Did you ever notice how a big plate of spaghetti clumps and sticks together? But if you add sauce, or olive oil, the spaghetti loosens up so you don't end up with your entire meal on your fork? Well, plastics are just like spaghetti -- they just don't taste as good.
Plastics are made up of different kinds of polymers, which are long chains of molecules.
Polymers act like the spaghetti -- they wiggle around and stick together.
Try a few experiments, courtesy of the National Plastics Center & Museum, to explore these sticky polymers.
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Stick It to a Balloon
Materials needed:
- latex balloons
- vegetable oil
- wooden skewers
Instructions:
- Check with a grown-up before you begin.
- Blow up a balloon almost all the way, and tie a knot to close it.
- Dip the pointy tip of a skewer into the vegetable oil.
- Carefully -- and gently -- twist and push the skewer into the broad end of the balloon.
- If you've made it this far (without popping), continue to push the skewer through to the other end, near the knot of the balloon.
How many skewers can you get into one balloon?
Latex is a polymer that exists in nature. The latex polymers in a balloon squirm around to allow a skewer to pass through them. The molecules are stretched out further when you inflate the balloon fully and are more likely to snap, which would make the balloon pop.
Try the next activity to see if artificial polymers act the same way.
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Skewered Sandwich Bag
Materials needed:
- sandwich bags that you can seal shut
- water
- vegetable oil
- wooden skewers
- sink or large basin
Instructions:
- Check with a grown-up before you begin.
- Fill a sandwich bag with water and seal it.
- Dip the pointy tip of a skewer into the vegetable oil.
- Do this step over a sink or a basin. Carefully -- and gently -- twist and push the skewer into through the bag of water.
- See if you can stick the skewer through the bag without getting wet.
Hmm... maybe "a large towel" should be added to the list of materials needed...
The polymers in the bag are synthetic, which means they're artificially created. They share the same properties as the latex polymers and thus, you're able to jab at them without spilling (hopefully).
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Slime Alert!
All right, you're itching to make some gooey slime. Who can blame you?
First things first -- make sure you've got some old clothes on and that you prepare your work space. Maybe you should lay down an old sheet or some newspapers to protect rugs or floors.
Materials needed:
- clear glue gel (not white glue)
- distilled water
- a microwave oven
- borax, a mineral used for cleaning -- it's sold alongside laundry detergents.
- food coloring (make sure you have green!)
- wooden mixing sticks -- find them at arts and crafts stores, or hardware stores.
- three mixing bowls
- rubber gloves (recommended)
- waxed paper
Instructions:
- Check with a grown-up before you begin.
- Use a wooden mixing stick to stir together 1/2 cup of glue with 1/2 cup of water in one of the bowls.
- Microwave the mixture on high for one minute.
- Stir the mixture again.
- Microwave it on high for one more minute.
- Stir it until it's smooth, then put it aside.
- Measure 2 tablespoons of borax and add it to 1 cup of water in another bowl.
- Stir until all of the borax is dissolved.
- Mix 1/2 cup of the glue mixture with 1/2 cup of the borax mixture in a third bowl.
- Add 5 or 6 drops of food coloring (green or orange are particularly yucky).
- Mix the whole goopy mess together.
- Pull on those rubber gloves! Put your slime on some waxed paper and knead it like bread dough.
Congratulations! You've got slime. You can save it in a plastic bag in the refrigerator -- just make sure you label it so no one eats it!
The borax connects the glue molecules, resulting in long connected chains of molecules. Did someone say "polymers"?
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My Buddy, Putty
Here's a variation -- make a bouncy, rubbery type of slime.
Follow instructions for the slime-making activity above, but use white glue instead of glue gel.
Test to see if it's different from the other slime. Does it bounce more? Stretch more?
If you've made it this far, you are a Plastics Pro!
Want to tinker around with plastic without getting your hands dirty? Then make sure you visit this Web site's Multi-Functional Plastics Production Lab (M.F.P.P.L. for short).
Thanks to Marjorie Weiner of the National Plastics Center & Museum for providing plastics experiments.
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