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Part of Hall of Ocean Life.
In this hands-on experiment, students create a neutrally buoyant "diver" and then observe the effects of increased water pressure.
What you need:
What you do:
What's the meaning of this?
Ask students if they can explain what makes the diver sink. Ask students: "Does the amount of air in the balloon change?"
This activity demonstrates the property of buoyancy. An object is buoyant in water due to the amount of water it displaces or "pushes aside."
When students squeeze the bottle, they increase the pressure inside the bottle. The air in the balloon is compressed and reduced in volume, the diverbecomes less buoyant and sinks. Stress that the amount of air stays the same, even though its volume has changed.
Fish keep themselves from either sinking or floating to the surface by using muscles to squeeze or relax a small sac (with a small air bubble inside) in their bodies. By squeezing the sac smaller, the fish will sink. By relaxing their muscles, the sac increases in size, displaces more water, and a fish will begin to rise to the surface. This same principle is used to control the buoyancy of a submarine. By pumping water in and out of tanks stored in the submarine, a submarine can be made to rise and sink.
Instead of a balloon, the "Deep Sea Divers" experiment can be done with a medicine dropper.
What you do:
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