Mentos and coke what is the chemical reaction

However, once the CO 2 concentration drops below the critical value, the CO 2 can no longer degas. Therefore, because boiling removes all dissolved CO 2 but Mentos addition does not, the former causes a larger pH shift than the latter. The rainbow of colors observed when boiling club soda to which universal indicator was added was a real treat for me to observe. What a simple experiment: add the indicator to club soda, boil the resulting mixture, and watch the rainbow slowly unfold over time!

Most sodas do not display such a drastic color change, given that they have acidic additives such as citric acid, instead of the potassium bicarbonate and potassium citrate in club soda. These simple demonstrations can be used to talk about a variety of concepts: chemical vs. As CO 2 in the atmosphere increases, the amount of CO 2 dissolved in the ocean increases Equation 1 gets driven to the left.

This in turn causes Equations 2 and 3 to be driven to the right, increasing the acidity of the oceans. Indeed, the pH of the oceans has been observed to drop in an effect known as ocean acidification.

As you can imagine there is much concern over the impact that ocean acidification has on marine life. As you can see in Video 2, I used bromocresol green and club soda to get a green-to-blue color change during the Mentos-induced degassing of soda. I also used a home carbonatioin system and bromocresol green to observe a green-to-yellow color change upon pumping CO 2 into water with a home carbonation system.

In Video 3, universal indicator was used to cause a red-to-orange color change. Please drop me a line in the comments if you try this demonstration on your own — or learn how to produce other color changes! Kuntzleman, T. Baur, J. Coffey, T. Diet Coke and Mentos: What is really behind this physical reaction? Gardner, D. Educator , 19, — Huber, C. Quantifying the Soda Geyser. Sims, T. Kuntzleman et. Analyzing data in 9—12 builds on K—8 and progresses to introducing more detailed statistical analysis, the comparison of data sets for consistency, and the use of models to generate and analyze data.

Asking questions and defining problems in grades 9—12 builds from grades K—8 experiences and progresses to formulating, refining, and evaluating empirically testable questions and design problems using models and simulations. Scientific questions arise in a variety of ways. The rough, dimply surfaces of Mentos encourage bubble growth because they efficiently disrupt the polar attractions between water molecules, creating bubble growth sites. Low surface tension also helps bubbles grow quickly.

Measurements showed that the surface tension in water containing the sweetener aspartame is lower than in sugary water, explaining why Diet Coke creates more dramatic fountains than sugary Coke.

Another factor is that the coatings of Mentos contain gum arabic, a surfactant that further reduces surface tension in the liquid.

Rough-surfaced mints without the surfactant did not create such large fountains. Their results showed that increasing the levels of all of these compounds increased the heights of the fountains obtained by as much as six times when Mentos were added, and at quantities usually found dissolved in commercial carbonated drinks.

The exception was citric acid, which did increase fountain height too, but which required slightly more than usually used in drinks. This is because some of the compounds tested actually increase surface tension when they are dissolved in water.

The proposed explanation for this is that the dissolved compounds may actually be affecting how the bubbles themselves behave, and it is this combined with factors relating to surface tension that influences fountain height. Investigating further, it was found that when the substances were dissolved in water, the bubbles produced were smaller.

Bubble size, it turns out, is inversely proportional to the height of the Coke geyser; the smaller the bubbles, the greater the height achieved. The dissolved substances in the drink were stopping the smaller bubbles combining into bigger bubbles. When the bubbles are smaller, there is a greater surface area for the carbon dioxide still dissolved in the solution to escape into, so the degassing of the carbonated drink happens faster — giving a higher fountain.

This may be the focus for further experiments. If you could look at the straw, pipe cleaner, and Mento with a super-strong microscope you would see that they have tiny dents, scratches, and bumps on them.

There is a pretty cool thing you can do with a bottle of soda pop and a packet of Mentos. Wrap the paper around the pack of Mentos to make a tube. Use masking tape to tape the tube closed. Remove the pack of Mentos from the tube. Close off one end of the tube by cutting a little circle or square of paper and taping it to one end of the tube.

Put the open end of your tube of Mentos on the card and place it directly over the opening of the soda bottle. When you are ready, remove the card and let all the Mentos drop into the soda at once and quickly move out of the way. The carbon dioxide molecules attach to the surfaces of the Mentos like they did in the cup of soda.