Building a better Guinea and Feather

Step 16 Objects

At first I was planning to use a replica of a British guinea but they're only about an inch in diameter and that's too small to be very visable. The aluminum disk was originally the guinea from the old dual tube apparatus shown earlier. I simply reused it when the old apparatus broke.

I was also going to use real feathers, but there was too much static cling between them and the acrylic tubes. The bright pink and green paper is much more visable anyways.

Both the aluminum and paper disks have a diameter of 1.75" (the tube ID is 2.25"), but the mass of the aluminum disk is over 60 times greater. This combination of the metal and bright paper disks works quite well because the metal makes a loud thud as it hits the bottom of the tube, and the paper is large enough to be seen fluttering down. When the air is pumped out, you can still hear the aluminum disk land, but you can see that the paper lands at the same time. Just watching the paper, it can appear as if the paper is making the loud thud even though it's really the aluminum disk landing at the same time.

The electronic scale was surplus equipment which is why it has a Do Not Use sticker. It still works fine and is accurate even if the calibration isn't official.