1. Mentos and Diet Coke geyser
S.T.E.M. Challenge
Chemical & Physical Reaction

2. I wonder what will happen if…
Several people have wondered what would happen if you combine two popular treats…
Candy
Soda

3. So… What happens when you mix candy and soda?
Who would have ever guessed that dropping MENTOS chewy mints into a bottle of soda would produce a volcanic reaction!
original-mentos-diet-coke-geyser

4. What causes the huge reaction?
The reaction- a giant eruption of soda- is as mysterious as it is sensational.
Some scientists believe the reaction is chemical while others believe that it is physical.
But really… the reaction is just the same as a volcano erupting or a geyser!

5. Chemical reaction…
When you drop the Mint Mentos candy into the Diet Coke it starts to foam and erupt.
Ingredients contained in the Mint Mentos
(Gelatin, gum acacia)
Ingredients contained in the Diet Coke-
(Carbon Dioxide gas CO2, benzoate, caffeine, aspartame, potassium)
So… when the ingredients from the two are combined together it goes KABOOM due to the invisible carbon dioxide gas CO2 (or bubbles) in the soda that cannot expand like gases like to do in the bottle!

6. Physical Reaction…
When you drop the Mint Mentos candy into the Diet Coke a physical reaction occurs because of the surface of the Mentos.
Nucleation on the surface of the candy (tiny little holes) allows the carbon dioxide gas (bubbles)in the soda to form very fast and grow rapidly.
This causes the eruption of foam!
So… because the candy has holes like a golf ball, the bubbles in the soda rise to the top of the bottle and a bunch of gas bubbles are made which causes the KABOOM eruption!

7. Why do mentos candies and diet coke Make the best reaction?
Diet soda has more carbonation CO2
Diet coke has different ingredients
Artificial sweetener makes a better reaction
Less sticky to clean up 
Better reaction with newer bottles of soda, the older the bottle the less carbon dioxide gas (less bubbles, flat soda)
Better reaction with room temperature soda, not cold
Mentos
Nucleation (tiny holes on the surface)
40 layers of microscopic sugar all with holes
Carbon dioxide gas bubbles grabs on to those holes
Heavy candy sinks to the bottom of the soda and pushes the up and out of the bottle

8. So what else works?
Scientists had fun trying numerous experiments by changing the carbonated beverage and the candy treat which were combined…
Mountain Dew and M & M’s
Root Beer and Lifesavers
Sprite and Jolly Ranchers
They all work… but Diet Coke and Mentos create the largest geyser due to the size of the candy, the weight of the candy and the ingredients in the carbonated beverage with an increased amount of carbon dioxide CO2
Shockingly enough… dropping just about anything into just about any kind of soda creates a little fizz.

9. Here is our challenge…
We need to design an insertion device to deliver the Mentos candies into the Diet Coke bottle.
The ideal condition for achieving high-flying geysers is to get as many Mentos as possible into the diet soda at the same or nearly the same time.
Increasing the number of Mentos that are dropped in the soda will increase the spray.
The device should be able to fit into the soda bottle to be able to deliver the candies to create the eruption!
The record geyser is 29 feet set by a Grandmother and her Grandson during summer vacation!

10. Materials for our experiment…
Materials for Geyser:
Diet Coke (2 liter bottle)
Mint Mentos Candy(7)
Measuring tape
Tarp
Goggles
Materials for insertion device:
Paper
Paper clips (4)
String
Tape
Scissors
The device must be activated while the team is away from the bottle of soda to avoid a “SODA SHOWER.”

11. Variables in our experiment…
Independent Variable:
Style of Mentos Entry (insertion device)
Dependent Variable:
Height of Geyser
Constant:
Volume of Diet Coke bottle
Shape of Diet Coke bottle
Temperature of Diet Coke
Number of Mentos Candies

12. Instructions for experiment…
Go outside (Mr. Ballew would not be happy if we got Diet Coke all over the portable )
Unwrap the Mentos candies (6 per team)
Stand the Diet Coke bottle upright, unscrew lid
Team will place insertion device on the bottle
Team will activate their insertion device to drop the Mentos into the Diet Coke Bottle
Team will back away and
watch the eruption!

13. Fun with nucleation at home…
You can learn more about nucleation (tiny holes like on the surface of a golf ball) with an experiment at home:
Coat the inside of a small glass with vegetable oil
Move the glass around, oil all over the sides of the glass
Pour soda into the glass
What happens?
No fizz. Why?
No nucleation sites. The oil removed any holes.
Now sprinkle in some granulated sugar.
Lots of fizz! Why?
Lots of nucleation sites!

14. Make a diet coke mentos rocket…

15. Myth busted…
MYTH: Can COMBINING DIET COKE AND MENTOS MAKE YOUR STOMACH EXPLODE?
Finding: BUSTED
Explanation: Ever have one of those days when you have to eat lunch out of a vending machine? Anyone whose heard the Internet-fueled rumor about the guy who ruptured his stomach by downing Diet Coke and Mentos will probably avoid that combination . Yet, as with like many cyber sensations, there's a lot of hot air behind the Diet Coke and Mentos rumor.
It's true that if you drop a pack of the chewy mints into a 2- liter bottle of Diet Coke, the candy's properties react with the carbon dioxide in the soda to spew forth fizz.
However, when you open and drink a Diet Coke, it releases much of the pressurized carbon dioxide that forms the carbonation. As the soda warms while traveling to the stomach, the gas continues to vaporize. Any remaining might cause your stomach to expand, but it isn't enough to spark a dangerous gassy rebellion if you chase the soda with a pack of Mentos.
The nutritional value of a Diet Coke and Mentos snack is still questionable, but if that's your only vending machine vice, your stomach should make it through just fine.

16. How can we apply what we learned from this challenge to a s. t. e. m
How can we apply what we learned from this challenge to a s.t.e.m. career?
How can we apply what we learned from this challenge to real life?
How did we apply what we learned from other S.T.E.M. challenges to this challenge?

17. Cool s.t.e.m. job- chemical engineer
 Chemical engineers are responsible for the production of items, “from microchips to potato chips.” Chemical engineers work in the chemical, fuel, aerospace, environmental, food, and pulp and paper industries, among many others. Responsibilities range from research and design to development, production, technical sales, and, for those with good communication skills, management. Chemical engineering is a problem- solving profession ; expect to answer the question “how” more than any other. Chemical engineers translate the discoveries chemists make into real-world products. Chemical engineers work in teams, mostly for large corporations. Good chemical engineers are always trying to refine their systems, improve them, and make them safer and more efficient.