Science activity inKindergarten No. 240

Warsaw, Poland04.2012

Polymers around us

1. Building polymer model

• Explain to the children where they use polimers (eg. plastic cups, chairs, toys).

• Using paper clips build 3 chains. Explain that plastic is made from chains of polymers.

2. Teflon messages

• Cut a piece of Teflon Tape than write a secret message on the tape with the marker.

• Stretch the tape from top to bottom, making your message taller, not longer.  Pull carefully so that you don’t tear your message. 

Suddenly you can’t read your message anymore!  Give the message to a friend and see if they can figure out how to make the letters their original shape again.• Pull on the tape from end to end making the letters short again.When you are done pulling the tape, message will look normal again.

Explanation:Teflon Tape is a type of polymer called polytetrafluoroethylene (PTFE). This is a kind of polymer that has long chains of molecules lined up side-by-side and on top of each other. If you try to stretch the tape end to end before stretching it from top to bottom, you won’t be able to stretch it much at all. That is because the polymers are bonded to each other very tightly.  But, there are lots of chains stacked on top of each other. These stacks make it possible to pull the tape from top to bottom and stretch your secret message. When the polymer chains are pulled from top to bottom they slide over one another and reduce the number of chains in a section without breaking the chains themselves. When the tape is pulled back end to end, the chains are realigned and your message is legible again.

3. „Smelly" balloons

Some materials are more porous than others. Compare how porous different kinds of balloons. Put an drop of extract in ballon (eg. vanilla extract, deodorant etc). Then blow a balloon. Give it to the children. They discover that balloon smell. Although balloons are not engineered to have particularly porous membranes, it will be interesting to observe that particles travel through the membrane and we are able to smell for example vanilla odour.

4. Vanishing styrofoam

Use a solvent like acetone to show that polystyrene packaging material is mostly air. The acetone easily dissolves the polystyrene, leaving very little residue. Put a styrofoam in acetone.

Safety Notes: Experiment should be perform by a teacher. Do not swallow acetone. Use it in ventilated rooms. May cause eye irritation. Wash an eye with water Experiment should be perform by a teacher. Longer exposure to skin may cause skin irritation.

5. Thirsty polymer

Children predict how much distilled water can be poured into 1-2 spoons of polyacrylate, the absorbent polymer in disposable diapers.

Materials Needed:2 spoons, sodium polyacrylate, 400-mL graduated cylinder or a cup, distilled water

ProcedureTalk with children about how polymers can be changed to make them useful for different tasks. What properties would you want a polymer to have if it was going to be in a diaper? Absorbent, safe, etc. This next demonstration and experiment deals with the polymer used in diapers called sodium polyacrylate. We are going to explore the absorbency of this polymer. Teacher put 2 spoons of sodium polyacrylate in measuring cylinder. Then asks how much water it could absorb. Then pour water and mix it well. Sodium polyacrylate should absorb more than 300 ml of water. Safety Notes: Do not swallow sodium polyacrylate. Experiment should be perform by a teacher.

6. Bouncing ball

Introduction The bouncing ball in this activity is made from a polymer. Polymers are molecules made up of repeating chemical units. Glue contains the polymer polyvinyl acetate (PVA), which cross-links to itself when reacted with borax. Materials Needed:borax (found in the laundry section of the store) white (makes a non-transparent ball) or blue or clear school glue (makes a translucent ball) warm water food coloring (optional)ziploc bagpaper towels

Procedure

• Pour 2 tablespoons warm water and 1/2 teaspoon borax powder into the cup labeled 'Borax Solution'. Stir the mixture to dissolve the borax

• . Add food coloring, if desired.• Pour 1 tablespoon of glue into the cup

labeled 'Ball Mixture'. • Add 1/2 teaspoon of the borax solution

you just made Stir carefully. • Take the white substance out of the cup

and start molding the ball with your hands. The ball will start out sticky and messy, but will solidify as you knead it.

• Plastic ball can be stored in a sealed ziploc bag.

Children from Kindergaten No. 240