THE SCIENTIFIC METHOD
SECTION HEADINGS
Overview











Scientific Methods and
Observations




MAIN IDEA/KEY CONCEPTS
1. Describe a scientific method.
2. Explain how it is used to answer questions.
3. Explain how a hypothesis is formed and tested.
4. Identify methods to analyze data.
5. Explain how a conclusion can support or
disprove (refute) a hypothesis.
6. List methods of communicating data.
TABBS
T – turn it around
A – answer it
B – back it up
B – back it up again
S – summarize
Scientific methods are the ways scientists solve
problems and answer questions by following specific
series of steps. At each step observations are made
about what is going on, and what is changing.
Scientists don`t always use every single step of the
scientific method every single time they conduct an
experiment. BUT they do always start by making
observations.

These observations lead to questions.
KEY TERMS WITH DEFINITIONS
Scientific Method
Observations
Problem
Hypothesis
Controlled Experiment
Independent Variable
Dependent Variable
Controls
Constants
Procedure
Data
Conclusion
Validity
Additional terms: subjective, objective, qualitative,
quantitative, opinion, fact, support, refute, sources
of error
Observation – information collected by using the
five senses, i.e. vision, hearing, taste, smell, touch.
Subjective – an observation based on the opinion
of the observer; not necessarily a fact.
Objective – Observation that is true and factual for
everyone; can be verified and proven
Quantitative – Data that is measurable in
numbers; i.e. temperature, time, height, weight,
mass, volume, density, etc.
Qualitative – Data that is factual, but can’t be
measured in numbers; i.e. color, malleability,
conductivity, ductility, texture, state, solubility,
reactivity etc.
THE SCIENTIFIC METHOD
Problem
Forming a hypothesis
Testing the Hypothesis
The Problem Statement is based on questions asked
after a series of initial observations and some
background research. Describe the problem that you
are trying to solve. Provide some explanation into
the background or history of the problem.
Problem - The idea the scientist is investigating in
an experiment. The question the scientist is trying
to answer; the solution he is trying to find.
Why are you conducting the experiment (rationale),
and what do you hope to learn (purpose)?
(TABBS)
“The application(s) to real life solution(s) is/are…”
A hypothesis is a possible answer to a question; a
prediction; an educated guess. A good hypothesis is
testable. (TABBS)
Sentence starters – “The reason(s) for conducting
this experiment is/are ….”
“We hope to learn who – what – when – where –
why – how -…”
Hypothesis - A testable idea or explanation that
leads to a scientific explanation; it uses “if”,
“then”, and “because.”
Good example: “I predict that if I exercise then my
pulse will speed up because my heart rate will
increase.”
Bad example: “Do these jeans make me look fat?”
Sentence starter -“I predict that if we change
…(IV)… then the result will be …(DV)… because
(Scientific Principle)”
After you form a hypothesis you must test it through
a controlled experiment. This compares the results
from the control (group) with the results from the
tested (group). The groups are the same other than a
variable.
Independent Variable (I.V.) - The change
manipulated by the scientist; the cause; the action
taken.
Procedure: A kind of ‘recipe’ for the experiment
that so clear and specific that it can be repeated by
someone else.
First list all the materials, ingredients, tools, and
measurements that will be needed.
Follow this with a detailed step by step set of
directions for the experiment.
SOMETIMES A CONTROLLED
EXPERIMENT IS NOT POSSIBLE.
Dependent Variable (D.V.) - The change that
takes place as a result of the Independent Variable;
the effect; the reaction.
Control - The group not affected by a change OR
the Independent Variable BEFORE the first
change. This serves as a starting point or a baseline
measurement.
Constants - Those things that must NEVER
change during the course of the experiment such as
the tools used to measure, the way they change is
measured, or the surrounding environment in the
lab.
THE SCIENTIFIC METHOD
Data
All the information collected during the course of the
experiment must be collected in a logical and
consistent manner. Using data tables helps organize
the results. (TABBS)
This information should then be able to be
transformed into a graph so that trends can be
observed.
Drawing conclusions
Make sure all charts / tables / diagrams / drawings /
graphs are well labeled and neat. Use a ruler and
graph paper, or a graphing program. (TABBS)
Analyze the results and determine whether or not
they support the hypothesis. The conclusion begins
by restating the hypothesis, and then stating whether
it was supported or refuted by the data. Refer back
to specific examples in the data, and explain any
trends. Include any qualitative observations that
may have affected the results.
(TABBS)
Explain if the experiment was well carried out and
valuable; i.e. was it a fair test, were there at least
three trials for each change in the independent
variable, were all measurements consistent, were the
constants maintained? State if the experiment was
NOTE: AN EXPERIMENT
completely valid, mostly valid, or invalid. Include
CAN REFUTE YOUR
HYPOTHESIS AND STILL BE possible sources of error. Did the experiment
generate any new ideas or questions, or cause you to
VALID.
come up with a new hypothesis? State how you
(TABBS)
would improve the experiment if you were to do it
again.
Validity
Data - Any pieces of information acquired through
observations or experiments.
Table - A chart of data showing the Independent
Variable changes and the Dependent Variable
Changes
Graph - Diagram comparing I.V. and D.V. Must
have an X axis and a Y axis – I.V. is on the X Axis
and D.V. is on the Y Axis. Must include a title
comparing I.V. to D.V.; each axis must be labeled
and include the measurable units such as seconds,
minutes, grams, meters etc.; must also include a
key.
Support – to agree with, or prove to be accurate
or correct
Refute - to disagree with, or to prove to be
inaccurate or incorrect
Sentence starters – “We predicted that if we
changed …(IV)… then this result (DV) would
occur … because of ….” “Our hypothesis was
supported/refuted by the data in these ways…”
“The graph shows that in fact….”
“In addition we observed ...” “Therefore our
hypothesis was supported/refuted by the data.”
Sources of Error – Anything that may have
influenced the accuracy of the data, including
inconsistent measurements, accidents, changes in
the constants, mistakes, not doing enough trials,
not having enough controls or a big enough control
group, etc. Sentence starters – “Our experiment
was completely valid/mostly valid/ invalid
because… “I did/did not have enough data in this
lab …” “If I were to do this over again, I would
…” “This generated many questions. I would like
to know…”