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Shrinking Chip Bags

Create miniature chip bags in your microwave

Shrinking Chip Bags

We can't get our hands on enough stuff to shrink. Faced with the problem of creating tiny chip bags (don't ask, some things are better left alone), we turned to Steve. "I don't know. Throw them in the microwave," was all he had to say. So we tossed a bag in the microwave and now we have this experiment. Is it scientific? Oh you bet your bag of salted potato chips that it's scientific.

Materials

  • Empty bag of SunChips (Big Grab size)
  • Microwave - Get an adult's permission
  • Adult supervision

Diving Ketchup

Diving Ketchup

Diving Ketchup

Diving Ketchup

Diving Ketchup

Diving Ketchup

Diving Ketchup

Diving Ketchup

Diving Ketchup

Diving Ketchup

  1. If you have an empty bag of SunChips lying around, awesome! You can use the empty bag. Skip to step 3.
  2. If you've got a bag full of SunChips, awesome! Eat the SunChips. You can share if you want, but it isn't necessary to complete the experiment.
  3. Take the empty bag of SunChips and place it inside of a microwave. STOP! Did you get an adult's permission? If you answered, "Yes," feel free to continue to the next step. If you answered, "No," we'd really feel better if you did.
  4. Close the microwave door and put it on high power for 5 seconds. Seriously, 5 seconds, and hit start.
  5. You'll see a tiny bit of sparks and hear a bit of noise from the bag, but don't be alarmed.
  6. When the 5 seconds of dust settles, you'll have a miniaturized SunChips bag!
  7. Wait for 30-60 seconds before taking the bag out of the microwave. It's hot!

How does it work?

Believe it or not, there is a scientific explanation behind the Shrinking Chip Bag. If you've visited our website in the past or follow Steve's appearances on TV, you know that we love polymers. That's exactly what comprises the SunChip bag. 
Polymers are long chains of molecules. Their natural state is similar to a knotted up string. When a bag of chips is made, these polymers are heated and stretched out to make the flat material used for chip bags. The high heat of this process locks the molecules in this "stretched out" state. When exposed to the heat of being microwaved, the material is able to release from the stretched state and return to its natural, bunched-up state.
 
But why do the shrinking polymers maintain the shape of the chip bag? This has to do with the other materials that are coating the polymer. Thin layers of aluminum, paint, and other materials line the outsides of the polymer and all of these layers are still bound together in the shape of the bag. So although the polymer chains bunch back into their natural shape, the overall bag shape is maintained.

Great Ideas!

Christine S.    -  December 14, 2011

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This user gave 5/5 stars


I wanted to thank you for the Sun Chips bag experiment. My students loved the experiment and really grasped what was happening with the polymers. Our math teacher loved the experiment, too, and had a great idea for using the shrunken bags (see attached)!

Thanks for all of the great experiment ideas. They are a great addition to my science lessons.

Pretty Cool

Shannyn Snyder    -  November 30, 2011

1 2 3 4 5
This user gave 5/5 stars


I am not sure how good this is for the life of my microwave, but we did the experiment 5 times and really got a kick out of it. We knew that plastic would likely shrink when heated, especially something so thin and made from a polymer, and the spark is from the metallic inner bag. The kids would have done this to a whole case of chips, so I'm glad we only had 5 snack bags around. We have a high powered microwave, so I tried the first bag at 4 seconds just in case, but you for sure need 5 seconds. We video taped our 5th bag which is pretty neat!

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