Transcript Scientific Method:

Scientific Method:
Science is ultimately based on observation
(perceiving objects or events using one of the
five senses)
Observations often lead to questions ---> which
lead to experiments to answer the questions.
The common steps that biologists and other
scientists use to gather information and
answer questions
Scientific Method
1. Ask a question: Scientists begin by
identifying a problem and asking a
question to try and find an answer
2. Research
3. Formulate a hypothesis:
an explanation for a question or a problem that
can be formally tested
• A hypothesis is not a random guess.
•
A hypothesis can never be proven only shown
to be valid; however it can be proven false.
Hypothesis
Examples
Good
1. Plants will grow taller when given Miracle
Grow.
2. Hermit crabs choose colorful shells over drab
shells.
Bad
1. Plants will grow better when given Miracle
Grow.
2. Will hermit crabs like colorful shells? NEVER
POSE AS A QUESTION!
Scientific Method
4. Design a controlled experiment to test the
hypothesis
What is a controlled experiment?
•
In a controlled experiment, only one condition
is changed at a time.
•
All variables are kept constant except the
one you are testing
Setting up a test in duplicate- involves two
groups: the control group and the
experimental group
What is a controlled experiment?
The control is the group in which all
conditions are kept the same. The
control is a “reference point” for
comparison
 The experimental group is the test group,
in which all conditions are kept the same
except for the single condition being
tested.
Designing an experiment
• In a controlled experiment, only one
condition is changed at a time.
The condition in an experiment that is
changed is the independent variable
~What you change/manipulate
Designing an experiment
While changing the independent variable,
the scientist observes or measures a
second condition that results from the
change
This condition is the dependent variable
–What is measured
Designing an experiment
Formulate a PROCEDURE
Replicate
Sample size (large enough)
5. Analyze & Collect data
– A scientist carefully collects and organizes
data from the experiment. Data should always
be presented in a neat fashion, usually tables
or graphs.
Designing an experiment
6. Draw a Conclusion:
Based on the data, a scientist then determines
whether the hypothesis was supported or
refuted.
7. Report your results.
Everything I just told you was a lie…..
 Scientists do not follow a rigid procedure
list called the scientific method
 The majority of the steps are followed, but
not necessarily in the same order
Theory
Theory is an explanation for natural events
that is based on a large number of
observations.