Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Students Explore the Physics of Fizz

13.06.2008
Students use the principles of physics to explain the Mentos-Diet Coke reaction.

Just about everyone knows what happens when you drop Mentos mints into a Diet Coke.

Students at Appalachian State University have documented why the reaction occurs by studying the physics responsible for the fizzy result. Their results have been published in the June 2008 issue of the American Journal of Physics.

Tonya Coffey, an assistant professor of physics at Appalachian, developed the research project to as a way for sophomore-level students to build on skills they learned in their freshmen physics courses.

Through a series of experiments, the students found that a reaction between the rough surface of the Mentos, and the potassium benzoate and aspartame contained in Diet Coke were responsible for the famous geyser reaction, in which the liquid can spew up to 30 feet.

In the process, they also learned about the principles of thermodynamics, fluid mechanics, surface science and the physics of eruptions.

“We try to teach students what real experiments are like,” Coffey said. “I thought it would be good for the students to work on an experiment that doesn’t have a known outcome—because that’s what research is.”

Coffey asked her students to find out everything they could about the Diet Coke and Mentos reaction, develop a question about the reaction and design an experiment to answer their question. The students’ only restrictions were to design an experiment that could be accomplished on a tight budget and to use existing equipment at the university.

“We discussed what a real researcher has to do when designing an experiment to answer a question,” Coffey said. Students studied what makes a good experiment, how complications can arise, the need to narrow the number of unknowns in an experiment, and the importance of designing an experiment that tests for one variable at time.

The students measured the volume of liquid displaced and the distance it traveled when a variety of items were added to Diet Coke – including Mentos, Wint-O-Green Lifesavers, rock salt, table salt and sand.

They also studied the surface roughness of the candy and other materials by using a scanning electron microscope and an atomic force microscope.

So why does the reaction occur? In an opened container of soda, carbon dioxide gas bubbles out over the course of minutes or hours until the concentration of carbon dioxide left in the soda is proportional to the carbon dioxide in the surrounding air. This de-fizzing reaction is slow because the surface tension of the liquid is very high, which keeps the gas bubbles trapped.

But when a Mentos is dropped in the beverage, it breaks the surface tension and as it falls the candy’s surfactant coating further reduces the surface tension of the liquid. The candy’s rough surface also provides growth sites for the gas, making it easier for carbonation to escape as a foam geyser.

The geyser also occurs when sand, salt or lifesavers were added to the Diet Coke, but the mass lost and volume traveled is much less spectacular.

Tonya Coffey | newswise
Further information:
http://www.appstate.edu

More articles from Physics and Astronomy:

nachricht Atoms at the photo shoot
03.08.2020 | Humboldt-Universität zu Berlin

nachricht Collisions in the solar system: Bayreuth researchers explain the origins of stony-iron meteorites
03.08.2020 | Universität Bayreuth

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: TU Graz Researchers synthesize nanoparticles tailored for special applications

“Core-shell” clusters pave the way for new efficient nanomaterials that make catalysts, magnetic and laser sensors or measuring devices for detecting electromagnetic radiation more efficient.

Whether in innovative high-tech materials, more powerful computer chips, pharmaceuticals or in the field of renewable energies, nanoparticles – smallest...

Im Focus: Tailored light inspired by nature

An international research team with Prof. Cornelia Denz from the Institute of Applied Physics at the University of Münster develop for the first time light fields using caustics that do not change during propagation. With the new method, the physicists cleverly exploit light structures that can be seen in rainbows or when light is transmitted through drinking glasses.

Modern applications as high resolution microsopy or micro- or nanoscale material processing require customized laser beams that do not change during...

Im Focus: NYUAD astrophysicist investigates the possibility of life below the surface of Mars

  • A rover expected to explore below the surface of Mars in 2022 has the potential to provide more insights
  • The findings published in Scientific Reports, Springer Nature suggests the presence of traces of water on Mars, raising the question of the possibility of a life-supporting environment

Although no life has been detected on the Martian surface, a new study from astrophysicist and research scientist at the Center for Space Science at NYU Abu...

Im Focus: Manipulating non-magnetic atoms in a chromium halide enables tuning of magnetic properties

New approach creates synthetic layered magnets with unprecedented level of control over their magnetic properties

The magnetic properties of a chromium halide can be tuned by manipulating the non-magnetic atoms in the material, a team, led by Boston College researchers,...

Im Focus: A new method to significantly increase the range and stability of optical tweezers

Scientists of Tomsk Polytechnic University jointly with a team of the V.E. Zuev Institute of Atmospheric Optics of the Siberian Branch of the Russian Academy of Sciences have discovered a method to increase the operation range of optical traps also known

Optical tweezers are a device which uses a laser beam to move micron-sized objects such as living cells, proteins, and molecules. In 2018, the American...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“Conference on Laser Polishing – LaP 2020”: The final touches for surfaces

23.07.2020 | Event News

Conference radar for cybersecurity

21.07.2020 | Event News

Contact Tracing Apps against COVID-19: German National Academy Leopoldina hosts international virtual panel discussion

07.07.2020 | Event News

 
Latest News

Novel approach improves graphene-based supercapacitors

03.08.2020 | Information Technology

Germany-wide rainfall measurements by utilizing the mobile network

03.08.2020 | Information Technology

Drug discovery: First rational strategy to find molecular glue degraders

03.08.2020 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>