Transcript The Famous Coke and Mentos Eruption

By: Courtney Horvat,
Gary Kleinschmidt,
and Casey Kelby
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Steve Spangler began the
phenomenon when he
appeared on 9 News in
2002 and again in 2005
Eepybird.com continued
the trend when a video
featuring Fritz Globe and
Stephen Voltz recreated
the eruption with
multiple fountains
mirroring the fountain
display at the Bellagio in
Las Vegas
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World Record: 1,911
simultaneous geysers
by students of Latvia’s
School of Business
Administration Turbia
Besides becoming an
almost instant internet
trend, it has also been
seen on a variety of TV
shows including
Numb3ers, Bones, and
Myth Busters
Many websites feature
Mentos and coke video
contests
Eepybird.com even
provides step by step
instructions (Thank you!)
and sells merchandise
When you drop the Mentos into the
soda, the gelatin and gum Arabic
from the dissolving candy break
the surface tension. This disrupts
the water mesh, so that it takes
less work to expand and form new
bubbles. Each Mentos candy has
thousands of tiny pits all over the
surface. These tiny pits are called
nucleation sites - perfect places
for carbon dioxide bubbles to
form. As soon as the Mentos hit
the soda, bubbles form all over the
surface of the candy.
Couple this with the fact that the
Mentos candies are heavy and sink
to the bottom of the bottle and
you've got a double-whammy.
When all this gas is released, it
literally pushes all of the liquid up
and out of the bottle in an
incredible soda blast. (Steve
Spangler Science)
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We went out and bought 40 bottles of Sprite
and 40 bottles of coke (16 oz), Then we
bought a few 6-packs of Mentos rolls
We made a stand out of scrap wood to angle
the bottle at 45° from the horizontal to give
the best trajectory and used a rubber band to
fasten the bottle to the stand
We made cartridges out of bottle caps with
holes in them, and strung Mentos on fishing
line to eliminate errors when dropping in the
Mentos
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Then we would place the bottle on the stand,
quickly take off the cap, replace it with the
cartridge and release the Mentos
Then we would measure the furthest spray
To measure weight, we measured the weight
of the soda (weight of bottle minus weight of
empty bottle, then compared it to weight of
fluid in full bottle)
What Happens Next?
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We wanted to see
whether the Diet
Coke and Mentos
eruption would go
farther than the
Sprite and Mentos
eruption, as stated
on Eepybird.com
Perrier, Coke, Sprite, Diet Coke.
(Wikipedia)
350
300
Diet Coke
250
Distance
(inches)
200
150
Sprite
100
Distance
(inches)
50
0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40
Diet Coke
Sprite
Mean
237.0
173.5
Standard
Deviation
9.28
50.7
Min
56
36
Q1
216.3
148.3
Median
250.5
182.0
Q3
275.2
209.1
Max
313
253
IQR
58.8
60.8
Ho :  dc   s
Ha :  dc   s
xdc  237.2
S dc  58.9686
ndc  40
xs  173.525
S s  50.696
ns  40
Assumptions:
2 independent SRS → assumed
Normal population or n≥30 →
n=40≥30
xdc  xs
t
S dc
2
ndc

Ss
 5.17865
2
ns
P(t  5.17865| df  76.2831)  8.8265107
We reject Ho because p-value at 8.8265×10-7
is < α=0.05. We have sufficient evidence that
the difference between the average of diet coke
is greater than the average of sprite.
2
2
sdc
ss
( xdc  xs )  t *

 (39.187,88.163)
ndc ns
We are 95% confident that the difference
in the average spray distance of Diet
Coke and Sprite is between 39.187 and
88.163 inches.
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For our second
experiment, we
wanted to see if the
eruption displaced
half of all the
liquid, so we
weighed the liquid
and tested our
results…
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Min: 5.4
Q1: 10.4
Med: 11.4
Q3: 12.275
Max: 12.9
Mean: 10.906
Std. Dev.: 1.753
Ho :  d  .5
Ha :  d  .5
xd  11.0726
Sxd  1.71479
n  40
  .05
df  39
Assumptions:
2 dependant SRS → assumed
(before and after)
n≥30 → n=40≥30
x
t
 41.1583
S
n
p(t  41.15823| df  39)  9.49511034
We reject Ho because p-value at 9.4951×10-34 is <
α=0.05. We have sufficient evidence that the average
difference of net weight after the eruption is not equal to
half the original weight.
 sd 
xd  t * 
  10.524,11.621
 n
We are 95% confident that the average
difference in the net weight of the liquid
remaining in the bottles after eruption
of Diet Coke and Mentos is between
10.524 and 11.621 fluid ounces.
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Weather/
Temperature
◦ Heat as a factor in
experiment: the
warmer the better
◦ Wind
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Exact measurements
Drilling/Threading
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◦ Cracked some shell
and lost some of
nucleation sights
Overspray under cap
◦ Not enough time to
screw it on all the way
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◦ Scale
◦ Measuring Spray
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Fishing line caught,
hands in the way
Shaken soda/CO2
released between cap
exchange
Holes in cap caused
angle in spray
Overall the project was
fun and interesting
with all the science
behind it
While we may have had
errors and biases, we
performed our
experiment to the best
of our ability
We feel that our results
are accurate and that
our methods helped us
to achieve our accuracy
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Diet coke is the best soda to use out of the
Sprite/Diet Coke test
When doing a Diet Coke and Mentos
experiment, the net weight loss will not
equal half of all the weight