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APPLYING SCIENCE TO THE REAL WORLD Science and Society
Concepts Applied These readings relate the chapter’s content to current societal
issues. Many of these boxes also include Questions to Discuss
Each chapter also includes one or more Concepts Applied
that provide an opportunity to discuss issues with your peers.
boxes. These activities are simple investigative exercises that
students can perform at home or in the classroom to demon-
strate important concepts and reinforce understanding of Myths, Mistakes, and Misunderstandings
them. This feature also describes the application of those con- These brief boxes provide short, scientific explanations to dispel
cepts to everyday life. a societal myth or a home experiment or project that enables
you to dispel the myth on your own.

light in a transparent substance. A glass prism separates sunlight
into a spectrum of colors because the index of refraction is dif- The nature of light became a topic of debate toward the end
ferent for different wavelengths of light. The same processes that of the 1600s as Isaac Newton published his particle theory of
slow the speed of light in a transparent substance have a greater light. He believed that the straight-line travel of light could
effect on short wavelengths than they do on long wavelengths. As be better explained as small particles of matter that traveled at
a result, violet light is refracted most, red light is refracted least, great speed from a source of light. Particles, reasoned Newton,
and the other colors are refracted between these extremes. This should follow a straight line according to the laws of motion.
results in a beam of white light being separated, or dispersed, into Waves, on the other hand, should bend as they move, much
a spectrum when it is refracted. Any transparent material in which as water waves on a pond bend into circular shapes as they
the index of refraction varies with wavelength has the property move away from a disturbance. About the same time that
of dispersion. The dispersion of light by ice crystals sometimes Newton developed his particle theory of light, Christian
produces a colored halo around the Sun and the Moon. Huygens (pronounced “ni-ganz”) (1629–1695) was conclud- Science and Society
ing that light is not a stream of particles but rather a longitu-
CONCEPTS Applied dinal wave. Costs of Mining Mineral Resources
Both theories had advocates during the 1700s, but the
majority favored Newton’s particle theory. By the beginning of ncient humans exploited mineral quantities of water for the extraction or an eyesore, and it is difficult for vegetation
Colors and Refraction A resources as they mined copper miner- concentration of a mineral resource. If to grow on the barren rock. Since plants are
the 1800s, new evidence was found that favored the wave the-
A convex lens is able to magnify by forming an image with ory, evidence that could not be explained in terms of anything als for the making of tools. They also used the energy and water are not readily avail- not present, water may wash away small rock
refracted light. This application is concerned with magni- but waves. salt, clay, and other mineral materials for able, the resource cost might be converted particles, causing erosion of the land and
to economic cost, which could ultimately
fying, but it is really more concerned with experimenting nutrients and pot making. These early peo- determine whether the operation will be silting of the streams. The debris might also
ple were few in number, and their simple
contain arsenic, lead, and other minerals that
to find an explanation. tools made little impact on the environ- profitable. Finally, the third category is the can pollute the water supply.
Here are three pairs of words: ment as they mined what they needed. As environmental cost of mining the resource. Today, regulations on the mining
INTERFERENCE
SCIENCE BOOK the numbers of people grew and technology Environmental cost is converted to eco- industry require less environmental dam-
RAW HIDE In 1801, Thomas Young (1773–1829) published evidence of advanced, more and more mineral resources nomic cost as controls on pollution are age than had been previously tolerated.
CARBON DIOXIDE a behavior of light that could only be explained in terms of were utilized to build machines and pro- enforced. It is expensive to clean pollution The cost of finding and processing the
minerals is also increasing as the easiest
from the land and to restore the ecosystem
vide energy. With advances in population
a wave model of light. Young’s experiment is illustrated in
Hold a cylindrical solid glass rod over the three pairs and technology came increasing impacts that was changed by mining operations. to use, less expensive resources have been
of words, using it as a magnifying glass. A clear, solid, and Figure 7.19A. Light from a single source is used to produce two on the environment in both size and scope. Consideration of the conversion of environ- utilized first. As current mineral resource
transparent plastic rod or handle could also be used as a beams of light that are in phase, that is, having their crests and In addition to copper minerals and clay, the mental cost to economic cost can also deter- deposits become exhausted, pressure will
magnifying glass. troughs together as they move away from the source. This light metal ores of iron, chromium, aluminum, mine if a mining operation is feasible or not. increase to use the minerals in protected
Notice that some words appear inverted but others falls on a card with two slits, each less than a millimeter in width. nickel, tin, uranium, manganese, platinum, All mining operations start by mak- areas. The environmental costs for utiliza-
do not. Does this occur because red letters are refracted The light moves out from each slit as an expanding arc. Beyond cobalt, zinc, and many others were now in ing a mineral resource accessible so it can tion of these areas will indeed be large.
high demand.
be removed. This might take place by strip
differently than blue letters? the card, the light from one slit crosses over the light from the Today, there are three categories of mining, which begins with the removal of
Make some words with red and blue letters to test your other slit to produce a series of bright lines on a screen. Young costs recognized with the mining of any the top layers of soil and rock overlying a QUESTIONS TO DISCUSS
explanation. What is your explanation for what you observed? mineral resource. The first category is the resource deposit. This overburden is placed Divide your group into three subgroups:
had produced a phenomenon of light called interference, and
interference can only be explained by waves. economic cost, the money needed to lease or somewhere else, to the side, so the mineral one representing economic cost; one,
buy land, acquire equipment, and pay for deposit can be easily removed. Access to a resource cost; and one, environmental
labor to run the equipment. The second cat- smaller, deeper mineral deposit might be cost. After a few minutes of preparation,
egory is the resource cost of mining. It takes gained by building a tunnel to the resource. have a short debate about the necessity
energy to concentrate the ore and trans- The debris from building such a tunnel is of having mineral resources at the lowest
port it to smelters or refineries. Sometimes usually piled outside the entrance. The rock cost possible versus the need to protect our
other resources are needed, such as large debris from both strip and tunnel mining is environment no matter what the cost.
