Spot the Polymer

Summary: Students are introduced to the idea of a polymer. Students look at examples of polymers and apply their knowledge to a "people" polymer.

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Estimated Time: 15 minutes

Materials Needed:

• Examples of polymers, such as:
  • paper
  • CD
  • egg carton
  • plastic bag
  • plastic soda bottle
  • paper napkin
  • disposable plate (plastic, styrofoam, or paper)
  • a piece of wood
• 1 paper clip chain
• 1 plastic cup
• 1 plastic bag

Safety Notes: We do not recommend ingesting any materials. Plastic bags should stay away from mouths as they can cause choking.

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Part One - What Is A Polymer?:

Procedure:

• Place all of the polymers on a table for students to look at. Discuss how the objects are and how they are different.
• Explain that all of the objects are made of polymers. A polymer is made of made of many (50+) repeating units so small that we can’t see them with our unaided eyes. The word polymer means "many units." A polymer is like a chain of paper clips, where one paper clip is a "mer," or unit. Several paper clips linked together represent the polymer.
  • Use the paper clip chain to "show" a polymer.
  • Are polymers small or big to us? Small because we can't even see them with just our eyes. What about in the world of atoms (if we could go way down inside of things and be the size of things that make them up - like Ms. Frizzle in the Magic School Bus)? Are they big or small? They are very big and long there.
• Ask students if they can find examples of polymers in the classroom, or on their clothes or shoes.
  • Are all polymers plastic? No. For example paper, wood, and tortoise shells are all polymers.
  • What are some things that are not polymers? Metal, any of the elements, and salt are some examples.
  • For middle/high school: Is a cup of water a polymer? No. There are a bunch of water molecules there but they are not all chemically bonded together. So a cup of water is like a cup of paper clips that are all unconnected.
• Polymers are important in part because they can act in so many different ways. Scientists can make polymers that have different properties. Some hold music, like a CD, and some hold liquids, like a soda bottle. Show the students a plastic cup and plastic bag side by side.
  • If I drop this cup, what will happen?
  • What will happen if I drop this bag?
  • Which is easier to tear – the cup or the bag?
  • I can drink out of the cup, but do you think it would be a good idea to try to drink out of the bag?
  • Would you rather carry your groceries in the bag or the cup?

Part Two - Making a Class Polymer:

• Ask for six student volunteers, and have them come to the front of the class.
• Ask the students to form a polymer.
  • Students should be connected in some way. Most likely students will hold hands.
  • Carefully try to move around. It is fairly easy for our polymer to move around. Is our polymer more like the plastic bag or more like the cup? [the bag]
  • How can we make our polymer more like the cup? How can we make it harder for them to move? The arms are the bond that our polymer has now. It’s kind of floppy. How can we make it stronger?
  • Help students brainstorm. Ideas include: liking at the elbows, holding arms tight, and linking at the feet in addition to the arms. Have the students in the polymer enact each suggestion. Now have the students try to move. It is very hard for our polymer to move like this because we made it stiffer like the cup.
    

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Teaching Tips:

• Depending on age, students may dislike holding hands.
• Modify questioning to fit your students.
• For a different introduction try giving students examples and non-examples of polymers and letting them group the objects how they see fit before explaining about polymers.
• A more detailed version of this activity was distributed in our newsletter. Accompanying this version of the activity is an interview with a scientist who works on polymers. You can view this online.