shake the foundations of understanding and lead to new
modes of thinking. Thomas Kuhn, philosopher of sci-
ence, called such discoveries paradigm shifts.
Here are some major advances in science.
■
420 B.C.: Hippocrates begins the scientific study
of medicine by maintaining that diseases have
common causes.
■
260 B.C.: Archimedes discovers the principle of
buoyancy.
■
180 A.D.: Galen studies the connection between
paralysis and severance of the spinal cord.
■
1473: Copernicus proposes a heliocentric system.
■
1581: Galileo finds that objects fall with the same
acceleration.
■
1611: Kepler discovers total internal reflection
and thin lens optics.
■
1620: Francis Bacon discusses the principles of
the scientific method.
■
1687: Newton formulates the laws of gravity.
■
1789: Lavoisier states the law of conservation of
energy.
■

1837: Darwin uses natural selection to explain
evolution.
■
1864: James Clerk Maxwell shows that light is an
electromagnetic phenomenon.
– HISTORY AND NATURE OF SCIENCE–
260
N
OW THAT YOU have reviewed the information you need to know, it’s time to think about strate-
gies you can use at test time. Throughout this chapter, you will review the structure of the science
exam and learn specific tips you can use to improve your score on the test. Read this chapter care-
fully, and then review your notes from the science section. When you are ready, move on to the practice ques-
tions that follow.

Multiple-Choice Questions
The good thing about multiple-choice questions is that the answer is right in front of you. All you need to do is
find it, or at least eliminate some of the clearly wrong choices.
At times, you may not be able to eliminate all four of the incorrect choices. But there is no penalty for guess-
ing on the GED. If you can eliminate one of the wrong choices, you will have a 25% chance of guessing correctly,
and that is still better than leaving it blank. If you can eliminate three choices, you have a 50% chance of getting
the question right.
When answering multiple-choice questions, make sure you have read the question carefully. Often, the ques-
tion will ask you to chose a statement that is NOT true or find an exception to the rule.
CHAPTER
Tips and
Strategies
for the GED
Science Exam
IN THIS chapter, you will briefly review some tips you can use on the
GED Science Exam. Several tips apply to other sections of the GED

as well.
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261
Even when you think you have found the correct
choice, quickly glance at the other choices to make sure
that no other choice is better or more specific. Also,
check whether one of the choices is “All of the above.”
You may well have picked out a correct statement, but if
the rest of the statements are also correct, the answer
needs to be, “All of the above.”

Types of Questions
Two types of questions appear on the GED—conceptual
understanding and problem solving.
Conceptual understanding questions require you to
read and understand the information provided or to
recall basic knowledge you have acquired through prior
schooling or everyday life. Read the question and infor-
mation provided along with it carefully. Often, a ques-
tion will ask you to restate what was already said or to
make a generalization about the facts presented in a pas-
sage. By reading carefully and making notes on a piece of
scratch paper as you go along, you increase your chances
of understanding the provided information correctly.
Problem-solving questions require you to apply what
you have read or learned. As you are studying for the
exam, when presented with a scientific fact, such as
“energy can be converted from one form to another,”
think about the situations in which that fact is apparent.
Think about a car—using the chemical energy in the fuel

causes the car to move and the engine to heat. Think
about how the fuel level decreases as the car moves.
Where is the fuel going? What is happening to the
exhaust gases? The principles of science are all around
you. By paying attention to them in your everyday life,
you will be better prepared to answer problem-solving
questions on the GED.

Reading and Understanding
Graphics
About half of all GED Science questions include graph-
ics. By becoming familiar with different types of graph-
ics and learning about their essential components, you
will be better prepared to answer GED Science questions
that contain graphical information.
When looking at a chart or a graph, look at the title or
caption first. This will give you an overview of what the
graphic is showing. Next, look at any legends or axis
labels provided. This will give you an idea of what vari-
ables are shown. Make a list of the variables. Once you
have done that, you can try to interpret the chart or
graph by noting any trends you may see. How is one vari-
able changing in response to the other? Next, you can
read the question and attempt to answer it. Here is more
specific information about graphics.
Charts
All charts are composed of rows (horizontal) and
columns (vertical). Entries in a single row of a chart usu-
ally have something in common, and so do entries in a
single column. Determine what the common elements

