thermodynamics of popcorn michael bachmann, tony ghaly, kathlyn herrick, sean rodney ireland, brian...
TRANSCRIPT
Thermodynamics of Popcorn
Michael Bachmann, Tony Ghaly, Kathlyn Herrick, Sean Rodney Ireland, Brian Lewis, Mohit Moondra, Neel Patel, Evan Rosenman, Juliet Savits
Advisor: Paul Victor Quinn Sr. Assistant: Evan Kimberly
History of Popcorn
• New Mexico’s Bat Cave
• Aztecs• The Great Depression• Movie Theaters
Why Fluffier Popcorn?• The demand for corn is skyrocketing
– Biofuel consumes about 1/4 of corn crop
– Price has risen from ≈$2.40 to over $3.30– Tortilla prices in Mexico have doubled
• Efficient popcorn is paramount– 40% rise in popcorn prices from 2006 to 2007
S
D
Why Fluffier Popcorn? (cont’d)
• 30% of popcorn is consumed outside the home
– About 5 BILLION quarts at films, stadiums, etc.– Prepopped popcorn is also popular in the home
• Economies of scale are possible– A 10-15% efficiency rise could
mean big profit rise for 36 oz. popper– High market value of popcorn would
offset the cost of vacuum• Few cents of corn pop a $5 dollar bucket
Thermodynamics
• Ideal Gas
PV=nRT
• Adiabatic ProcessP1V1
γ= P2V2γ
• .
Goals
• Increase size of popped kernels (π)
• Increase volume per mass (σ)
• Decrease number of unpopped kernels (ω)
Microwave Apparatus
Microwave ApparatusProcedure
• 10 g. bag samples in microwave chamber
• Vacuum pump reduces pressure
• Pop for 2 minutes 15 seconds
• Measure volume and calculate σ, π, ω
Expansion Volume (σ) vs. Pressure
Flake Size (π) vs. Pressure
Waste Percentage (ω) vs. Pressure
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0 5 10 15 20 25 30 35
Pressure (in. Hg less than atmospheric pressure)
ω (
kern
els
un
po
pp
ed/t
ota
l ker
nel
s) y= 0.534exp(-0.276x)+0.101RMSE = .0379
Variables Affecting Microwave
• Age of popcorn kernels
• Limitations of bags
• Lifetime of microwave
• Inconsistency with timing
Movie Maker Apparatus
Movie Maker ApparatusProcedure
• 85 g. samples
• Vacuum pump lowers pressure
• Release vacuum after popping
• Measure volume and calculate σ, π, ω
Expansion Volume (σ) vs. Pressure
y = 0.3001x + 38.177
R2 = 0.9928
0
5
10
15
20
25
30
35
40
45
50
0 5 10 15 20 25
Pressure (in. Hg less than atmospheric pressure)
σ(m
L/g
ram
)
Flake Size (π) vs. Pressure
The Popcorn Pot
Popcorn Pot Procedure
• Pre-heat 20 minutes• 20 g. samples• Vacuum pump lowers pressure• Periodically shake pot• Release vacuum and turn off heat• Measure volume and calculate σ, π, ω
Expansion Volume (σ) vs. Pressure
Flake Size (π) vs. Pressure
Waste Percentage (ω) vs. Pressure
Expansion Volume (σ) Comparison
0
5
10
15
20
25
30
35
40
45
50
Microwave Movie Maker Popcorn Pot
σ (
mL
/g)
Atmospheric Pressure
Reduced Pressure
• Decreased pressure increased volume.
Flake Size (π) Comparison
0
1
2
3
4
5
6
7
8
Microwave Movie Maker Popcorn Pot
π (
mL
/nu
mb
er o
f fl
akes
)
Atmospheric Pressure
Reduced Pressure
• Decreased pressure increased individual flake size.
Percent Waste (ω) Comparison
0
10
20
30
40
50
60
70
Microwave Movie Maker Popcorn Pot
ω (
Per
cen
tag
e)
Atmospheric Pressure
Reduced Pressure
• Decreased pressure decreased percent waste for microwave and popcorn pot.
Conclusions
• Decreased pressure resulted in increased volume
• Microwave best demonstrated theory
• Movie Maker is most practical application