1Q60.25 - Euler's Disk
A look at the motion of a spinning disk on a smooth surface. "Spolling; the combination of spinning and rolling."
Obtain Euler's Disk set up. The box is located on the top shelf of the mechanics shelf. Remove concave mirror and Euler's disk. Clean mirror with windex (if surface isn't clean, Euler's disk will lose energy much more rapidly).
Clean mirror with windex (if surface isn't clean, Euler's disk will lose energy much more rapidly). With the concave mirror placed firmly on a hard flat surface, spin the disk so that it spolls on its machined rounded edge. While the disk spins, friction and vibrations are present. As a result, the disk is losing energy and as it slows down, we can observe the frequency of the sound made by the disk as it slows down.
Euler's Disk is a chrome plated steel disk that is 1/2" thick and 3" diameter. One edge is machined to a smooth radius. A concave mirror base provides a setting for Euler's Disk to spin like a coin.
Conservation of energy: When Euler's Disk is spun, the disk contains both potential and kinetic energy. The potential is given to the disk when it is placed on its upright side. The kinetic energy is given to the disk when it is spun on the mirrored base. Euler's disk would spoll forever if not for friction and vibration.
Conservation of angular momentum: Like a top, Euler's Disk uses its angular momentum to hold itself upright. As the disk spolls around in a circle it is held in place by a balance of the gravitational force pulling the disk down and the force applied by the mirror base which holds the disk up.
Spolling is very efficcient. At approximately 15,000rpm, Euler's disk consumes the energy of a 100W lightbulb.