Scientific Method
A world-wide system used
to help solve problems or
explain natural occurrences.
What is involved?

I. Making observations

II. Deciding on a problem or purpose to focus on

III. Stating a hypothesis

IV. Testing your hypothesis (experimenting)

V. Collecting and organizing data ( using tables)

VI. Analyzing relationships b/w data (using graphs)

VII. Drawing conclusions

VIII. Verifying the results
STEP 1: Make Your Observations

Just think to yourself, “What types of
things can be observed?”
 temperature,
volume, mass, height, color,
texture, taste, size, shape, movement …

Remember - Observations are:
 the
most important first step in science &
 continued throughout scientific studies.
Practicing Observations

What types of
things can you
observe in the
picture?
STEP 2:
Deciding the Problem or Purpose

Ask yourself, “What do I want to know
about __________ based on my
observations?”

Write your Problem or Purpose:


As a statement or
As a question
STEP 3: Making Your Hypothesis

What is a hypothesis?
A statement that gives a possible explanation to your
problem. (-an educated guess at the solution or what
the results will be)

Your Hypothesis should be testable!
 It must be observable &/or measurable

What is NOT testable with science?
 opinions, politics, morals, social issues…
 There must also be technology presentably
available to prove it!
Is it a Hypothesis?
Are the following testable? Why or why not?
1. Fish are happy when they swim.
2. Plants grow taller when fertilized.
3. It is wrong to hunt animals.
4. There is life in the next universe.
5. When a baby cries, he is hungry.
Writing the Hypothesis

Common format (but not always necessary):
If…, then…

You must clearly state both the:
WHAT you are going to test (independent variable)
 WHAT you are going to measure (dependent
variable).

NOTE: A hypothesis will state the cause and effect
in the experiment, as well as a prediction of what
your results will be.
Hypothesis Example
EXAMPLE:
Question: Would salt water effect the growth of
my plant?
Hypothesis:
If I water my plant with salt water, then the plant’s
growth will decrease.
-OR- I think salt water will decrease the growth
of my plant.
Practicing Writing
Testable Hypotheses
DIRECTIONS: Write a testable hypothesis for one
problem given below:
1. Would adding soap to a bubble solution
make more bubbles?
2. Do cooler temperatures affect how bacteria
multiply?
3. Will acid rain have an effect on the grass in
my yard?
STEP 4: Testing Your Hypothesis
(Experimenting)
All experiments contain many VARIABLES:
 Constant Variables
controls (kept the same)
 Changing Variables
independent vs. dependent
Looking back at the hypothesis you wrote, circle
the independent and underline the dependent
variables.

1. controls: brand of soap, water temperature,
agitation (swishing), water quality

2. controls: strain of bacteria, initial amount of
bacteria, type and amount of food, environment
other than temperature

3. controls: amount of water, type of grass,
season, soil
There are 2 groups in your experiment:
The control and the experimental groups.
 Both
groups will have the same controls!
 Only
in the experimental group will one
variable be changed from the control group.
 You
CANNOT change or test more than one
variable at a time! You wouldn’t know which
variable caused something to happen!
STEP 5: Collecting Data
Create a table of the data. Don’t
forget to put units in the headings
and add a specific title.
Analysis of Data
Graphs provide visual comparison of data
You must make inferences (logical connections)
and predict trends (natural tendencies).
STEP 7: Drawing Conclusions
 Did
your results agree with your
hypothesis (Is it valid or supported)?
We do not say “proven.”
 Include
made.
errors that may have been
STEP 8: Verify Results

Experiments need to be repeated many times to limit the
amount of error or bias.

When results are consistent, THEORIES are created to
explain a range of observations and findings.
EX: Big Bang Theory, Theory of relativity (Einstein), Cell
Theory, Theory of Evolution

LAWS, however, are fixed statements of fact that do not
explain the “why.” Describes a single action!
EX: Law of Gravity, Newton’s Laws
Hypothesis Becomes a Theory


In short, a Hypothesis becomes a theory only
when many scientists test the hypothesis and
produce the same result.
Once a theory is produced, it must also be
falsifiable, which means it is capable of being
modified based on new evidence.