Editing Standard Candles (section)

== Demonstration ==

1. At first, ask for two volunteers from the audience. Give each of them a flashlight and turn out the lights. Make sure each flashlight is set to the same, low-power brightness setting. First, have the volunteers stand at the same distance from the observer (the entire audience, if you have enough room, or just a third observer). Discuss observations.

2. Next have one of the volunteers move further away from the observer. Discuss observations.

3. Now have the far volunteer turn up the brightness on his flashlight so that it is much brighter than the near volunteer's. Discuss observations.

4. For the next demonstration, you can ask two new volunteers to hold the flashlights and a third to hold the red plastic wrap. This time have the two flashlight-holders stand at the same distance and turn out the lights. Make sure each flashlight is set to the same brightness setting and demonstrate this to the observer. Have the volunteer cover one of the flashlights with several layers of red plastic wrap - enough so that the difference in brightness vs the unobstructed flashlight is obvious. Discuss observations.

5. Now turn off the unobstructed flashlight. Remove some of the cellophane layers, or add more, to the obstructed flashlight. Discuss observations.