Keep a Cube (Student Instruction)

Students design a container to keep an ice cube from melting for as long as possible.




  • 1 cardboard box, less than 1 cubic foot
  • Waxed paper
  • Masking tape
  • Newspaper
  • Aluminum foil
  • Rubber bands
  • Ice cubes


  1. Identify the Problem
    • The most critical step of any engineering challenge is to understand the problem you are trying to solve.
    • The problem you are trying to solve is heat transfer. This is when the heat in the air of the room is transferred to the ice cube, causing it to melt.
    • Insulation is any material that reduces heat transfer. Using insulation in the walls of a container allow us to keep hot things hot and cold things cold.
  2. Collect Materials
    • Start collecting materials for your container. You will need two ice cubes later, after you are done building.
    • Suggested container materials: a cardboard box or shoebox, masking tape, paper, aluminum foil, rubber bands.
    • Don’t have all of these items? Look around and see if there are other materials you can use that would make good insulators.
      • Don’t have a cardboard box? Can you make one out of an old pizza or cereal box or use a plastic take out container?
      • Don’t have aluminum foil? What about using old t-shirts or rags instead?
  3. Brainstorm Designs
    • Review the challenge and the problem you are trying to solve.
    • Look at your materials. Do you think the materials you collected are good insulators? Why or why not?
    • Record the materials you are using and whether you think they will make good insulators.
  4. Build It
    • Start building! If possible, take pictures of the materials as you build. Maybe one at the beginning, one during the process, and one at the end.
    • When you are finished building, make a prediction. How much will the ice cube will melt in your container?
    • Record your prediction.
  5. Test It
    • To test your design, you will need two ice cubes – one for your container and one as the
    • When you are ready, place one ice cube in your container. And place the second ice cube in a bowl outside of your container.
    • If possible, take a picture of the two ice cubes at the beginning to remind yourself of what they look like.
    • Set a timer for 90 minutes (or use a clock and record the start time).
  6. Share Results
    • After 90 minutes, look at both ice cubes and report the results.
    • What do the two ice cubes look like after 90 minutes? If possible, take a picture.
    • Did the cube in the container melt as much as you predicted?
    • Did the cube in the container melt as much as the control?
    • Examine your container. Are there any places where air or heat is getting into their container?
    • Are there any changes you want to make to your container?
    • Other materials you want to try?
  7. it’s time to redesign your container and try again!

Activity courtesy PBS Kids.