit open-ended, and some people find them very confusing. We have provided some examples of good and bad discussions on a separate page. Please send us your discussion of two of these questions -- the one you are most sure about and the one you are least sure about (and tell us which is which!). Don't forget to tell us who is in the group. (Clicking on the link should start your email program, and fill in the address automatically. However, sometimes this does not work, or causes the wrong email program to be started. If the email link does not work for you, send the messages the way you are used to, to sciworks@pa.uky.edu --or reply a message from us!).

If there is something that you don't understand about light and shadows, Ask us!

This is the end of this section. (Check this box )   The next section is about diffraction gratings and the spectrum. However, there are several more pages you might want to look at sometime: