THE SCIENTIFIC METHOD
Key Idea #1 : The central (main) purpose of
scientific inquiry is to develop explanations
of natural phenomena in a continuing and
creative process.
Key Idea #2: Beyond the use of reasoning
and consensus, scientific inquiry involves
the testing of proposed explanations
involving the use of conventional techniques
and procedures, and usually requires
considerable ingenuity.
Key Idea #3: The observations made while
testing proposed explanations, when
analyzed using conventional and invented
methods, provide new insight into natural
phenomena.
INTRODUCTION
Science relies on logic and creativity. Science is both a body of knowledge and a
way of knowing -- an intellectual and social process that applies human intelligence
to explaining how the world works. Scientific explanations are developed using both
observation (evidence) and what people already know about the world (knowledge).
All scientific explanations are tentative and subject to change. Good science involves
questioning, observing, inferring, experimenting, finding evidence, collecting and
organizing data, drawing valid conclusions, and undergoing peer review.
Understanding the scientific view of the natural world is an essential part of
personal, societal, and ethical decision making. Scientific literacy involves
internalizing the scientific critical attitude so that it can be applied in everyday life,
particularly in relation to health, commercial, and technological claims.
Scientists work in a methodical manner to solve the mysteries of the universe.
They gather data using a variety of tools and instruments that have been carefully
calibrated. They record data so that conclusions can be drawn and patterns can be
recognized.
THE SCIENTIFIC METHOD
UNIT OUTLINE
Key Concepts
Part 1. Collecting and Organizing Data
* In science, data refers to the results of trials, or
tests, completed during experiments.
* Data can be organized in a variety of ways
including charts, tables, diagrams, equations,
matrices, and graphs.
* Scientists use the data collected in experiments to
make inferences, predictions, and conclusions.
* The two main kinds of graphs scientists use to
organize data are line graphs and bar graphs.
* A line graph is used to show the relationship
between the INDEPENDENT VARIABLE (X) and
the DEPENDENT VARIABLE (Y). The title of a
line graph follows this formula: “The Effect of X
on Y.”
* Scientific graphs DO NOT use breakers!!
* The independent variable is the factor in an
experiment that you purposely change, while the
dependent variable responds to that change. For
example, if you give a plant some fertilizer
(independent variable), the height of the plant will
be affected (dependent variable.)
* Graphs make patterns and trends easier to
identify.
* Bar graphs are used to compare data. For
example, a bar graph can compare the heart rate of
someone before and after having consumed
caffeine. Bar graphs can also be used to compare
the amount of materials in a sample, such as colors
of candies in a package.
* Numbered scales on a graph must be in equal
increments, without any breaks.
Part 2. The Scientific Method
* The scientific method consists of a series of
logical steps aimed at establishing facts about
an object, event, or process. In other words,
the scientific method is a step-by-step method
to solve problems and answer questions.
* The scientific method usually follows these
basic steps: 1) Ask a question or state a
problem, 2) Do some research to see what is
already known, 3) Form a hypothesis, 4)
Design a controlled experiment, 5) Make
observations, collect and organize data, 6)
Analyze the data collected so you can state a
conclusion.
* A hypothesis is a possible answer or solution
to the problem. It is best written in as an
“If...then,,,” statement. For example, “If plants
receive fertilizer, then they will grow taller.”
* A controlled experiment is an an experiment
set up in duplicate and only one variable is
changed.
* The factor that is changed is called the
independent variable, or manipulated
variable. All other factors in both groups
must remain the same.
* The factor that responds to the independent
variable is called the dependent variable, or
responding variable.
* To make the results of an experiment more
reliable (valid), scientists must conduct the
experiment many times with similar results.
NOTE: VALID is NOT same as accurate!
* The experimental group is the group in an
experiment in which the independent variable
is changed. The control group has all factors
stay the same and is used as a standard for
comparison.
* In experiments involving humans, the control
group often receives a placebo, or sugar pill,
so that they do not know they are part of the
control group. This will help to reduce the
effects of bias, which is a tendency to prejudge the results based on what they think
should happen.
VOCABULARY
data! !
!
line graph! !
bar graph! !
x-axis! !
y-axis! !
!
scientific method!
controlled experiment
manipulated variable
hypothesis
valid/reliable
independent variable
dependent variable
experimental group
control group
placebo
bias