are when you try to answer the questions on the GED
Science Exam.
Graphs
Three common types of graphs are scatter plots, bar
graphs, and pie graphs. This section provides a brief
description of each.
Whenever a variable depends continuously on
another variable, this dependence can be visually repre-
sented in a scatter plot. An example includes a change in
a property (such as human population) as a function of
time. A scatter plot consists of the horizontal (x) axis, the
vertical (y) axis, and collected data points for variable y,
measured at variable x. The variable points are often
connected with a line or a curve. A graph often contains
a legend, especially if there is more than one data set or
more than one variable. A legend is a key for interpret-
ing the graph. Look at the sample graph above. The
essential elements of the graph—the x- and y-axes—are
labeled. The legend to the right of the graph shows that
dots are used to represent the variable points in data set 1,
Graph Title
100
120
140
80
60
40
20
0
0246810

data set 1
data set 2
y-axis
x-axis
– TIPS AND STRATEGIES FOR THE GED SCIENCE EXAM–
262
while squares are used to represent the variable points in
data set 2. If only one data set exists, the use of a legend
is not essential.
Bar graphs are similar to scatter plots. Both have a
variable y plotted against a variable x. However, in bar
graphs, data is represented by bars, rather than by points
connected with a line. Bar graphs are often used to indi-
cate an amount or level, as opposed to a continuous
change. Pie graphs are often used to show what percent-
age of a total is taken up by different components of that
whole.
Diagrams
Diagrams could be used to show a sequence of events,
a chemical or biological process, the setup of a science
experiment, a phenomenon, the relationship between
different events or beings, and so forth. When you see a
diagram, first determine its purpose. What is it trying
to illustrate? Then, look at the different labeled parts of
the diagram. What is their function? How are they
interrelated?

Reading and Understanding
Scientific Passages
When reading a scientific passage, the most important

thing is to focus on the big picture, or on the subject of
the passage. In many ways, the reading passages in the
science part of the GED are the same as the reading pas-
sages in other areas. One important difference is that sci-
ence passages may expose you to science jargon,
specialized vocabulary you may not be familiar with. Try
not to let new words throw you off. You may be able to
guess their meaning from the context. Even if you can’t,
keep reading. The questions following the passage may
not require you to understand that particular word.

Series of Questions Based on a
Passage or Graphic
On the GED, you will sometimes be asked more than one
question based on the same graphic or passage. When
this is the case, it is worth your while to invest a little
more time to understand the graphic or passage. Even if
you are unsure about the first one, try answering the
remaining questions—they may be easier for you.

Experiment Skills
Experiments should be designed and conducted in
accordance with the principles of the scientific method.
This means that the goal of the experiment should be
carefully formulated and the experiment should be set
up to yield factual results. Review the concepts of the sci-
entific method in Chapter 22 if the tips included in this
section are unfamiliar to you.
Setting Up an Experiment
Experiments should be set up to test one clearly formu-

lated and testable hypothesis. The number of variables
(things changing) in the experiment should be limited
and carefully controlled. If possible, experiments should
contain a control group. For example, if you were to
study the effect of a new soil supplement on house
plants, the soil supplement should not be used on a few
plants, which will comprise the control group. If there is
improvement in the growth of only the plants on which
the supplement was used, then there is strong indication
that the supplement increases the plant growth. If, how-
ever, the plants in the control group grow as much as the
plants on which the supplement was used, then the
causes of growth most likely are not linked to the sup-
plement. In this example, there would be two variables—
the use of the supplement and the plant growth.
How the supplement is administered and how plant
growth is measured would need to be carefully described
and controlled. For example, the scientist conducting the
experiment would need to decide whether the supple-
ment would be administered once, several times, or every
day throughout the experiment. The scientist would also
need to define what constitutes plant growth—the ver-
tical increase, the number of new leaves, the growth of
new branches and leaves, or some combination of these
factors. One choice is not necessarily better than the oth-
ers. Measuring the vertical growth wouldn’t necessarily
be worse than counting the number of new leaves. Sci-
entists must be consistent. If the number of leaves is
recorded one day on one plant, it should be recorded
every day on all the other plants in the experiment.

