Where Is The Glass?

TLSCB005

In his school, Jugaadu learned that the Refractive Index of glass and oil is the same. He wants to explain it to his other friends practically. How he can so that?
science kit
  1. Take the big glass and small glass tumbler.
  2. Place small glass tumbler into the bigger one.
  3. Pour oil into the glasses.
  4. When glasses filled with oil the smaller glass will get disappeared.