Please help . Have a subject stand one foot away from a wall in a dark room. Have an assistant stand 10' back from the wall and shine the light at the friend's head. Observe the shadow's darkest (umbra) and lightest area around the edges of the shadow (penumbra). Measure the width of the penumbra. Measure the umbra. Record your data. Have the assistant with the light move 3 feet closer to the subject and shine the light on the subject's head. Measure the penumbra and umbra at this distance. Record your data. Have the assistant move another 3' closer. Repeat the measurements and record the data in a table like below.
a chart
2. Now have the subject stand one foot from the wall and the assistant 10' from the wall again. Starting a new list of data measurements list the shadow readings you took before at this distance. Now, the assistant with the flashlight stands stationary and the subject moves closer to the assistant and away from the wall towards the flashlight by 3'. Measure the umbra and penumbra and record the data. Have the subject move towards the light and away from the wall by another 3'. Measure and record data in the table.
3. Based on your observations and data what happens to the umbra and penumbra when the assistant moves closer to the friend standing next to the wall? What happens to the umbra and penumbra when the friend moves away from the wall and towards the assistant who remains stationary? When the assistant moves closer is rate that the penumbra and umbra change more, equal to or less than when the friend moves closer to the light and away from the wall?
4. Draw two diagrams showing the results of your data. One diagram should show what happens when the friend remains stationary and the light moves closer to the wall. The other diagram should show what happens when the friend moves away from the wall and the light remains stationary. Explain the results. Hint: Think about the light angles relative to the subject and the wall.
Once you have completed the experiment, recorded your results, and answered the questions, turn in your completed experiment here.
