You have probably seen or heard about this classic experiment before that involves dropping mentos into a bottle of coke and watching the soda erupt everywhere! This time we are going to add a little extra to this thrilling experiment with a homemade geyser tube. So let’s get started making this Mentos and Coke Volcano
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This has always been one of my favorite experiments to do! It is always fun to watch the reaction between the Mentos candy and the carbonated soda create a dazzling, bubbly, and sticky fountain into the sky…which is also why I highly recommend doing this science experiment outside!
Mentos and Coke Volcano
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- 2 Liter Bottle of Coke (or any kind of carbonated soda)
- Duct tape or electrical tape
- A toothpick
- 1 roll of Mentos (fruit or mint-flavored)
- Construction paper or card stock
- Safety glasses
- Scissors (optional)
How to make the soda and mentos experiment go higher with a geyser tube
- Roll a tube of Mentos up in construction paper or card stock. Tape the ends and middle to hold it in place and slide the Mentos tube out.
- Insert your new geyser tube carefully into the top of your soda bottle and secure it to the bottle with duct tape.
- Poke a toothpick into the lower part of the geyser tube just above the opening of the bottle.
- Place your soon to be coke and mentos volcano in a place that you are okay with getting sticky and messy (this is the part I prefer to do outside).
- Make sure your toothpick is all the way through the center of the geyser tube to keep the Mentos from falling and put on safety goggles.
- Gently and slowly drop about 5 Mentos into the top of your geyser tube.
- Pull the toothpick out of the paper tube to release the Mentos into the bottle and quickly get out of the way to enjoy watching the eruption!
Step 1: Create your geyser tube
Before we get started doing the most exciting eruption part of this experiment, we need to make the geyser tube. I promise taking the extra time to make this will be well worth it and make the Coke and Mentos volcano go higher!
To make this geyser tube you will need to grab a piece of construction paper or card stock. The roll of Mentos is the perfect sized diameter to roll your paper around to make a geyser tube. Begin rolling your paper longways with the roll of Mentos inside to help shape your paper into the tube that you need.
Once you have rolled the paper up as tightly as you can around the Mentos, grab some electrical tape or duct tape and wrap both ends of the geyser tube to secure it in place. You might also want to put a piece of tape over the seam of the paper in the middle of the tube to make sure it doesn’t unroll.
When you are done taping the middle and ends of the tube and it feels nice and secure, go ahead and tip the tube up and slide the roll of mentos out of the tube.
Step 2: Connect your geyser tube to the top of the soda bottle
Now that you have created your magical geyser tube, go ahead and attach it to the opening at the top of the 2-liter bottle of soda. Before doing this remember to take the cap off the bottle.
Depending on how tightly your geyser tube was rolled up, you should be able to insert the end of the tube into the inside opening of the bottle. If your geyser tube was rolled a little bit loosely and has a digger diameter, then you can slide it over the outside of the opening of the bottle instead.
Once you have either inserted the tube on the inside of the opening of the bottle or slid the tube over the opening, go ahead and securely attach the tube to the bottle with electrical tape or duct tape. I personally prefer to use duct tape since it seems to stick better and stay on better when it gets wet in the eruption.
You do want to wrap a couple of layers of tape tightly around the connection to get the best seal possible. The better your connection is on the geyser tube to the bottle, the higher your eruption will go.
Step 3: Slide a toothpick through the geyser tube
This part can be a little bit tricky depending on how thick the construction paper or card stock for your geyser tube is. If you are using standard construction paper, then you should be able to poke your toothpick through the tube and the tape on the outside of the tube fairly easily.
If you are using thicker card stock paper, you may need to use a paperclip or even a small needle to poke a hole through the tube first, and then insert the toothpick through the hole in the tube.
Whatever method you decide to use, make sure to put the toothpick in near the bottom of the geyser tube and just above where the tube connects into the bottle.
Look through the tube and double-check that the toothpick is in going through the center of the tube and sticking out of both sides. It is important to make sure the toothpick is in a spot to keep the Mentos from falling into the soda bottle.
The toothpick will act as the firing pin for the Mentos and soda eruption, so you want to make sure it is in the right spot! You do not want the eruption to fire prematurely and make a mess…trust me I have learned this part from experience!
