Discussion Question 1:

When washed dishes aren't rinsed well. they often show a display of colors after they are dry. What causes this?

Discussion Question 2:

When you look at a window-glass "mirror" at night, two similar images, one behind the other, are often seen. Why are there two images?

Discussion Question 3:

A halo or ring is sometimes seen around the moon or Sun as a result of high thin cirrus clouds that are composed of ice crystals. What causes these halos? (Hint: Keep in mind that the clouds are between the light source and the observer