Bubble Battles

Bubble Battles
  • Age: 8+
  • Time: 30
  • (Setup: 10 min, Activity: 15 min, Cleanup: 5 min)
  • Materials: $19

Prepare for battle. A Bubble Battle. In this mission you’ll find out how hard water and soft water can cause soap and detergent to react in the same—or different— way, depending on the combination. You’ll do this by learning about zeolites and playing with bubbles!

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  • what you need

    Safety Note: Grownups, supervise children so they do not accidentally inhale powdered detergent. If detergent comes into contact with eyes, flush with plenty of water.


    • 1 cup distilled water, found in the bottled water section
    • ¼ tsp. Epsom salt
    • ¾ tsp. powdered laundry detergent containing aluminosilicates (like Tide)
    • ¾ tsp. of bar soap without EDTA, grated (like Ivory)


    • 4 small jars with lids, like baby food jars
    • Measuring cup
    • Measuring spoons
    • Marker
    • Masking tape

    Note: The printable PDF for this experiment includes a data sheet for marking observations.

  • What To Do
    1. Using a marker and labeling tape, label your jars. Two will start with “S” for ‘soft' water and two will start with “H” for ‘hard’ water. We call distilled water ‘soft’ because it doesn’t have any minerals in it and hard water ‘hard’ because it’s loaded with minerals, like salt. Then in each pair, label one with “S” for ‘soap’ and one with “D” for ‘detergent.' Your jars will be labeled like this: “SS”, “SD”, “HS” and “HD.”
    2. Soft Water Bubble Battle: Add ¼ cup distilled water to both jars starting with the label “S.” Then add ¼ tsp. of detergent to one jar and ¼ tsp. of soap to the other. Close the jars and give 5 strong shakes to them at the same time.  Which makes more bubbles, soap or detergent? Write down your observations.
    3. Hard Water Bubble Battle: First, mix ½ cup of distilled water with ¼ tsp. Epsom salt to make hard water, then pour your mixture into the both jars starting with the label “H.”  Repeat Step 2 using the hard water. Which makes more bubbles, soap or detergent? Write down your observations.
    4. Bonus Bubble Battle: Repeat the same experiment using your tap water. If you compare the bubbles to your previous results, do you think that the mineral content of your tap water is closer to hard or soft water?

    Cleanup: All soaps and liquids can be thrown away in the sink. Recycle or reuse glass jars for another purpose.

  • What's Happening?

    You may have noticed that the detergent created more bubbles than soap in hard water. When water is hard, the minerals in the water prevent soap from bubbling, creating soap scum.  Since we don’t want soap scum on our clothes, we use detergent instead, which is combination of soap and a type of material called sodium zeolite A.  When you use detergent in hard water, the zeolites trap the minerals that cause soap scum.  This helps your clothes get clean even if your tap water is hard.

  • So What?
    Diagram of a square grid of alternating red, pink, and yellow atoms. There are regularly spaced holes in the grid where there are no atoms.

    Image credit: Xueyi Zhang/Penn State

    SO WHAT?

    Zeolites are materials that have empty spaces in their molecular structure that can trap other molecules. This property makes them versatile materials that can be used to clean and collect molecules. Zeolites can remove toxic chemicals in the atmosphere. They can be used to combat excess carbon emissions from power plants by trapping some of the carbon dioxide that is generated when burning coal. Zeolites were also used to clean up radioactive molecules in the water that was polluted in the 2011 Fukushima nuclear accident.

    Scientists can design better zeolites for different applications. A new use of zeolites is in collecting lithium from sea water. Lithium is an essential component in the batteries we use to power our technology every day, from cars to cell phones. The demand for lithium is high, so zeolites create an alternative way to collect lithium.

  • Scientists In Action
    Scientists In Action

    Scientists like Chrislynn Suah and David Vaughan know that their research can make the world a better place. From laundry detergent to batteries, how are new materials helping us protect our environment?