Hiding Fish | Hindi | Fun with Light
Channel: Arvind Gupta
Date: 2015-03-30

As you dip an empty bottle with a fish in a tank of water, the fish disappears. Why? Let’s investigate the mystery of the Hiding Fish. You’ll need a glass bottle, paper fish and a fish tank with water. Cut a fish from paper and color it. Fold and place the fish inside the empty glass bottle.
Now dip the empty bottle in the fish tank water. As the bottle dips in water the fish disappears. See this action again. On removing the bottle the fish reappears.
See this in close-up action. The fish disappears because there is air in the bottle and water outside. Because of different densities of air and water the light bends because of REFRACTION. The fish becomes visible on lifting the bottle because there will be air both inside and outside the bottle.
Now dip the bottle in water until the neck. Start filling the bottle with water and fish will reappear. This is because now there will be water both inside and outside the bottle.
Finally staple the fish to a piece of plastic straw. On dipping the fish in water you will still be able to see it. On lifting in air it will still be visible. Now place the fish and straw inside a plastic Zip lock bag. Fill the bag with little air. On dipping the bag in water the fish will disappear. On lifting the bag the fish will reappear. This work was supported by IUCAA and Tata Trust. This film was made by Ashok Rupner TATA Trust: Education is one of the key focus areas for Tata Trusts, aiming towards enabling access of quality education to the underprivileged population in India. To facilitate quality in teaching and learning of Science education through workshops, capacity building and resource creation, Tata Trusts have been supporting Muktangan Vigyan Shodhika (MVS), IUCAA's Children’s Science Centre, since inception. To know more about other initiatives of Tata Trusts, please visit www.tatatrusts.org