How to Make a Homemade Thermos Bottle for a Science Fair Project

••• Sciencing

Thermos is the brand name for a particular type of thermal insulated flask. It basically consists of a watertight container placed inside another container with some type of insulating material placed between them. The inner container of a typical Thermos bottle is usually glass or plastic, and the outer container is usually metal. You can impress your science class by making your own flasks with plastic bottles and experimenting with different insulating materials to determine which one works the best.

  1. Cut the bottles

  2. ••• Sciencing

    Cut the tops off of three two-liter bottles with scissors to make them roughly the same height as the one-liter bottles. The larger bottles will serve as the outside of the insulated flask. Make sure the bottles are clean.

  3. Tape the bottles

  4. ••• Sciencing

    Apply masking tape around the perimeter of the cut edge to protect yourself from accidental injury.

  5. Glue the bottles

  6. ••• Sciencing

    Glue each one-liter bottle into the center of each two-liter bottle. Allow the glue to dry.

  7. Fill bottles with sand

  8. ••• Sciencing

    Fill the area between the two bottles with one of three insulating materials: fill one with sand; one with foam beads, such as those in a bean bag chair; and one with Polyfill insulation, which can be found at a craft store.

  9. Fill center bottle

  10. ••• Sciencing

    Fill each of the center bottles with the same hot liquid.

  11. Measure the temperature

  12. ••• Sciencing

    Measure the temperature of the liquid at regular increments for the next 2 hours. Record the measurements for interpretation at the end of the experiment.

  13. Record your results

  14. Evaluate the time versus temperature data for each bottle. Discuss which insulation material was more effective. Which material allowed the liquid to cool the fastest? Which retained the heat the longest? Discuss what this means regarding the insulating value (also known as the R-value) of the three materials.

    Things You'll Need

    • 3 one-liter soda bottles
    • 3 two-liter pop bottles
    • Masking tape
    • Small amount of all purpose glue
    • 3 insulating materials, such as sand, foam beads, and Polyfill insulation
    • Thermometer
    • Utility scissors



About the Author

Since 2003, Timothy Burns' writing has appeared in magazines, management and leadership papers. He has contributed to nationally published books and he leads the Word Weavers of West Michigan writers' group. Burns wrote "Forged in the Fire" in 2004, and has published numerous articles online. As a trained conference speaker, Burns speaks nationally on the art, science and inspiration of freelance writing.