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A simple way to simulate the feather and the farthing demonstration can be done with a loonie and a paper disk.
Cut a small disk from a piece of note paper so that it is slightly smaller in diameter than the loonie. Sit the paper disk on top of the loonie. You should to be able to see the edge of the loonie all the way around the paper disk. If not, trim the disk slightly to allow you to see the entire circumference of the loonie.
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Next, balance the loonie and the paper disk on your finger and hold them perfectly level. Finally, pull your finger briskly out from under the loonie, being careful not to tilt or bump the loonie.
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If you have done this correctly, the loonie and the paper disk will fall to the floor at exactly the same rate. The reason for this is that all objects accelerate at the same rate unless air friction interferes with the motion of the falling objects. In this case the loonie effectively blocks the air flow from hitting the paper disk and both fall to the ground at the same rate. |
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What made Commander Scott's "Hammer and Falcon Feather" demonstration amazing was that it had profound implications, both scientifically and historically.
Scientifically, it demonstrated the universality of the gravitational laws discovered by Galileo and later mathematically formulated by Newton.
Historically, Commander Scott's demonstration was the first (and so far, only) time that a human had personally emulated, on another world, one of the most important scientific discoveries in the history of our world.
The photo above shows the feather and the hammer after being dropped by Commander Scott. The hammer is partially hidden in the deep shadow.
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The Hammer and the Falcon Feather demonstration was video taped and the images transmitted back to Mission Control.
The procedure was fairly simple. Commander Scott held the feather in one hand and the hammer in the other hand, both at the same height (approximately one metre) above the lunar surface. At precisely the same instant both the feather and the hammer were released and the results recorded. Analysis of the video tape provided the information for this activity. |
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The diagram (left) shows information extracted from the video tape of the demonstration.
The most obvious aspect of the video is that both the feather and the hammer fell at exactly the same rate. They dropped exactly side by side, both reaching the lunar surface at precisely the same instant. Using the frame rate of the camera for timing information, measurements were made at 0.36 second intervals and the distance fallen was measured. The results of these measurements are shown in the diagram. The total time to fall 1m is almost exactly 1.08s. |
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From rest (zero speed) the average acceleration a that a body experiences over a distance d is
where t is the elapsed time.
Using the equation above and measurements from the diagram, calculate the local acceleration due to gravity on the Moon's surface. Average your results.
| elasped time (seconds) | distance fallen (metres) | acceleration (m/s2) |
|---|---|---|
| 0.36 | 0.11 | 1.69 |
| 0.72 | 0.46 | 1.77 |
| 1.08 | 1.00 | 1.71 |
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