On the GED, you may be asked to pick out the best
design for an experiment. Before you look at the choices,
determine the important variables and what would make
a good control. Select the choice that contains these vari-
ables, that has the most logical experimental control, and
in which the variables not studied are held constant.
– TIPS AND STRATEGIES FOR THE GED SCIENCE EXAM–
263
Interpreting Others’ Results
In some GED questions, you will be asked to interpret
others’ results. You will need to make a generalization
about the results or draw a conclusion. Don’t base your
answer of what you believe is right. Base your answers on
the results provided. Look at the choices given. Some
could be inaccurate—if one part of the result doesn’t fit
the description in the choice, the choice is wrong (unless
words such as generally or in most cases make room for
exceptions). Make sure you don’t jump to conclusions. A
trend doesn’t always indicate a cause and effect relation-
ship. For example, every morning, your alarm clock goes
off, and every morning, you get hungry. However, the
alarm clock is not what is making you hungry. The two
events just happen to occur at the same time. Before you
conclude that there is a cause and effect relationship on
the GED, consider other conclusions, and then pick the
most logical one.
Analyzing Experimental Flaws
A common GED Science question requires you to ana-
lyze the flaws of an experiment. Experiments should be
based on the scientific method. Common experimental

flaws include:
■
not testing the hypothesis
■
having too many variables
■
unforeseen variables
■
lack of experimental control
■
jumping to conclusions
Applying Scientific Conclusions
What good is science if we don’t benefit from it? How
would the finding that keeping a laptop on your lap for
too long can damage your pelvic organs influence you?
You would not keep the laptop on your lap for too long,
right? Many questions on the GED require you to apply
a scientific conclusion, either to your personal life or to
global phenomena. These are almost always questions
from the problem-solving category. You are presented
with a fact in one context and asked to apply it in another
context. For example, if you read in a passage about dif-
ferent methods of determining the sides of the world in
nature without a compass, you could be asked which of
the methods would best work if you were in a particular
situation—lost on a cloudy night in a forest, on the
ocean on a clear day, etc. If necessary, as you are reading
information provided in the question, make quick dia-
grams and summarize the important concepts on a piece
of scrap paper. These strategies may help you visualize

the concepts or the given situation and could help you
make sense of the question.

Other Useful Skills
The more material you are exposed to, the easier it will
become to understand it. Reading about science and
applying science takes practice, just like riding a bike. At
first, you may be a bit clumsy with it, but if you stick with
it, you improve rapidly and it begins to click. To compre-
hend science better, read as much about science as you
can—in newspapers, magazines, and on the Internet.
Make sure you look at graphics, as well. As you are read-
ing, think about what the passage or graphic, is commu-
nicating to you. What are the possible applications of the
science concepts discussed? What can you conclude based
on the information given? What methods were used to
arrive at the facts presented? Is anything presented an
opinion or belief rather than a fact? Try to make up ques-
tions about the passage or graphic you read. Imagine that
you are making up the GED: What could you ask the stu-
dents? By anticipating the move of your opponent, you
are better prepared to respond to it.
– TIPS AND STRATEGIES FOR THE GED SCIENCE EXAM–
264

Directions
Read the questions carefully and choose the best answer for each question. Some questions may refer to a passage,
illustration, or graph. Be sure to answer every question; you will not be penalized for incorrect answers. Do not
spend too much time on any one question so you can be sure to complete all the questions in the allotted time.
Record your answers on the answer sheet provided on page 267. Make sure you mark the answer in the circle

that corresponds to the question.
Note: On the GED, you are not permitted to write in the test booklet. Make any notes or calculations on a sep-
arate piece of paper.
CHAPTER
GED Science
Practice
Questions
NOW IT’S time to put all that you have learned about science and
scientific inquiry into practice. In the following section, you will find 75
multiple-choice questions like those you will find on the GED Science
Exam.
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