Diet Coke and Mentos What is really behind this physical reactionTon - PDF document

1 Diet Coke and Mentos: What is really beh
Diet Coke and Mentos: What is really behind this physical reaction?Tonya Coffey*Publish

2 ed in the American Journal of Physics, J
ed in the American Journal of Physics, June 2008 Diet Coke and Mentosis a major stshow

3 n on the Letterman show in 1999 by chemi
n on the Letterman show in 1999 by chemistry teacher Lee MarekSubject of a 2006 episode

4 of Mythbusters Subject of countless You
of Mythbusters Subject of countless YouTube videos Why on earth do I care so much abou

5 t Mentos? students the experience of par
t Mentos? students the experience of participating in a real research project, not a ca

6 nned lab.But I admit the project explode
nned lab.But I admit the project exploded beyond my original vision… solubility of COra

7 pidly--hence the "explosive" evolution o
pidly--hence the "explosive" evolution of CO •Adding surfactants to •Surfactants are lo

8 ng •For temperature dependent trials we
ng •For temperature dependent trials we •Other bottles were heated in a water •This ma

9 y have caused some systematic •Soda temp
y have caused some systematic •Soda temperature was measured with Which soda ingredien

10 ts cause the biggest reaction? Results—M
ts cause the biggest reaction? Results—Mass lost during reaction of Mentosin 125013001

11 35014001450Mass Lost (g) Ranking Caffein
35014001450Mass Lost (g) Ranking Caffeine Free CokeCokeCaffeine Free Diet CokeDiet Coke

12 Presence/absence of aspartame matters mo
Presence/absence of aspartame matters more than presence/absence of caffeine. •Matters

13 a little, but the differences are •The M
a little, but the differences are •The Mythbustersadded “enough caffeine to kill you”an

14 d saw a reaction. Hopefully •To answer
d saw a reaction. Hopefully •To answer this question, we took contact angle 

15  cos2cos12f +/-3
 cos2cos12f +/-3 degrees) Contact Angle Results 231,2,20lnffWWL

16 VLVHsoAbove, we assumed that the liquid-
VLVHsoAbove, we assumed that the liquid-vapor surface tension was reduced by 5% for the

17 second system ascompared to the de-ioni
second system ascompared to the de-ionized water (system 1). The smaller the ratio, th

18 e less work is required to form a bubble
e less work is required to form a bubble.Aspartame reduces the work more than sugar.Pot

19 assium benzoate, the preservative they a
assium benzoate, the preservative they add to beverages containing aspartame (like Diet

20 Coke) is even better. 90010001100120013
Coke) is even better. 900100011001200130014001500 Horizontal Distance Traveled by Spra

21 y (ft)Mass Lost during Reaction (g)Molec
y (ft)Mass Lost during Reaction (g)Molecular Sieve Pump BeadsCake Mates 900100011001200

22 130014001500 Horizontal Distance Travele
130014001500 Horizontal Distance Traveled by Spray (ft)Mass Lost during Reaction (g)Mol

23 ecular Sieve Pump BeadsCake Mates mass l
ecular Sieve Pump BeadsCake Mates mass lost and distancetraveled. Roughness: SEM imag

24 es of Samples Mint MentosLarge surface a
es of Samples Mint MentosLarge surface area tovolume ratio means moregrowth sites!We ca

25 n get a qualitative feel for the roughne
n get a qualitative feel for the roughness of samples with SEM, but not get quantitativ

26 e. Unfortunately, we couldn’t image all
e. Unfortunately, we couldn’t image all of our samples in AFM due to sample height var

27 iation restrictions. •It’s not an acid/b
iation restrictions. •It’s not an acid/base reaction. •Higher temperatures mean bigger

28 explosions.•The aspartame and potassium
explosions.•The aspartame and potassium benzoate in the Diet •There’s not enough caffe

29 ine to matter much.•A faster explosion i
ine to matter much.•A faster explosion is more impressive than a slower one.•The quick

30 reaction time, and rough surface combine
reaction time, and rough surface combined make it the most explosive. Fruit Mentoshave