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Kiwi and Friends








Sink or Float

Cartesian Diver



Take a medicine dropper made of glass and adjust it in a glass of water so that it just floats.

 Place dropper in a water filled 2 liter plastic bottle and secure top.

Squeeze and release the plastic bottle and your diver will move up and down.

If you look carefully you will see the column of air in the dropper get smaller as you squeeze the bottle.





Kiwi barks at the moving medicine dropper



 For this demo you need a few raisins and a glass full of clear pop (7 up or Sprite)  Place raisins in the pop and watch them float and sink.

The raisins continue to bob up and down for a long time.

 You should be able to see the bubbles of carbon dioxide form on the raisins, lift the raisins and then pop as they hit the surface.  The raisin sinks and the bubbles start to form again.


Go to Sink or Float 2  for another buoyancy experiment,



Web sites

 Nucleation: Coke + Mentos

Cartesian Diver intro  Make a Diver out of a plastic straw and paper clips.





Cartesian Diver

Applet Diver

Cartesian Diver  with pen lid

Cartesian Diver The Movie

Submarines: How they Work

How Does a Submarine Work?


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A visitor has suggested using foil ketchup packets to make divers.  I haven't tried it yet.

The page has recently had  visits from Dartmouth Nova Scotia,  Danville Kentucky, Ankara Turkey,  Geneseo Illinois,  San Diego California, Park Ridge Illinois and Alexandria Virginia.

I last edited the page on February 13 2010.


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Last updated: 01/02/13.