ARBOR SCIENTIFIC 33-0140 Helical Spring Instruction Manual

: June 11, 2024
: ARBOR SCIENTIFIC

Table of Contents

Contents
Background
Activities
Related Products
Documents / Resources

33-0140 Helical Spring

ARBOR SCIENTIFIC 33 0140 Helical Spring Instruction Manual

Background

The snaky is a long, helical spring that can be used to demonstrate waves and other phenomena. A mechanical wave is a disturbance that moves through a medium. The snaky can demonstrate longitudinal and transverse waves. The particles move parallel to the direction of the wave in longitudinal waves. The particles move perpendicular to the direction of the wave in transverse waves.
With the snaky, you can also demonstrate standing waves. Standing waves appear to be stationary because of interference. With the snaky and a rope, you can also show what happens when a wave enters a new medium. The snaky can also be used to demonstrate Hook’s Law and harmonic motion, and even Hubble’s constant.

Safety Information
The snaky should be handled carefully. If one or both ends are released while stretched, the spring can snap back quickly, possibly causing injury. Never let go of the spring unless it is slack.

Activities

Most of the activities are best done on a tile floor. It keeps the motion in two dimensions and gives a convenient reference. Also, if the spring is accidentally let loose, it is less likely to hit someone in the face.

Longitudinal and transverse waves: You can put a piece of tape on the spring to better show how the individual parts of the spring are moving. Stretch the spring lightly across the room. For transverse waves, strike and shake the spring side to side. For longitudinal waves, gather up several coils of spring and then let go.
The speed of a mechanical wave depends on the medium through which it travels: Stretch the spring lightly across the room. Measure the time that it takes for one pulse to make one complete trip – back and forth – down the spring. Have the students predict methods to make the wave move faster, i.e. hit the spring harder, etc. The only way to make the wave travel faster is to stretch the spring more, changing the medium. This can also be done with two springs side-by-side as a race. Have one team of students change something to try to make their wave beat the other team’s wave.
Interference: Have two students at opposite ends of the stretched spring hit the spring to the side. Watch what happens at the place where the two pulses meet. Also, watch what happens to the original pulses after they pass through each other. Try having the students hit the spring on the same side and opposite sides. Also, have them hit the spring with different amounts of force in both directions.
Standing waves: Shake the spring slowly back and forth, adjusting the speed until you get one antinode in the middle of the spring. Try to get 2, 3, 4, etc. antinodes. How many can you get? The students can touch the spring at the node with a finger without disturbing the wave, but touch it anywhere else and the motion will be dampened. Also, try this with the rope attached to the other end. You will get an antinode at that end. Show the difference between guitar strings and clarinets this way.
Harmonic motion: Using the same setup as above, pull a light mass down a few centimeters and let go. It should bob up and down harmonically. You may have to try a few different masses and a few lengths of spring to get it to sustain motion.
Hooke’s Law: Use a clamp to hold the spring. Have ¼ meter or so extend below the clamp.
Hang hooked masses from the spring. Show that there is a linear relationship between force applied and distance extended. (Be careful not to exceed the elastic limit.)
Expansion of the universe: How can everything be moving away from us, even if we’re not in the middle of the universe? How can astronomers estimate distances from speed? Take the snaky and put five or so pieces of paper along the length of it. It does not matter exactly where they are. Pick one of them to be the Earth; the others are galaxies. With the snaky held lightly between two people, measure the distances between the notes. Put a table of the distances on the board. Have the two people holding the spring take a step backward. Measure the distances again. Have them take another step back and measure again. With the table that you now have, show that the galaxies that are farthest from the Earth are moving away from the Earth the fastest (moved the most distance in the time).
Earthquakes and elastic rebound theory: Attach the snaky to a box or other weighty object.
Put the object on the floor (carpet works best). Pull the snaky slowly to the side (You can grab the snaky in the middle.) If there is enough friction between the object and the floor, the object will stick for a while, then suddenly move. Keep going. It will jump, again, but maybe not as much or more than before. This shows that as the tectonic plates slide past each other, they stick. When enough stress builds up, the plates suddenly move: an earthquake. You will need to find the right size, weight, and material for your box. Otherwise, it will slide too easily, or jump too much.

Spring Wave (P7-7220) Use this highly visible Spring Wave to observe phase reversal at the fixed end of wave pulses and to test fundamental and multiple vibrations. Expands 20in to 12ft Resonance Bowl (P7-7510) See water dance to the vibrations from your hands with the Resonance Bowl! A fun and effective way to demonstrate the behavior of waves and their interactions.
Mechanical Wave Complete Bundle (P7-1100) The Arbor Scientific Mechanical Complete Bundle comes with everything you need to drive wave experiments and harmonic and motion demonstrations with ease and accuracy.

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