Step 4: Move to a place away from anything you don’t want to get messy
We are almost ready for the grand finale of this favorite experiment, but before you get too excited and drop those Mentos into the soda bottle you might want to take this experiment outside!
One thing that I have learned in doing this Mentos and Coke Volcano is that no two eruptions are alike. Sometimes a few Mentos can fall into the bottle and some can get stuck in the tube and create a funnel that shoots sticky soda spray 10 or more feet high (I learned this the hard way and gave my house a sticky diet coke bath)!
Other times, when all goes as planned, this geyser tube should create a steady fountain of soda that shoots about 3-4 feet high above the bottle. Bottom line, do this in an area that is okay to get messy and be prepared for anything!
Step 5: Make sure the toothpick (firing pin) is in and ready to hold the Mentos
Now that you are outside, or in a good area to start your reaction, double-check that your toothpick is inserted all the way through the geyser tube. It should be near the bottom of the tube and going through the center to keep the Mentos from falling into the soda pop below.
Since the next step is when our volcano begins to erupt, I highly recommend putting your safety goggles on now before it’s too late!
Step 6: Load Mentos into the geyser tube
Very gently and slowly drop about 5 Mentos into the top of your geyser tube. Mint or fruit-flavored Mentos will work for this reaction, but I prefer to use the mint ones just because I love to save the fruit ones for a little tasty treat!
The toothpick in the bottom of the tube should do its job to stop the candies from falling into the soda, but just be on guard in case a Mento finds it’s way past the toothpick and into the soda. If this happens, your eruption will start prematurely and you will want to get out of the way quickly!
Step 7: Pull the toothpick out of the geyser tube and watch the reaction
As you quickly pull the toothpick out from the geyser tube it will allow the Mentos to drop into the soda and you will almost instantly see your Coke and Mentos Volcano erupt into a brilliant brown fountain!
Hopefully, by this point, you have quickly moved out of the way to a safe and dry viewing distance, or you might get sprayed by some sticky volcanic soda!
The good news is that as long as you don’t mind a little mint flavor in your drink, or a flat soda…then you can pour the remaining soda into a glass and enjoy a little post-experiment refreshment too!
Coke and Mentos Explained:
This Coke and Mentos volcano happens thanks to the reaction between the gelatin and gum molecules in the Mentos and the carbonation in the soda pop. Carbonated soda beverages contain carbon dioxide that is dissolved in the soda and attached to water molecules.
The gelatin and the gum in the Mentos help to break apart the water and carbon molecules that are stuck together in the soda. Another factor that helps the eruption happen with even more force is the fact that the Mentos are denser than the liquid soda and they sink to the bottom.
Mentos also have tons of tiny little microscopic pits on their surface which are a double whammy for creating a great reaction. The tiny little holes on the surface of the Mentos allows a spot for carbon dioxide bubbles to form rapidly, which leads to the eruption.
When the carbon dioxide bubbles form on the microscopic holes in the Mentos, the bubbles rise and push all the soda up and out of the geyser tube with them and creates the Coke and Mentos Volcano that we all love!
Do you have to use Coke to create the Mentos eruption?
Even though this experiment is often referred to as the “Coke and Mentos experiment,” you can actually use any kind of carbonated soda with Mentos to get this stunning reaction. It is true though that some flavors of soda are known to produce better reactions than others.
This is mainly because some sodas have more carbon dioxide in them than others. The carbon dioxide is what creates all the bubbles and creates the pressure to make the fountain of soda.
From my experience, Diet Coke is actually the best option for this Mentos and Coke Volcano for a couple of reasons.
Diet Coca-Cola has a lot of carbonation (carbon dioxide) so it makes the reaction great! There is also less sugar in Diet Coke than other sodas, so it doesn’t get quite as sticky and messy to clean up in the end.
Do Fruit Mentos work with Coke?
Yes! You can use Fruit Mentos or Mint Mentos to create the Mentos and Coke volcano. It does seem like the Mint Mentos react a little more intense with the soda and create a slightly higher fountain of soda though.
I personally prefer to use the Mint Mentos for this experiment to get the biggest and best eruption as possible…and to save the tasty Fruit Mentos for myself since they taste way better than the Mint Mentos!