Scientific Methods Explained

Unit 1 Lesson 3 Scientific Investigations
Copyright © Houghton Mifflin Harcourt Publishing Company

Indiana Standards
• NOS 8.1 Make predictions and develop testable
questions based on research and prior knowledge.
• NOS 8.2 Plan and carry out investigations as a
class, in small groups or independently often over
a period of several class lessons.
• NOS 8.3 Collect quantitative data with
appropriate tools or technologies and use
appropriate units to label numerical data.

Indiana Standards
• NOS 8.4 Incorporate variables that can be
changed, measured or controlled.
• NOS 8.5 Use the principles of accuracy and
precision when making measurement.
• NOS 8.6 Test predictions with multiple trials.
• NOS 8.7 Keep accurate records in a notebook
during investigations.

Indiana Standards
• NOS 8.8 Analyze data, using appropriate
mathematical manipulation as required, and use it
to identify patterns and make inferences based on
these patterns.
• NOS 8.9 Evaluate possible causes for differing
results (valid data).
• NOS 8.10 Compare the results of an experiment
with the prediction.

Testing, Testing, 1, 2, 3
What are some parts that make up
scientific investigations?
• Scientists investigate the natural world through
experiments and observations.
• An experiment is an organized procedure to
study something under controlled conditions.
• Observation is the process of obtaining
information by using the senses.

• Scientific investigations may also involve the use
of models.
• A model is a representation of an object or
system.

• A testable idea or explanation that leads to
scientific investigation is called a hypothesis.
• A scientist may think of a hypothesis after making
observations or after reading findings from other
scientists’ investigations.
• Hypotheses must be carefully constructed so they
can be tested in a practical and meaningful way.

• If an investigation does not support a hypothesis,
it is still useful.
• The information from the investigation can help
scientists form a better hypothesis.
• Scientists may go through many cycles of testing
and analysis before they arrive at a hypothesis
that is supported.

• A variable is any factor that can change in a
scientific investigation.
• An independent variable is the factor that is
deliberately manipulated.
• A dependent variable changes as a result of
manipulation of one or more independent
variables.

• Data are information gathered by observation or
experimentation that can be used in calculating or
reasoning.
• This information may be anything that a scientist
perceives through the senses or detects using
instruments.
• During their investigations, scientists record all
their observations, setup, and procedures so that
they will not forget anything.

• Scientists analyze data to determine the
relationship between the independent and
dependent variables in an investigation.
• Then they draw conclusions about whether the
data support the investigation’s hypothesis.

Many Methods
What are some scientific methods?
• Scientists do not always use the same steps or
same order of steps in every investigation.
• They may even repeat some steps.

• Consider one possible path that a scientist might
follow while conducting an experiment.
• First, the scientist clearly and precisely defines the
problem or question that needs to be answered.
• Next, the scientist forms a hypothesis and makes
predictions about what will happen in the
investigation.

• To test the hypothesis, the investigation must be
carefully planned, taking into account the
materials and equipment needed.
• The scientist must also decide how the
independent variable will change and identify
other variables that will be controlled.

• The scientist must also determine how the results
of the experiment will be measured.
• The data collected in an investigation must be
recorded and properly organized.
• After the data are collected, the scientist may
analyze them and draw conclusions about the
results.

Life Lessons
How are scientific methods used?
• Science is an ongoing process, as scientific
investigations provide evidence that can either
support or contradict a hypothesis.
• A hypothesis can be replaced by a new or
modified hypothesis after further investigation.
• Thus, scientists are always prepared to modify
their understandings of the natural world.

How are scientific methods used?
• Scientific methods are used in physical, life, and
earth sciences.
• Scientists carefully choose the setting for an
investigation, such as the field or a laboratory.
• Scientists may use models when studying things
that are very large, small, or complex.

High Quality
What are some characteristics of good
• Good scientific investigations share some
important characteristics.
• Scientific observations should be well documented
and have supporting evidence.
• In an experiment, the variables should be
controlled as much as possible.

• Experiments should be repeated multiple times by
the original investigator.
• All scientific investigations should be replicated by
scientists not involved with the original work.
• Before publishing a study, scientific journals ask
other scientists to review the article. This is called
peer review.

How can you evaluate the quality of
scientific information?
• The most reliable scientific information is
published in scientific journals, but it is often
difficult to understand.
• Reliable books are written by scientists and others
who are knowledgeable about a particular field.
• Reliable Internet sources are government and
academic web pages. Commercial web pages are
often unreliable because they are trying to sell
something.

Scientific Methods Explained

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