Pressure in the Diet Coke^{TM} & Mentos^{TM} Reaction
Objective
Perform a series of experiments on the reaction between Diet Coke^{TM} and Mentos^{TM} candies. Use the data to estimate what the pressure would be inside a sealed 2 L bottle of Diet Coke with 5 Mentos mints.Plan
Your plan should include the following information, but in your own words.
- Make a Diet Coke & Mentos fountain.
- Set off your fountain & measure the height of the spray.
- Repeat with caps that have different size holes.
Procedure
Write out your detailed procedure. Be sure to descrbe how you made the fountain (include a labeled diagram, the size of the bottle of Diet Coke, number of Mentos and how you attached them together, etc.):
and how you measured the height of the spray, using a ruler as a scale hypsometer.
(In the above example, the height of the spray would be 4.5m.)
Data & Observations
Here are data for each of the honors Physics classes:
Block | Diameter of hole (mm) |
Dist. to 2m mark (cm) |
Height of 2m mark (m) |
Dist. to top of spray (cm) |
Height of spray (m) |
Pressure (Pa) |
A | 4.0 | 11.5 | 2.0 | 40.0 | ||
A | 4.8 | 9.0 | 2.0 | 34.0 | ||
A | 4.8 | 11.5 | 2.0 | 39.0 | ||
A | 5.6 | 12.0 | 2.0 | 36.0 | ||
E | 4.0 | OOPS | 2.0 | 39.0 | ||
E | 4.0 | 14.0 | 2.0 | 42.0 | ||
E | 4.8 | 8.0 | 2.0 | 28.0 | ||
E | 4.8 | 12.0 | 2.0 | 32.0 | ||
E | 5.6 | 11.5 | 2.0 | 37.5 | ||
E | 5.6 | 13.5 | 2.0 | 42.0 |
Analysis
Calculate the pressure in each bottle using the equation P = Ïgh, with Ï = 998 kg/m^{3}, g = 9.8 m/s^{2}, and h as calculated from your measurements. Use the data from your class. If you choose to leave out one or more data points, be sure to include an explanation!
Plot a graph of pressure vs. diameter of the opening. Draw a best-fit line and extrapolate to an opening of 0 mm to find the pressure that would be present in a bottle with no opening.
An example graph with sample data is shown below:
- Calculate the y-intercept graphically, plotting your data points accurately on graph paper and drawing the best-fit line with a straightedge.
- Calculate the best-fit line and y-intercept statistically, using linear regression. If you do this, be sure to provide the slope, intercept, and correlation coÃ«fficient.
Links
- Science of Mentos-Diet Coke explosions explained (article in New Scientist)
- Diet Coke and Mentos Super Fountains! (a Do-It-Yourself guide from Fritz Grobe and Stephen Voltz, the "mad scientists" at eepybird.com).