Wednesday, July 7, 2010

WATER DROP LENS

PURPOSE : A water drop is used to simulate an eye lens.

MATERIALS : One 6 inch (15 cm) piece of 20 gauge wire
                           Pencil
                           Bowl
                           Newspaper

PROCEDURE :
  • Twist one end of the wire around the pencil to make a round loop.
  • Fill the bowl with water.
  • Dip the wire into the water with the open loop pointing up.
  • Lift the loop carefully out of the water and hold it over the newspaper. You want a large rounded drop of water to stay in the hole of the wire loop.
  • Look through the water drop at the letters on the page. You may have to move the loop up and down to find a position that makes the letter clear.
RESULTS : The letters are enlarger. If the letters look smaller dip the loop into the water again.

WHY ? The water drop is curved outward and acts like a convex lens. This type of lens is used as a magnifying lens and is the type of lens is eyes. Sometimes the water drop stretches so tightly between the wire that it curves downward forming a concave lens. This type of lens causes the letters to look small. 

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