Melting Cups

This week our class completed an experiment in the kitchen.  As part of our inquiry into Changing Materials we decided to find out what happened when we put plastic cups and cup lids into a hot oven.

Step 1: Investigating our Material


The first thing we did was get better acquainted with our material of choice: plastic cups and cup lids.  We used our 5 senses to investigate them and shared our observations in a group discussion.

Step 2: Decorating our Cups and Lids

When the investigation was over, we decorated our cups and lids to make them more fun, and to help us tell whose was whose.

Step 3: Making Predictions

Next we tried to predict what would happen when our cups went into the oven.  We had a lot of interesting ideas.

  • The colour will change
  • It will turn black
  • The plastic will turn to fire
  • It will bake
  • It will get bigger
  • It will get smaller
  • It will get hot
  • It will turn hard
  • It will be different
  • It will grow higher
  • It will turn to a train
  • It will turn to a cheetah

Step 4: Bringing the Heat!

On Monday we visited the kitchen in our Colour Lines.  Each group carefully placed their object on the tray and we put it into the oven. While we watched, Mr. Bren recorded the observations we made.


Green Line

  • It’s jello, it looks like jello!
  • Mine is coming down
  • It’s falling
  • It’s broken
  • It’s breaking
  • It’s trying to get down

Yellow Line

  • It’s getting smaller
  • Wahhhh!
  • It’s getting small!
  • It’s so small!
  • They’re changing
  • That’s changing to be a small one
  • What’s happening?
  • It’s falling down

Blue Line

  • It’s brokening
  • Oh my!
  • Ahhhh!
  • Look at it!
  • It’s falling down smaller!
  • It’s flat!

Red Line

  • It’s turning to a new colour
  • It’s turning flat
  • Wow!

Final Observations and Reflections

When our cups came out of the oven and cooled down enough to touch, we examined them again and shared what we learned.


We learned that the oven had flattened the cup lids completely.  The new material was harder than before and had turned white in some places.  We saw that the lids had gotten smaller and noticed that they hadn’t turned black like some of us thought they would.

The cups changed in different ways, some of them turned flat and started to roll up, others just tipped over.  One looked like a pair of pants!  The cups were also harder to bend than before.

Everyone agreed that the hot oven had changed our cups and lids.  As a group we saw and felt that they were different than before.  We certainly couldn’t use them to drink out of anymore!

Coming Up

Term 1 is almost over.  We have begun work on our final project for Unit 2!


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About the author

Mr. Bren
Mr. Bren

Mr. Bren has Bachelor's Degrees in History from Concordia University in Montreal, Canada and Primary Education from Vancouver Island University in Nanaimo, Canada. He has worked at international schools in Mexico, Egypt and Korea. This is his second year as a Head Teacher in Peace & Unity.

In his spare time Mr. Bren likes rock climbing, scuba diving and playing sports.

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