Build a Thermos


Students design a thermos that will keep a drink warm OR cold for a long duration of time. 

Prior Knowledge:

Basic concepts of heat transfer; understanding of temperature relationships with material composition and speed of particle movement; engineering design process


  • Describe the difference in heat conductivity of different materials.
  • Understand how the speed of molecule movement relates to the temperature of an object.  
  • Evaluate different insulators and conductors. 
  • Engage students in thinking about the principles of engineering and using the engineering design process. 


On first first day of this project I'll talk about making coffee in the morning and wanting to keep it warm so I can drink it all morning long. I ask students which cup do they think I should use (Thermos, metal coffee cup, ceramic)? 

Get a poll from the class, then measure the temperatures.  It should be (from high to low) Thermos, metal coffee cup, ceramic. 

Ask them why they think this was so. Let them propose a few ideas then give them the design problem.

Design and build a thermos/cup that can keep 250 ml of water the warmest (or coldest) for 30 minutes.


  1. Must fit in your teacher’s hand.
  2. Must hold 250 mL of hot water.
  3. Be structurally sound (doesn't easily fall apart).
  4. No part of your container may be permanently altered as a result of the final test (your results must be repeatable without changing your container.)

You May:

  • Use a plastic/glass/ceramic cup as the core
  • Use any materials at home or from the store as long as they obey the “May NOT” section.

You May NOT:

  • Use a thermos/travel mug as the core
  • Use materials only accessible through your science lab classroom

Suggested materials list:

  • various colors of felt
  • various colors of construction paper
  • bubble wrap
  • mylar
  • various colors of foam
  • aluminum foil
  • plastic wrap

You must submit a detailed design to your teacher and have it approved before you begin building.

Grades/points are awarded based on:

  • Design
  • Effectiveness of design 
  • Flair/Creativity


After testing, students will complete a CER (claim, evidence, and response) to summarize their findings. The CER should address the following information:

Claim: what material(s) will work best

    -from STEM day and building thermos
    -generate a line graph to show temperature change over time
    -compare data results to a control in the experiment
    -compare data results to other designs in the class

Reasoning: explain why you were right/wrong

Download: Build_a_Thermos_Workbook_1.pdf

Teaching Strategies


StartSOLE is a simple inquiry-based approach that can be implemented in a single class period with minimal constraints and serves as an excellent addition or supplement to this lesson.  If you'd like to use one of these suggested questions to encourage students to dig deeper or help prepare them for this activity click on a link below to setup your StartSOLE lesson:

Return to top