Teacher Notes

NOTE:This website contains activities that are intended for schoolchildren, grades 5 and up, under the supervision of adults. The Smithsonian Institution cannot be responsible for any accidents or injuries that may result from conducting the activity without proper supervision, from not following specific directions, or from ignoring the cautions contained in the text.

Description

Included is the description of a fairly simple, but wonderfully dramatic, chemistry demonstration. In this demonstration, you pour an oil solution into a glass containing another liquid. The oil and water don't mix but perch on top of each other. At the juncture is a third material (nylon) which you can extract from the jar in a long strand. The Student Activity Packet contains some background information, thought questions and a more detailed description of the demonstration.

The demonstration is safe and can be performed by a social studies teacher in a social studies classroom. You may want to have a science teacher help prepare the materials or serve as a demonstrator. The science department should dispose of the waste. Many chemistry teachers do a variation of this demonstration and prepared kits are available from companies that market science kits.

Duration (approximate): 1 class period (47 minutes)

Learning outcomes and skills

1. Students learn, through observation, that you don't have to plant, grow, shear or card a synthetic fiber. It is made in a laboratory and emerges from the test tube in a form that can be woven.

2. Students learn that nylon comes from petrochemicals and are reminded that synthetic materials use, and abuse, natural resources in different ways.

3. Students realize that scientific processes can be understood, on some level, by anyone and that science is not the sole preserve of white men in white coats.

Safety Notes For The Nylon Rope Trick.

1. The chemicals used (hexanediamine and sodium hydroxide) are toxic and need to be mixed under a fume hood in a laboratory. This should be done by the teacher. Care should be taken not to breathe in the fumes.

2. The chemicals will only be sold to a registered lab and demonstrator needs to obtain the MSDS (Materials Safety Data Sheets) and follow directions carefully.

3. Proper safety gear should be used while mixing chemicals and doing the experiment. Demonstrator should wear goggles, rubber apron, and rubber or plastic gloves.

4. Persons disposing of the polymer made in the experiment should carry out this procedure according to proper toxic waste program protocol. Pouring the chemicals down the drain will ruin the drains and cause environmental damage.

What You Will Need

Student Activity Packets which include a student handout

- goggles

- rubber gloves

- medicine dropper

- 2 small (50 ml) beakers or small clear glass cups

- pan of water

- paper towels

- a ten inch wire with a little hook on the end (can be made from a coat hanger)

- 1,6-hexanediamine (hexamethylenediamine)

- 20% sodium hydroxide or Hexamethylenediamine / sodium hydroxide solution

- cyclohexane or adipoyl chloride / hexane solution (adipoyl chloride / hexane solution is recommended)

- food coloring (if not using a solution)

If you need to order materials, you can contact the company listed below and order the smallest amount of the chemicals listed. You will get sufficient chemicals to do the demonstration about fifty times. The materials will cost about $60, but the chemistry department may already have some of them on hand.

Materials can be ordered from:

Aldrich
1001 West Saint Paul Ave.
Milwaukee, Wisconsin 53233
800-558-9160

The Nylon Rope Trick

Procedure for Demonstration

In the science laboratory, make the following:

1. Into a 50 ml beaker, pour first solution made up of 6 grams of hexamethylenediamine. Add 2 grams of sodium hydroxide solution. Then add 2 to 3 drops of red food coloring. OR -- If using hexamethylenediamine / sodium hydroxide solution, pour 15 ml of this solution into a 50 ml beaker. Omit the food coloring.

2. Make a solution of 5ml of adipoyl chloride and 5 ml cyclohexane. OR -- Measure 10 ml of adipoyl chloride / hexane solution. Pour this solution down the walls of the beaker (like pouring beer down the side of a glass to reduce the head). The two solutions will not mix and immediately a polymer will form at the liquid-liquid interface.

   In the Social Studies Classroom:

   Wear rubber gloves and don't let the chemicals touch your skin.

3. Using a ten inch wire with a hook at the end, gently free the polymer strings from the walls of the beaker (like taking the batter away from the sides of a mixing bowl).

4. Withdraw the wire with polymer strings attached and then hook the polymer strings at the center.

5. Gently raise the wire so that the polymer forms continuously producing a nylon filament that can be drawn many feet.

6. Rinse the filament several times in the pan of water and lay it on a paper towel to dry.

7. If you want to continue making nylon rope (and who wouldn't?) stir the remainder of the solution with the wire, let it settle, and start again.

8. Have the Science Department dispose of the waste.

Comments and questions to the Lemelson Center:lemcen@si.edu

Last Revision: 6/5/98