Saturday, June 26, 2010


PURPOSE : To demonstrate diffusion and osmosis .

MATERIALS : Eye dropper
                          Vanilla extract
                          Balloon ( use small size )


  •  Place 15 drops of vanilla extract inside the deflated balloon. Be careful not to get any of the vanilla on the out side of the balloon.
  •  Inflate the balloon to a size that will comfortable fit inside the shoebox and tie the open end .
  • Place the balloon in the empty shoebox . Leave the balloon in the closed box for one hour .
  •  Open the box and smell the air inside .

RESULTS : The air smells like vanilla . The box is still dry .

WHY ? The balloon appear to be solid , but it actually has very small invisible holes all over its surface .The liquid vanilla molecules are too large to pass through the holes , but the molecules of vanilla vapor are smaller than the holes and pass through . The movement of the vapor through the rubber membrane is called osmosis .

The escaped vanilla vapor move through the air in the shoebox . And once the shoebox is open , through the air in the room . This spontaneous movement of molecule from one place to another is called diffusion . If u wait long enough , the diffusion will result in a uniform mixture of the vanilla vapors and the air with which it mixes .

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