Magic Wool!



EQUIPMENT:

  1. A yarn of white wool
  2. Rubber gloves
  3. Metal washer
  4. A large cardboard box
  5. Two transparent drinking glasses
  6. Methyl salicylate (Can be found in science supply store or chemical shop)
[Warning – Be careful while handling methyl salicylate because direct contact can be harmful]

INSTRUCTIONS:

  1. At first wrap the white wool around the metal washer until it’s completely hidden by the wool.
  2. Leave at least ten inches of wool hanging off one end to make it easier to move the metal washer.
  3. Now place both transparent drinking glasses inside the large cardboard box so that if anything spills from the glasses the box can contain that.
  4. Pour about an inch of methyl salicylate into one of the transparent glasses wearing rubber gloves.
  5. Then hang the wool-wrapped metal washer into the methyl salicylate still wearing rubber gloves.
  6. Now wait for the wool to soak the methyl salicylate.
  7. After that carefully remove the wool-wrapped metal washer from the methyl salicylate and place it in the 2nd transparent drinking glass. Record its appearance if you wish.
  8. Now let the wool dry. Then you can record the changes if you wish.

RESULT:

  1. When fully soaked with methyl salicylate, the yarn of wool should look glassy and transparent. The metal washer should be visible through the yarn!
  2. When the methyl salicylate drains from the yarn of wool, it becomes normally visible once again.

EXPLANATION:

The experiment shows that, how the index of refraction of a material can be changed when it interacts with another different material. In our experiment, soaking the yarn of wool with the methyl salicylate gives the solid wool the same index of refraction as the liquid methyl salicylate. This makes the wool fibers appear to disappear.
As the methyl salicylate drains out of the yarn of wool, the index of refraction of the wool alters back to its original form. When the index of refraction do not match, the two different materials are visually distinguishable.


MORE EXPLANATION:

Light rays flows within different medium at different speed or velocity. Different medium resist the flow of light with different strengths. The characteristic that describes this property of a specific medium is called its refractive index or index of refraction.



OTHER EXPERIMENTS FOR YOU:
  1. Use nylon fiber instead of wool.
  2. Use polyester fiber instead of wool.  
  3. Use different other kinds of fibers.

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