A glass of water
A sunny day
On a sunny day, take a glass of water and place it in front of the window.
Place the white paper under the glass of water and observe as the sunlight passes through the glass.
You will see a rainbow on the white sheet of paper.
How does this work?
Rainbows are formed in the sky when sunlight passes through the raindrops. Similarly, in this situation, the rainbow is formed on the white sheet of paper after the sunlight passes through the water glass, splitting into 7 colours - red, orange, yellow, green, blue, indigo and violet.