Caroline Imreibe

Snow Globe

Concept: Polarity, Hydrogen bonding. Water softener breaks the surface tension between sulfur and water.

Materials:

1.) Large beaker of water

2.) Flowers of sulfur ( you could substitute with talc powder)

3.) Calgon water softener (which is a solid).

You could substitute with a liquid detergent (make a solution that is half detergent and half water)

Directions:

1.) Fill beaker with water.

2.) Lightly sprinkle sulfur(or talc powder) onto the water.

3 A.) Add the Calgon water softener . Sulfur should sink.

or alternate procedure

3B.) dip several fingers into dishwasher detergent and then touch the surface with the sulfur powder. Be sure that you fingers touch some of the water solution.

Introduction:

It may not be cold enough, but today, (add Calgon) I'm going to make it snow!!!

Explanation:

Water molecules are polar so they join to resemble a screen. Since there is surface tension between the water molecules, the sulfur floats on top of the water. In addition, water is polar and the sulfur has the opposite property of non-polar, the two do not mix and the sulfur just sits on the surface of the water.

When the water softener, which is a type of detergent molecule, is added, it allows the sulfur and water to mix. The detergent has one end of its molecule that is nonpolar and it attracted to the sulfur which is also nonpolar. The other end of the detergent molecule is polar and therefore mixes with the polar water molecules. This bridges the water and sulfur together and decreases or breaks the surface tension of the water. This bridging then causes the sulfur to sink through the water because the sulfur is now more dense than the water. Finally the density of the sulfur is actually greater that the water and result in the sulfur sinking through the water.

Safety: Handle wet glassware cautiously.

Waste Disposal: Dispose of solution into sink.

Reference: Summerlin, L.R, Ealy. J.L, Chemical Demonstrations - A Sourcebook for Teachers, American Chemical Society, 1985, p. 135.