Scientific Method
• A way to
understand
CAUSE AND
EFFECT in the
natural world
Scientific Method
Step 1: OBSERVE
Step 2: ASK A QUESTION
Step 3: RESEARCH
Step 4: MAKE A HYPOTHESIS
Step 5: TEST HYPOTHESIS
Step 6: CONCLUSION
Scientific Method:
Step 1 - Observation
• Based on your 5
SENSES
Seeing
Hearing
Smelling
Touching
Tasting
Scientific Method:
Step 2 -Ask a Question
• Question must be
‘testable’ using a
simple, direct
experiment
Scientific Method:
Step 3 – Research
• Look up everything
that is already
known. Read
papers published in
journals/books
/scientific literature
Scientific Method:
Step 4 : Hypothesis = Educated Guess
1. If dependent variable - is related
to independent variable,
2. Then - predict how dependent
variable will respond
3. When - independent variable is
changed by you
‘If-then-when statement’
Scientific Method:
Step 4 : Hypothesis = Educated Guess
• Background: Red Bull ads
claim to increase
concentration
• Ques: Can Drinking Red
Bull before a test improve
performance ?
• Identify variables
(anything that changes)
• Number of red bull drinks
and performance on test
• Independent variable and
dependent variable
Scientific Method:
Step 4 : Hypothesis = Educated Guess
-If performance on test is
1. If dependent variable - is
related to consumption of
related to independent
red bull energy drink,
variable,
2. Then - predict how
-Then average test score of
dependent variable will
students in AP Biology
respond
class will increase
3. When - independent
-When red bull drink is
variable is changed by
consumed 15 minutes
you
before the test
- ‘If-then-when hypothesis
statement’
Scientific Method:
Step 5a– Planning the Experiment
Experimental Design :
A. Variables (3 types)
B. Control Group/Setup
C. Experimental Group/Setup
Scientific Method:
Step 5a – Planning the Experiment
Experimental Design :
A.Variables – anything that can change in an experiment
- Independent Variable: anything that you change/manipulate
in an experiment (number of red bull drinks)
- Dependent Variable: anything that you measure as the
‘response’ to the change you made (average test score)
- Controlled Variables: anything that you would keep the same
in all experimental setups
- such as time when drink was consumed, other types of
stimulants the student has, test environment….
Scientific Method:
Step 5a – Planning the Experiment
Control group/setup: does not
have the independent variable
Group without
red bull
Experimental setup: has the
independent variable
Group with red
bull
Scientific Method:
Step 5b –Data Collection + Analysis
TABLES
GRAPHS
Scientific Method:
Step 6 – Conclusion
Did your results support hypothesis?
 why or why not?
interpretation of your data
did you run many trials?
what was your sample size?
sources of errors
changes you would make