Mentos Soda Science Experiment – Create Your Own Geyser
The Mentos Soda Science Experiment needs almost no introduction since Steve Spangler’s YouTube video went viral in 2005. It was first showcased on The Late Show with David Letterman in 1999, as well as being the subject of a MythBusters investigation in 2006. This experiment is a fantastic experiment to perform with adults and children alike.
Everyone will want to get involved and try it for themselves!
Needless to say, a large amount of soda escaping rapidly from the nozzle of a plastic bottle will go in any number of directions. For the sake of your home decor, this is one of those experiments that must be performed outdoors.
If the weather isn’t suitable for outside activities, then why not have a try our Fluorescence experiment. It’s great fun!
Perform the Mentos Soda experiment with the soda bottles on a solid surface like an outdoor table or bench and make sure that the area you are going to use is not overhung by bushes or low trees. The geyser can reach a height of 30 feet in the right conditions.
It’s also a good idea to cover the table with a throwaway covering or a sheet, as a large amount of the soda will land on the table on the way down.
Equipment Required To Make Your Geyser
- 2 Liter bottles of Soda (Diet Coke)
- Tubes of Mentos – 10 Mentos per bottle
- Mentos Geyser Tube
- Construction or colored paper for making your own Mentos tube
- Electrical or Duct tape
- Safety Goggles
There are a number of inexpensive plastic Mentos Soda Geyser tubes that does the job perfectly. Using one will save you the task of creating your own Mentos delivery tube and it will send the Mentos into the soda, without any getting stuck in the tube or being dropped along the way.
The experiment works well with both regular or diet soda but my advice would be to use Diet Coke, where possible.
Research has shown, that the resulting geyser is larger in drinks that contain Aspartame and Potassium Benzoate as a preservative, like Diet Coke. Also, try to use a bottle of soda that has been chilled in the refrigerator.
The carbon dioxide in the bottle is more readily absorbed into the liquid if it is cold. Diet drinks also contain less sugar, so cleaning up afterward is a less sticky affair!!
If you don’t have a Mentos Geyser Tube already, you can also create one from construction paper, as shown in the following steps. Children love making the paper tubes and it adds a great craft element to the experiment.
They are quick and easy to create so if you have the time, it is worth making a few in advance.
Making A Geyser Tube
A critical component of this experiment is the tube that allows the delivery of the Mentos into the Soda. A smooth and fast delivery is essential to showcase your geyser to it’s a full potential.
- Take a tube of the Mentos mints and wrap the construction paper around it. Not too tightly now, as we need to ensure the Mentos will not get stuck in delivery.
- Take a little tape and wrap it around the bottom and top of the paper. Keeping the Mentos tube in place will help keep the paper tube from and easier to tape. You can also fix a length of tape along the entire seam of the paper for extra stability.
- Remove the Mentos candy tube from paper tube via one end.
- Carefully insert the toothpick through the paper tube approximately 5 cm above one of the taped ends. The toothpick will act as the release trigger, allowing the Mentos to fall into the Soda smoothly.
Let’s Take A Moment To Talk Safety!
The geyser experiment is not dangerous by any means, but it is good practice and common sense to protect the eyes of children and adults who are actually going to pull the pin and deliver the Mentos into the bottle.
Create Your Own Spectacular Soda Geyser
Once your Mentos Tube is ready, It’s time to go right ahead and create a spectacular geyser of your own.
- With your safety goggles in place, put the first bottle of Soda on a steady outside surface, preferably a table.
- Unscrew the top and insert the end of the Mentos tube with the toothpick into the bottle. Make sure that the end is inserted approximately 2 to 3 cm in o the neck.
- Tape the neck of the bottle with the tube inserted, so that the tube remains vertical and stable without your having to hold the tube in place. This step can be seen in the tube construction video above.
- Ensure that the toothpick is centered in the tube, to stop the Mentos dropping straight into the bottle.
- Fill the tube with 10 Mentos Mints
- Now for the moment, everyone has been waiting for! When everyone watching is paying attention, pull the toothpick out of the tube, allowing the Mentos to drop into the bottle. The reaction will be instantaneous so as soon as you pull the pin take a couple of steps backward, otherwise I’m afraid you will end up in a Soda shower.
Take a moment to watch Steve Spangler’s – Mentos Geyser – Viral Video
Mentos Soda Experiment Facts – Can we Explain it?
I think you will agree that this experiment is truly spectacular and one of those reactions that you want to see time and time again. The explosive nature of the reaction always leaves people wondering how and why!
Most people assume that there is some sort of chemical reaction between the Diet Coke and the Mentos Mint.
It’s a natural assumption to make given the extreme nature of the reaction but in this case, it is actually a physical reaction, referred to a Nucleation!
What is Nucleation?
In the wonderful world of nature, liquid molecules want to be next to each other, It’s a fact. When you drop something into the soda, it disrupts that natural attraction of liquid molecules with each other The object that causes the disruption then becomes a growth site for Carbon Dioxide bubbles. The Carbon Dioxide gas is already dissolved into the Soda during the manufacturing carbonation process. These growth sites are referred to as nucleation sites.
Microscopic scratches on the inside of the Soda bottle, also act as nucleation sites. This is visible as bubbles accumulating on the side of the bottle, once the cap is removed.
You can also see this happening if you put your finger into a glass of carbonated water. The tiny lines and ridges that go to make your fingerprints, also act as nucleation sites. Give it a try yourself!
So what is so special about Mentos Mints?… I hear you ask.
Well, it all comes down to the manufacturing process of the humble Mentos Mint!
Mentos mints are covered with a coating that is actually very rough. They may look shiny and smooth to the naked eye but viewing the surface under a microscope reveals a surface that is not unlike the moon.
All those millions of microscopic bumps, nooks, and crannies create a large surface area for the carbon dioxide bubbles to form. In fact, there are so many bubbles forming as the heavy Mentos drops through the Soda that they cannot be contained within the bottle. The bubbles turn into a foam as they continue to multiply forcing any remaining liquid out of the bottleneck.
Mentos Geyser Science Fair Project
As you’ve seen from our experiment, it is spectacular and actually rather simple to explain.
For older children, It’s also a lot of fun to turn this simple experiment into a science project, introducing a number of variables and challenges for them to investigate and to record their findings.
Ask them to think about what could change or impact the outcome of the reaction.
Some examples to think about.
- Which type of Soda creates the highest geyser?
- Does the temperature of the Soda have any impact?
- Do Fruit Mentos also cause the same reaction?
- What is the ideal number of Mentos for this experiment?
As with all our experiments, the emphasis is on enjoyment, having fun and spending time together!
Time together is precious, so take the time to do this experiment with others and let everyone have a go!
I would really like to hear any feedback and also to read about your own Soda Geyser Science Project.
Thank you for reading, your comments are very welcome!
Enjoy our other experiments