Lose a Glass in a Glass

Use this activity to demonstrate the role of indexes of refraction in our ability to differentiate the appearance of different materials. Note: adult supervision is recommended for this activity because it involves paint thinner.

Required Materials

  • A clear glass jar free of labels or other marking patterns
  • A smaller clear jar that fits inside the larger one
  • Paint thinner - also known as petroleum distillate (Caution: We suggest that you use this substance only with an adult present - it is poisonous and can also burn your skin or eyes. Use in a well-ventilated place because the fumes can be harmful. Be sure there are no open flames in the room, as this substance is flammable.)

Activity Directions

  1. Put the smaller jar into the larger one.
  2. Fill the smaller jar and the space between the two with paint thinner.
  3. The small jar seems to simply disappear.
  4. When you are finished with the experiment, carefully pour the paint thinner back into its original container and seal tightly.