Description: This demonstration shows that an object with the same index of refraction as a liquid will look transparent when immersed in it.
- Lots of Wesson vegetable oil
- A large Pyrex beaker with as few markings as possible
- A small Pyrex beaker with as few markings as possible
- Paper towels
- Spread a few paper towels down where this demo will be used.
- Fill the large beaker up with Wesson vegetable oil, taking into account that the small beaker will also be going in later (so don’t fill it up all the way).
- When the professor is finished, pour the vegetable oil back into the main Wesson container.
- You will need to clean the Pyrex beakers out with soap and water.
- Show students the large Pyrex beaker. Explain that it has Wesson vegetable oil in it.
- Show them the small Pyrex beaker. Fill it up with the Wesson oil.
- Lower the small beaker into the large beaker, and note that it “disappears”.
- This is because the index of refraction of pyrex and wesson vegetable oil is about the same.
- Since the light does not bend, it’s as if there is nothing there, which makes it seem like there is only oil.
- A video camera can be used for lage classes. Point the camera at the side, since from the top the lid of the small beaker can be seen easier.