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Shrinking Crafts
(from Lesson 5 - Reusing Materials)

In this lesson students will design and make their own craft items from polystyrene #6; they determine the percent of change in the dimensions and mass of the polystyrene #6.

Use of the book:
Teacher background on reusing materials: p.124.
Student background on reusing materials: p. 125-127.
Teacher notes on activity: p.136-139.
Student instructions for activity: p.140-141.
Data recording/Analysis questions: p.142-143.

Materials Needed:
Toaster oven (with tray), Spatula, Oven mitt, Polystyrene #6 (can purchase lids at restaurant supply store or collect enough from used packaging),
Permanent markers in different colors, Scissors, Calculators, Triple-beam balance, Rulers, Single-hole punch

p. 140-141 on overhead transparencies
p.142-143 back-to-back for participants
p.142 on an overhead transparency

Opening Strategy: p.138, (also the info on p.125-126 should be used as well)
What are some items that can be reused instead of thrown away?
Some famous examples:
· The Wright Brothers used bicycle parts to build the Kitty Hawk.
· Carl Tupper used polyethylene waste from Dupont to invent Tupperware.
· 1st Nordic Track built from parts from a junkyard.
· Rollerblades invented using old ski boots.

Procedure: p.140-141
Note: Skip the part about just making a rectangle, then making a craft later. Just do the craft right away, but make it in a rectangular shape.

1. Cut a rectangle shape out of polystyrene #6.
2. Measure the length, width and mass. Record in the data table p.142.
3. Color a design using permanent markers.
4. Bake in 350 degree toaster oven for 15-30 seconds. Observe while baking. Let cool about one minute.
5. Measure and record length, width and mass of shrunken PS#6.
6. Calculate the percent remaining:
shrunken size    X100
  original size
and the percent change in size: 100% - % remaining. Record in the data table.
7. Answer questions on p.142-143.
8. Discuss.

Polystyrene food containers
Polystyrene food containers
(courtesy of DCS)

Expanded Polystyerne Crafts
Expanded Polystyrene crafts (courtesy of Fast Shield)


  • Benefits of reusing garbage such as PS#6.
  • Would this work as a disposal method? Shrunken PS#6 takes up less space, but it’s now thicker/harder.
  • Most materials expand when heated, so why does PS#6 shrink? When it is manufactured, this plastic is stretched out into a film, then quickly cooled, which “freezes” the molecules of the polymer in their stretched-out configuration. When the plastic is heated again, the molecules within them are released from their “frozen” stretched-out configurations and return to their original dimensions. (p.139)
  • Extensions, Cross-Curricular Integration: p.148-139.
    • Make products to sell (ie. key chains, name tags) for a fund-raiser.
    • Try other shapes. (Try a cup.)
      Use as an activity for ratio/ proportion in math.
    • Use as an activity when studying polymers.
  • Related Activity: Treasures From Trash, p.128-135 – students make their own inventions or art from already-used materials that are generally considered to be trash.
  • The Garbage Gazette: p.144-145.
    • “ Earthships Take Off” – houses made with used materials
    • “ Don’t Dismiss Disposables” – reusable vs. disposable food-service items


Southwest Environmental Health Sciences Center
University of Arizona College of Pharmacy, Room 244
PO Box 210207, Tucson, AZ, USA 85721-0207

Funded by NIEHS grant # ES06694

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Last update: November 10, 2009
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