Closer Look
One or more boxed Closer Look features can be found in each
The presence of the hydronium ion gives the solution new chemi- been observed to add a pinch of salt to a pot of water before
chapter of Physical Science. These readings present topics of cal properties; the solution is no longer hydrogen chloride but is boiling. Is this to increase the boiling point and therefore
hydrochloric acid. Hydrochloric acid, and other acids, will be dis- cook the food more quickly? How much does a pinch of salt
special human or environmental concern (the use of seat belts, cussed shortly. increase the boiling temperature? The answers are found in
the relationship between the concentration of a solute and the
acid rain, and air pollution, for example). In addition to envi- boiling point of the solution.
Myths, Mistakes, & Misunderstandings It is the number of solute particles (ions or molecules) at
ronmental concerns, topics are presented on interesting techno- the surface of a solution that increases the boiling point. Recall
Teardrops Keep Falling? that a mole is a measure that can be defined as a number of
logical applications (passive solar homes, solar cells, catalytic It is a mistake to represent raindrops or drops of falling water particles called Avogadro’s number. Since the number of par-
ticles at the surface is proportional to the ratio of particles in
with teardrop shapes. Small raindrops are pulled into a spheri- the solution, the concentration of the solute will directly influ-
converters, etc.) or on the cutting edge of scientific research (for cal shape by surface tension. Larger raindrops are also pulled ence the increase in the boiling point. In other words, the boil-
into a spherical shape, but the pressure of air on the bottom of
the falling drop somewhat flattens the bottom. If the raindrop is ing point of any dilute solution is increased proportionally to
example, El Niño and dark energy). All boxed features are too large, the pressure of air on the falling drop forms a concave the concentration of the solute. For water, the boiling point is
depression on the bottom, which grows deeper and deeper until increased 0.521°C for every mole of solute dissolved in 1,000 g
informative materials that are supplementary in nature. The the drop breaks up into smaller spherical drops. of water. Thus, any water solution will boil at a higher tempera-
ture than pure water. Since it boils at a higher temperature, it
Closer Look readings serve to underscore the relevance of also takes a longer time to reach the boiling point.
It makes no difference what substance is dissolved in the
physical science in confronting the many issues we face daily.
A Closer Look People Behind the Science
A Bicycle Racer’s Edge Many chapters also have fascinating biographies that spotlight
alileo was one of the first to recognize likely to have the lower-pressure-producing
Gthe role of friction in opposing motion. air turbulence behind (and resulting greater well-known scientists, past or present. From these People Be-
As shown in Figure 2.9, friction with the sur- pressure in front) because it smoothes, or
face and air friction combine to produce a streamlines, the air flow.
net force that works against anything that is The frictional drag of air is similar to hind the Science biographies, students learn about the human
moving on the surface. This article is about the frictional drag that occurs when you
air friction and some techniques that bike push a book across a rough tabletop. You
riders use to reduce that opposing force— know that smoothing the rough tabletop side of the science: physical science is indeed relevant, and real
perhaps giving them an edge in a close race. will reduce the frictional drag on the book.
The bike riders in Box Figure 2.1 are Likewise, the smoothing of a surface ex-
forming a single-file line, called a pace- BOX FIGURE 2.1 The object of the race posed to moving air will reduce air fric- people do the research and make the discoveries. These read-
line, because the slipstream reduces the air is to be in the front, to finish first. If this is tion. Cyclists accomplish this “smoothing”
re sistance for a closely trailing rider. Cyclists true, why are these racers forming a single- by wearing smooth Lycra clothing and by ings present phys ical science in real-life terms that students can
say that riding in the slipstream of another file line? shaving hair from arm and leg surfaces that
cyclist will save much of their energy. They are exposed to moving air. Each hair con-
can move 8 km/h faster than they would ex- tributes to the overall frictional drag, and identify with and understand.
pending the same energy riding alone. turbulent versus a smooth flow of air and removal of the arm and leg hair can thus
In a sense, riding in a slipstream means (2) the problem of frictional drag. A turbu- result in seconds saved. This might provide
that you do not have to push as much air out lent flow of air contributes to air resistance enough of an edge to win a close race. Shav-
of your way. It has been estimated that at because it causes the air to separate slightly ing legs and arms and the wearing of Lycra “The People Behind the Science features help relate
32 km/h, a cyclist must move a little less than on the back side, which increases the pres- or some other tight, smooth-fitting gar-
one-half a ton of air out of the way every sure on the front of the moving object. This ments are just a few of the things a cyclist
minute. Along with the problem of moving is why racing cars, airplanes, boats, and can do to gain an edge. Perhaps you will be the history of science and the contributions of the
air out of the way, there are two basic fac- other racing vehicles are streamlined to able to think of more ways to reduce the
various individuals.”
tors related to air resistance. These are (1) a a teardroplike shape. This shape is not as forces that oppose motion.
—Richard M. Woolheater, Southeastern Oklahoma State
University
PREFACE xv