#Take an empty glass cup. Place a coin in it and observe. Now ask the student to move backward till the coin becomes invisible. Now mark the position of the student. Now slowly pour water without disturbing the coin and ask student whether the coin is visible. | #Take an empty glass cup. Place a coin in it and observe. Now ask the student to move backward till the coin becomes invisible. Now mark the position of the student. Now slowly pour water without disturbing the coin and ask student whether the coin is visible. |