Untitled Document

Physics Demo Number: 124

Approximate

Run Time: 5 min

Two Principles and Two Laws Illustrated by Means of a Cartesian Diver

Demo Description

Use a buoyant body in an enclosed volume of fluid to illustrate two Laws and two principles.

Scientific Principles

The Laws of Boyle and of Charles, and the Principles of Archimedes and of Pascal are illustrated.

Equipment

Cartesian Diver

Equipment Location

Kit (124) on [D-2-4].

Instructions

Archimedes' and Pascal's Principles, Boyle's and Charles' Laws are nicely shown by both the old and the new versions of a Cartesian Diver , as pictured on the left and on the right , respectively, in the picture.

Both live on [D-2-4] in Kit (124).

The old apparatus has a soft rubber stopper sealing its top. Strong thumb pressure applied to the stopper results in compression of the air bubble inside the pear-shaped diver with subsequent sinking of the diver to the bottom of the glass cylinder.

The newer version utilizes a 2-L soft drink bottle with a floating Tiger inside. Excess pressure applied anywhere to the surface of the bottle sends the Tiger diving.

Over a period of several weeks, the air bubble inside of each diver can be gradually absorbed by the water, resulting in permanently sunken divers. One must empty the containers and vigorously shake each diver in the room air, to return uncompressed buoyancy to each diver.