Polyox

Objectives

• Investigate the properties of a self-siphoning fluid.

• Describe the structure of polymers

Materials

• Per Demo or Class:
  two 600 mL beakers
  polyethylene oxide (polyox) *
  scale to measure 3 to 4 grams of polyox
  alcohol
  corn syrup
  eggbeater or mixer

  * Can be found at Teacher Source or online as Poly-Ox or Siphoning Gel.

Key Questions

• How does the poly-ox gel behave differently from the corn syrup?
• If the beaters were in a powder would the powder climb the beaters or move away?
• What if the beaters were in a bowl of long threads?

What To Do

Before demonstration:

1. Pour 3 to 4 grams of polyox powder into a 600 mL beaker.
2. Add 25 mL of alcohol and swirl until the powder is completely wet.
3. Add 350 to 400 mL of water in one pour. Stir vigorously until it gels completely.

During demonstration:

1. Take the unused 600 mL beaker and fill half-full with corn syrup.
2. On the first speed setting, beat the corn syrup using the mixer. Ask students about any observations they can make about what is happening with the corn syrup. (The corn syrup is thrown away from the beaters).
3. Now use the mixer with the polyox gel. Ask students to predict what could happen. (The gel will climb the beaters. Soon the whole gel mass is on the beaters)

Extensions

• Try pouring polyox gel from one cup to another. The goop will lift itself out of the top cup to flow down into the bottom one. Polyox is a shear thinning non-Newtonian fluid (like ketchup), this means in a bottle it won't flow out easily unless shaken, squeezed, or smacked. Give it a go!