You Will Need:
- A parent’s help
- 1 Bottle of diet coke
- 1 Nail or small hand drill
- String
- Scissors
- Outside space
- Needle
Drill a small hole through the lid of the bottle using a hand drill or a nail. Pour out the first 5cm of Diet Coke for extra working room.
Use the needle to thread the string through four Mentos, leaving a 10cm length of sting trailing off the Mentos Bundle.
Thread the trailing string length through the bottle cap. Tie a knot on the end of the string behind the mentos so they can’t fall of the string.
Pull the string tight, so that the Mentos bundle is up against the lid. Don’t let go of this string yet!
Carefully screw the lid onto the bottle, making sure that the Mentos do not touch the Diet Coke.
Find an area that can get wet. When you’re ready, release the string!
School science visits since 2004!
– Curriculum-linked & award-winning incursions.
– Over 40 primary & high school programs to choose from.
– Designed by experienced educators.
– Over 2 million students reached.
– Face to face incursions & online programs available.
– Early learning centre visits too!
Online courses for teachers & parents
– Help students learn how science really works
Why Does This Happen:
We are often asked how this experiment works when we visit schools.
Many students have come to believe that it is a chemical reaction between the Mentos carbonates and the Diet Coke acids that makes the fountain work… however, it turns out that research findings have turned up a quite different explanation; the reaction is largely physical, not chemical.
Diet Coke has a massive amount of dissolved carbon dioxide in the liquid. When you open a Diet Coke bottle, the gas is released instantly, i.e. bubbles form. How does this happen? The solution is actually super-saturated with gas – the gas would escape the liquid if it wasn’t for the high pressure within the unopened bottle. Opening the bottle allows the gas to be released.
Bubbles can also form on tiny points on the surface of a container, known as nucleation points, or site. When you pour a carbonated drink into a glass, the very fine scratches on the glass cause the bubbles to be formed on the tiny nucleation points along the scratches of the glass.
A Mentos has many, many fine scratches on the surface; a perfect place for bubbles form. Dropping a Mentos into Diet Coke allows the dissolved gas within the liquid to come out of the solution extremely quickly, courtesy of the many nucleation points on the Mentos surface.
Variables to test
- Try different numbers of Mentos… how high can you make it go?
- Try different soda drinks. Which carbonated drink make the Mentos eruption go higher?
- What happens if you use cold vs. room temperature soda drinks?
- Does using different flavours of Mentos produce any measurable difference in how high the eruption is?
From colour changes to slimy science, we’ve got your kitchen chemistry covered!
Get in touch with FizzicsEd to find out how we can work with your class.
Chemistry Show
Years 3 to 6
Maximum 60 students
Science Show (NSW & VIC)
60 minutes
Online Class Available
Chemistry Show
Years 3 to 6
Maximum 60 students
Science Show (NSW & VIC)
60 minutes
Online Class Available
STEM Full Day Accelerator - Primary
Designed from real classroom experiences, this modular day helps you create consistently effective science learning that directly address the new curriculum with easily accessible and cost-effective materials.
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