DISTINGUISHING FACTS FROM HYPOTHESES
In 1984, scientists found pieces of a meteor that had slammed into Antarctica.
*In plant cells, chlorophyll is contained in structures called chloroplasts.
*In plant cells, chlorophyll is contained in structures called chloroplasts.
What do these statements have in common? Each one is a fact, a statement that can be proven. Even though they contain different information, each statement can be validated. Readers can verify facts by observation or by checking in reliable sources such as textbooks, reference books, and periodicals.
How are the following three statements different from the previous ones?
Scientists speculate that the solar system was formed about 6 billion years ago from a swirling cloud of gas and dust.
*Scientists surmise that the first step toward life on Earth may have been the formation of organic molecules.
*In 1924, Russian biochemist Alexander Oparin hypothesized that energy in ultraviolet radiation and lightning stimulated chemical reactions in the ancient atmosphere.
Each of these statements describes a hypothesis. A hypothesis is a possible explanation for an event or a set of observations. Scientists form hypotheses to explain many things that they observe. In many instances, scientists create experiments to test their hypotheses. However, this is not always practical or even possible.
Hypotheses are not facts. Nevertheless, hypotheses aren't wild guesses, either! Scientific hypotheses are based on many reliable sources, including personal observations, investigations, and experiments.
Distinguishing between facts and hypotheses is an important part of critical thinking. It is a crucial reading skill because it enables you to make judgments about what you read.
WHAT TO LOOK FOR
- Facts
A fact is a piece of information. It is not an explanation. As you read, ask yourself if you could get this information from observations or reference sources. Remember, if you can measure it, count it, or look it up, it's a fact, not a hypothesis.
- Hypotheses
Look for explanations, reasons, or predictions. Hypotheses are often stated with signal words or phrases, such as scientists believe, biochemists hypothesize, ecologists predict.
TRY IT
Identify the fact and hypothesis in the following sentences
from STUDYING LIFE'S ORIGINS on page 256.
Until a few hundred years ago, most people believed that life
could arise from nonliving matter. According to this belief,
called spontaneous generation, living things can spring from
nonliving materials when invisible "active principles"
are present.
Click here to check your answers to TRY IT!
To practice what you've just learned, go to Worksheet 3.1
To learn about another reading strategy, go to Reading Strategy 3.2.
Reading Strategy 3.1 | Worksheet
3.1
Reading Strategy 3.2 | Worksheet
3.2
Copyright © 2008 by Pearson Education, Inc. publishing as Pearson Prentice Hall. All rights reserved.
Privacy Statement, Terms of Use, Permissions