The Mentos Explosion

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DIY Experiment Series Asks: What is a physical reaction?

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The "How To" From Science-U

Ingredients:

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

Instructions: Campers Watch Mentos Explosion

  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 changing different variables.

For educators and parents - How to guide young learners in science:

  • Inquiry-based learning (IBL) is a teaching approach that is fundamental for the development of higher order thinking skills (summarizing, analyzing, evaluating, creating). It puts the student in the driver's seat and promotes learning through engaging student-based investigations, following the same process used by scientists.
  • IBL begins by posing a question, problem, or scenario rather than simply presenting facts or a standard method to solve a problem. The learner is actively engaged and investigates concepts to reach authentic meaning.
  • The IBL process can vary, however the basics are as follows:

1. The student creates a testable question of their own.

2. The student obtains supporting evidence to answer the question by making observations, doing research, collecting data through an experiment, changing variables from a previous experiment, etc.

3. The student explains the evidence collected.

4. The student creates a claim (explanation) and justifies it using evidence form the investigation.

5. The student creates predictions for future investigations.

  • Recording information during the IBL process is also important to promote science literacy. The following chart is a helpful tool to guide students through the process.

Guided inquiry map

Questions to ask:

  • Is there a difference between diet and regular soda? Number of Mentos? Room temperature vs. chilled?  What about flavors?
  • What combination of soda and mentos makes the biggest geyser? 20oz soda and 5 mentos? 2L soda and 10 mentos? Try taking a video of it against an outside wall and measure how high it goes!

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!

Resources:

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