Diet Coke and Mentos Eruption

Love fizzing and exploding science experiments? YES!! Well, here’s another one the kids are sure to love! All you need is a pack of Mentos candy and diet coke. You might think there’s a chemical reaction happening, but this Mentos and soda experiment is a great example of a physical reaction.

DIET COKE AND MENTOS EXPERIMENT

SCIENCE EXPERIMENTS FOR KIDS

We love fizzing experiments and have been exploring science for kindergarten, preschool, and early elementary for over 8 years. Make sure to check out our collection of simple science experiments for kids.

Our science experiments are designed with you, the parent or teacher, in mind! Easy to set up, and quick to do, most activities will take only 15 to 30 minutes to complete and are tons of fun! Plus, our supplies lists usually contain only free or cheap materials you can source from home!

Grab a packet of Mentos and some diet coke, and find out what happens when you mix them! Do this activity outside to make clean-up a breeze. Just make sure to put it on a level surface, so the bottle doesn’t tip over.

Also check out these other fun variations of this Mentos experiment that are great for younger kids and a bit less mess!

LOOK: Mentos and Coke Experiment

COKE AND MENTOS SCIENCE

Is coke and Mentos a chemical reaction? With all the fizzing and foaming going on it looks like there must be a chemical reaction happening between the Mentos and diet coke, like our elephant toothpaste or baking soda and vinegar volcano.

However, you might be surprised to know this experiment is an example of a physical change. Read on to find out why Mentos makes coke explode if there is no Mentos and coke chemical reaction.

Inside the coke or soda, there is dissolved carbon dioxide gas which forms a bond with the water, making the soda taste fizzy when you drink it. This is called a carbonated beverage. Usually, you can find these gas bubbles coming out of the soda and creating a bit of foam in a glass.

However, much of the gas is trapped on the surface of the soda, waiting to get out! They are held there by a scientific concept called surface tension. Once the mentos are added, the gas bonds break down more quickly due to the rough surface of the candy.

Adding Mentos speeds up this process because more bubbles form on the Mentos’s surface than on the bottle’s side and push the liquid up. This is an example of a change of state of matter; the carbon dioxide dissolved in the diet coke moves to a gaseous state.

Did you know that you can try this experiment with other types of candies and even pennies? That’s because it’s a physical change instead of a chemical one! Go ahead and experiment!

HOW TO APPLY THE SCIENTIFIC METHOD

Mentos candy are relatively dense and sink quickly, causing a powerful, fast eruption; EYE PROTECTION is recommended if you are standing close!

You can extend this Mentos and coke experiment below with additional suggestions. Older kiddos will benefit from learning about and incorporating the scientific method!

If you want to set up an experiment with several trials, pick one thing to change, such as the type of soda! Don’t change everything! You need to change the independent variable and measure the dependent variable.

You can also get kids started by writing down their hypotheses before diving into the experiment. What do they think will happen when the Mentos is added?

After performing the experiment, kids can conclude what happened and how it matched their initial hypotheses. You can always change a hypothesis upon testing your theory!

CLICK HERE TO GET YOUR PRINTABLE MENTOS AND DIET COKE PROJECT!

MENTOS AND DIET COKE ERUPTION

SUPPLIES:

2 liter Diet Coke
Mentos candy
Index cards
Tape
String

INSTRUCTIONS:

STEP 1: Roll up an index card into a tube and tape it together. The tube needs to be large enough to hold the Mentos and still allow them to fall out easily.

STEP 2: Tape the tube to the top of your bottle, but only tape on one side. An index card needs to be able to fit underneath the tube from one side.

STEP 3: Place the other index card under your tube and attach your string to it with tape.

STEP 4: Drop the Mentos into the tube.

STEP 5: Now back away with the string in hand. Pull the string, which will also pull out the index card, allowing the candy to fall in.

NOTE: If you can, set up a measuring tape in the background to help record the height of the eruption. Or place a piece of tape at a certain height on a wall or garage door to get an approximate idea of the height of your eruptions!

If you’re recording the eruption, use the slow mode function to capture the peak height more easily. You’ll be able to pause and check out the fountain height.

Watch the excitement from a safe, and clean distance!

EXPAND THE EXPERIMENT, EXPAND THE FUN!

What about crushed Mentos? Change the size of the Mentos by breaking them into small pieces to test whether that changes the amount of foam produced.

What about soda flavors? Compare different types of soda while adding the same amount of Mentos to each. Which produces the most foam, diet coke or original coke? How about Orange, Root Beer, or Sprite? Does club soda or seltzer erupt?

What about temperature? Does ice-cold Diet Coke work better than room-temperature Diet Coke?

What about mint flavors? Do Mentos mints or Fruit Mentos work better?

What about alternative items? What can you try instead of Mentos candy? Will it produce the same results or a similar height of eruptions? Other options could include pennies, rock salt, or different size candy!

MENTOS AND COKE SCIENCE FAIR PROJECT

Science projects are an excellent tool for older kiddos to show what they know about science! Plus, they can be used in all sorts of environments including classrooms, homeschool, and groups.

Kids can take everything they have learned about using the scientific method, stating a hypothesis, creating variables, and analyzing and presenting data.

Want to turn this Diet Coke and Mentos rocket into a cool science project? Check out these helpful resources below.

MORE FUN SCIENCE EXPERIMENTS TO TRY

Click on the link or on the image below for more fun and hands-on science experiments for kids.