The Mentos Explosion

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Science-U DIY Experiment Series Asks: What is a Physical Reaction?

The "How To" From Science-U


  • 2-liter of soda (Diet Coke works best)
  • Roll of mint mentos (original, not fruity)
  • Outside area that can handle a soda mess!


  1. Place a 2-liter upright, with plenty of space around.
  2. Remove the mentos from the wrappings. You will use one whole pack for each 2-liter bottle, and will need to drop each pack into the bottle all at once. You can use a rolled paper tube or other funnel device to help do this quickly! Ours were commercially available “Geyser Tubes” purchased online.
  3. Working as fast as possible, open your soda bottle, and drop the whole pack of mentos into it.
  4. Stand back and watch the soda explosion!
  5. For added scientific fun, experiment and investigate what works best. Is there a difference between diet and regular soda? Number of Mentos? Room temperature vs. chilled?  What about flavors?

The Science Behind It

Soda has Carbon Dioxide (CO2 )pumped at high pressure. Water molecules in soda  normally form a “mesh” of surface tension around the liquid, keeping it relatively stable. Mentos disrupt that surface tension, while simultaneously providing a rough surface ideal for CO2 bubbles to form and fizzle (the fruity ones are too smooth for this). Once all those CO2 bubbles have formed, there’s only one way for them to escape—up and out, very quickly!

Source: Soda Explosion Activity