![]() ![]() You should have to move your hands about twice as often as in the lowest frequency resonance you created before.Ĭount the frequency: 1,2,3,4,1,2,3,4. In other words, the slinks bunch up near one hand while they spread out at the other.įind a higher frequency resonance of the longitudinal wave in which you move both hands in the same direction (anti-clap). The high pressure hand becomes a low pressure and vice-versa. Notice also that when one hand is at high pressure the other is low. The hand-held ends are antinodes of pressure. ![]() At the nodes of motion near your hands however the slinks bunch together and then spread apart: the pressure changes a lot. The center is an antinode of motion but a node (a place with no change) of pressure. Notice that in the center the slinky moves back and forth but the spacing between the slinks near the center does not change. The flag marking the center whips back-and-forth. Notice that the center of the slinky is an antinode, your hands are nearly nodes. Find the frequency of hand motion that produces the largest motion of the center of the slinky for the smallest motion of your hands. Notice the motion of the slinky which is called longitudinal motion. (One of our teachers described this as the sound of one hand clapping twice.) Move both hands in the same direction, if the slinky stretches right-left move both hands to the left then to the right. Notice that the pressure change is greatest at the center where the slinks alternately bunch-up and spread apart, and where the side to side motion of the flag is the least. Let's call closely spaced slinks high pressure and widely spaced slinks low pressure. When the slinks are far apart ,the slinky models low pressure in a gas. When the slinks are jammed close together the slinky models high pressures in a gas, where the atoms are closer together. Next notice the spacing between the slinks (turns) of the slinky. You can attach a small flag of masking tape to the center of the slinky to make it easier to see that the center is not moving. Your hands move a lot while the center of the slinky moves very little. Move your hands together and then apart, just as if you were clapping. Stretch the slinky to between 1 and 2 meters long. Grab the ends of the slinky in your hands. If you use a table top, use only 1/2 of a plastic slinky, otherwise friction will make the experiments difficult. ![]() Optional, rest the slinky on a smooth table top. Pull the chairs apart until the line is taut. Slide the slinky onto the fishing line, and then tie the other end of the fishing line to another chair. Again, if you have trouble, try this on a tabletop.Ĭount the rhythm every time your right hand hits bottom-1, 2, 3, 4, 1, 2, 3, 4, etc. Notice that your hands move a large distance while the center of the Slinky hardly moves at all (see illustration below). Try moving your hands in opposite directions-that is, move the right hand up when the left hand moves down and vice versa. Notice that the center portion of the Slinky moves up and down the most and the portions nearest your hands the least. If you have trouble, try doing this same experiment using a side-to-side motion on a table top). Count the rhythm every time the middle of the Slinky hits bottom-1, 2, 3, 4, 1, 2, 3, 4, etc. Find the lowest frequency that produces the largest motion of the Slinky using the smallest motion of your hands (this should be about one cycle per second.) One large hump-half a wave-should appear, moving up and down on the Slinky (see illustration below). Move both of your hands up and down together. Hold the Slinky between your hands-it will be horizontal and will sag. ![]()
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