Greenwood press

160
VOLUME

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dimensions need to be measured so that an appropriate amount of cement is
brought to the site. Suppose a driveway 12 feet wide and 30 feet long is needed
for a new home, and the cement poured needs to be 1.25 feet deep so that it will
not break apart under pressure from automobiles or extreme temperatures. The
volume of cement needed to complete this job can be determined by the product
of its dimensions, since the cement will fill into a rectangular prism. Therefore
the amount of cement needed is (12)(30)(1.25) = 450 cubic feet. If a bag of
cement mixture prepares 0.75 cubic feet of concrete, then the cement truck will
need to contain 600 bags of mixture in order to create the driveway. Since each
bag is about a hundred pounds, multiple trucks will be needed to carry the 60,000
pound load.
The dispersion of an oil spill can be predicted based on the amount of oil that
is lost. On March 24, 1989, the oil tanker Exxon Valdez struck Bligh Reef in
Prince William Sound, Alaska, spilling more than 11 million gallons of oil. There
are 231 cubic inches in a gallon, so the spill had an approximate volume of 254
billion (231 
× 11,000,000 = 254,100,000,000) cubic inches of oil. Thousands of
marine animals and fish were killed by the oil that contaminated the water. As oil
spreads, it typically leaves a layer that is 1/100 inch thick on the surface of the
water. The direction of the spill is influenced by the placement of the spill and
the direction of the ocean’s current. In this circumstance, much of the oil had
brushed on shore, at the beaches. What if the spill had happened in the middle of
the ocean? Imagine the effect of spilling water in an open space on the floor.
Assuming that the floor is flat, the spill will disperse in nearly a circular region.
If the oil had spilled in the middle of the ocean without land interference, the spill
could have covered nearly 2.5 billion (254,100,000,000 
⋆ 1/100) square inches
of the surface of the water. If the path of the oil dispersed in the shape of a cir-
cle, then it could have spread in a radius of close to half a mile. This information
can be determined by solving for 
r in the equation πr
2
= 2,541,000,000, and then
converting the inch units to miles. There are 5,280 feet in one mile, and 12 inches
in a foot. Therefore the conversion is 5,280 
× 12 = 63,360 inches for every mile.
Benjamin Franklin was one of the first to determine that very little oil will spread
out over a huge area of water. His work actually gave one of the first estimates
of the thickness of a molecule of oil, even though no one in Franklin’s time knew
about molecules.
online sources for further exploration
Aluminum tanks

Application to environmental health

Balloon volumes