The purpose of this activity is to prepare a colloid and observe its properties.
This activity is appropriate for a general or first-year college-prep course. A "milk of sulfur" colloid is prepared and can be used to demonstrate the diffusion of light and non-separation of colloidal dispersions.
Approximately 30 minutes.
*See Modifications / Substitutions
Methyl alcohol is flammable and poisonous; avoid skin contact. Goggles must be worn throughout the activity.
- powdered sulfur*
- methyl alcohol
- Equipment: filter paper
- test tube
- Sulfur is available from a drugstore as flowers of sulfur.
It may also be purchased as commercial garden sulfur from a garden
shop or nursery.
- Methyl alcohol, also known as methanol, can be found in many
schools as duplicator fluid.
The preparation can be flushed down the drain with plenty of water.
This activity can be used to
study colloidal systems including their dispersion of light and
the Tyndall effect. Additionally, it can be used in conjunction
with solutions and suspensions to study the similarities and differences
Suerth, S. Margaret, Science
Teacher's Workshop, May,1968. A similar experiment is described
in this article.
- Dissolve 0.1 to 0.2 grams of powdered sulfur in 3 to 5 mL
- Shake the preparation for several minutes, then filter it,
catching the filtrate in a test tube containing approximately
15 mL of water. This will produce a sulfur-methanol-water colloidal
- Observe the system. Shine a light through the colloid and
observe the dispersion of light.
- Allow the mixture to stand and observe that the colloidal
suspension does not settle.
Submitted by S. Margaret Suerth
Woodrow Wilson Leadership Program in Chemistry
The Woodrow Wilson National Fellowship Foundation
CN 5281, Princeton NJ 08543-5281