Why does cola react with mentos

The bubbles are made of a gas called carbon dioxide. The soda company puts carbon dioxide in the soda to make the soda fizzy. 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. All those Mentos in a lot of soda make a lot of bubbles that rise to the surface and push the soda out in a big woosh! If you videotaped the reactions, you can watch your videos now.

What do you notice from the videos? Use a tape measure and blue painter's tape to mark off the height from the top of the bottle in meters.

Then repeat this activity three times, with the bottle in front of the tape-marked wall, video taping it each time.

When you review the recordings, use slow motion and pause the recording when the spout is at its maximum height. Using the tape marks in the background, estimate the height of the spout. Calculate the average height of the fountains for the whole and for the crushed Mentos. What is the difference in height of the eruptions? You can try testing different kinds of carbonated beverages, different kinds of candies with different shapes and textures or using other things to start the reaction, like rock salt, pennies or dice.

Which beverages, candies or other things cause the largest and smallest fountains? Why do you think this is? Does temperature affect the eruption height? Observations and results Was the eruption higher when whole Mentos candies were used compared with crushed candies? Was less Diet Coke left in the bottle after the reaction with the whole candies compared with the crushed ones? In the Diet Coke bottle the Mentos candy provides a rough surface that allows the bonds between the carbon dioxide gas and water to break more easily, helping to create carbon dioxide bubbles.

As the Mentos candy sinks in the bottle, the candy causes the production of more and more carbon dioxide bubbles, and the rising bubbles react with carbon dioxide that is still dissolved in the soda to cause more carbon dioxide to be freed and create even more bubbles, resulting in the eruption. Because Mentos candies are rather dense, they sink rapidly through the liquid, causing a fast, large eruption. The crushed Mentos candies, however, are not as dense as the whole ones, which causes them to sink more slowly, creating a relatively small cola fountain, which should also leave more liquid in the bottle than the larger eruption with whole Mentos candies did.

Cleanup Hose off any part of a building that was splashed with Diet Coke. If you try this project with regular Coke, the eruption should still happen but its sugary content may make cleaning more difficult. This activity brought to you in partnership with Science Buddies. Already a subscriber? Sign in. To find out more, Coffey and a team of students tested the reactions between Diet Coke and fruit Mentos, mint Mentos, and various ingredients such as other mints, dish-washing detergent, table salt and sand.

They also compared reactions using other fizzy liquids such as caffeine-free and sugary colas, as well as soda water and tonic water. The results showed that Diet Coke created the most spectacular explosions with either fruit or mint Mentos, the fountains travelling a horizontal distance of up to 7 metres. But caffeine-free Diet Coke did just as well, suggesting that caffeine does not accelerate the reaction, at least at the normal levels in the drink.

Measurements of the pH of the Coke before and after the experiments showed that its acidity did not change, ruling out the idea that a simple acid-base reaction drives the fountains. Instead, the vigour of the jets depends on various factors that affect the growth rate of carbon dioxide bubbles. 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.