Movie Worksheet: Volcano 1997 Cooling Wilshire Boulevard After viewing scenes fr
ID: 153023 • Letter: M
Question
Movie Worksheet: Volcano 1997
Cooling Wilshire Boulevard
After viewing scenes from Volcano, You might have asked, “Could water be used to stop lava from flowing? If so, how much would it take?”
Here’s the situation: a basaltic volcano erupts in the heart of Los Angeles. Lava pours down the streets, destroying buildings, starting fires, and causing general chaos. Tommy Lee Jones organizes firefighters, public works employees, residents, and National Guard helicopters to stop the lava flow. They do this in a matter of minutes by blocking the flow first with concrete traffic barriers, and then chilling it with water pumped by fire hoses and dropped from helicopters.
Is this possible?
Actually, we can figure this out.
The width of the street - building to building – is about 30 m across (~100 ft), and we want to cool and solidify the lava front – say about 150 m (~500 ft) down Wilshire Blvd. We want to solidify it to about a depth of 1 meter (a good solid crust about 3 ft thick). So we have a surface area of 4,500 m2 (length times width), and 1 meter thick gives a total volume of 4,500 m3 of lava to solidify.
Download the Excel spreadsheet “LavaCooling.xls” in order to complete the assignment or you may complete the assignment on the hard copy on the next page.
You will also need two pieces of information:
Total energy needed to cool the lava (term A in spreadsheet) = 8.78 x 1012 Joules
Total energy to heat and boil water (term B) = 2.64 x 106 Joules/kg
Cooling a lava flow on Wilshire Blvd., Los Angeles
Useful information
Carrying capacity of a helicopter: 500 gallons of water
Number of helicopters: 20
Pumping rate of 1 fire truck (if water supplied from city water main via fire hydrants): 1500 gallons/min
Number of fire trucks: 20
WORKSHEET
Total energy needed to cool lava A _________ Joules
Total energy to heat and boil water per kilogram B _________ Joules/kg
Kilograms of water needed = A / B C _________ kg
1 gallon of water (3.8 liters) weighs 3.8 kilograms
Number of gallons of water needed = C / 3.8 D _________ gallons of water total
FINAL ANSWERS
No. helicopter dumps = D / helicopter capacity E _________ dumps
No. trips per helicopter = E / number of helicopters _________ trips
Gallons per minute for 20 fire trucks F _________ gallons/min
Minutes of pumping for 20 fire trucks = D / F _________ minutes of pumping
Explanation / Answer
Answer Worksheets
Total energy needed to cool lavA= 8 78×10^12 joules
Total energy to heat and boil water per kg=2.64×10^6Joules/kg total kg of water needed C=3.33×10^6kg of water
No of gallons needed D= 0.88×10^6= 8.8×10^5 gallons
No of Helicopter dumps= 8.8×10^5/500= 1.76×10^3 dumps
No. Trips per Helicopter=1.76×10^3/20=0.9×10^2=90trips per Helicopter
Gallons per minute for 20 fire truck=1500×20=30000gallons/minute
Minute of pumping for 20 fire trucks=8.8×10^5/30000=2.9×10^2 minutes of pumping
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