2B40.66 - Poly Density Bottle
Density demonstration. Spontaneous order arises out of apparant disorder in an unintuitive way and provides a deceptive breakdown of the Second Law of Thermodynamics.
For Lecture Hall Use: Pull out the Poly Density Bottles, a color camera, and a backplane.
In lecture hall, make sure camera output is visible to the audience. Then, Shake Shake Shake. Shake that bottle. Set it down and observe.
Distilled water and isopropanol alcohol are completely miscible with each other, because both molecules have -OH groups that easily form hydrogen bonds with each other. However, salt water and alcohol are not miscible with each other, and the salt ions Na+ and Cl- preferentially bind with the water ejecting the alcohol out of the aqueous solution. This causes alcohol to form on top and salt water on the bottom.
When the bottle is shaken, the two liquids mix forming a fake homogenous solution with a medium density between the two liquids. The white beads are the least dense and the blue beads are most dense, and so they float and sink respectively. As the two liquids seperate, as do their densities, the white beads fall from the top, and blue beads rise from the bottom.