The Scientific Method
The Scientific Method
The Scientific Method is a series of steps
used answer a question or solve a
problem
- There are 5 main steps
•
•
•
•
•
Step
Step
Step
Step
Step
1: Ask a Question
2: Form a hypothesis
3: Perform experiment to test hypothesis
4: Analyze results
5: Draw conclusions
** Sometimes, 2 extra steps are included :
 step 2: collect data and communicate results
 last step: communicate results
See Lab Safety Package pg. 7-8
The Hypothesis
Hypothesis: an educated guess or
prediction. It must be testable.
We will write our hypothesis using an
“if, then, because” statement:
If ____independent variable______
then__dependent variable_______
because ___scientific explanation___.
Example:
Independent Variable:
The amount of food I feed my cat
Dependent Variable
My cat’s weight
If ___________________________
then _________________________
because _______________________.
Remember
Try to use INCREASE and DECREASE
in your hypothesis!
Ex. IF I increase the amount of food I give
my cat, THEN she will increase her weight,
BECAUSE there will be an increase in
calories.
Now Try it on Your Own!
‘Writing a Good Hypothesis”
Just ‘plug and chug’ in your variables!
Refer to Handout:
Writing a good hypothesis.
The experiment:
Writing Procedures
• Let’s brainstorm a few simple tasks
that we do on a daily basis.
• On your own, write a detailed
procedure for one of the tasks on
our list
The experiment:
Identifying Variables
There are 2 main types of variables:
Independent Variable: The variable that is
changed/decided upon by the scientist;
Dependent Variable: The variable that might
change because of what the scientist is
doing– what is being measured
Remember!
Your hypothesis can TELL you what
your variables are!
Ex. If I drink Mountain Dew before
bed, then I will not sleep very much
because it is high in caffeine.
IV: Drinking Mountain Dew
DV: the amount of sleep
Practice
Identify the variables in the hypothesis
statement:
If I brush my cat more, then there will
be less fur on my couch because it
will be gathered by the brush.
IV: ______________________
DV: ______________________
Now read the following experiment and
identify the independent and dependent
variables
Elizabeth wanted to test if temperature affected
how fast milk goes bad and curdles. She left milk
in a room temperature closet, a fridge, and on the
counter in direct sunlight. She then measured
how rotten the milk was after 10 days.
IV: ____________________________________
DV: ____________________________________
Examples:
DEPENDENT
INDEPENDENT
Cell phone bill
Minutes used
How far you can drive
The amount of gas you have
How much money you earn
The hours you work
Cost of a speeding ticket
How many kilometers you went
over the speed limit
Time it takes to drive
somewhere
How fast you drive
Result of a football game
Who scores more points
How much air conditioning you
use
Temperature
Total calories and fat
Number of burgers you had
YOUR TURN TO PRACTICE!!! Refer to handouts
Independent and Dependant Variables
A Variable Way to Practice Variables
Constant
Constant: something that scientist make
sure is the same throughout the
experiment
Ex. Watering the plants the same amount of
water or making sure you are using the
same measure tools every time.
Control
Control: The part of the experiment
that the scientist doesn’t change
Ex. One plant will be planted in regular
soil while the other plants will get
planted in soil and fed with different
types of fertilizer.
YOUR TURN!
Identify the controls and variables (Simpson
worksheet)
The experiment:
Making Observations
• While conducting your
experiment(s), you will need to
make observations.
• Whenever possible, you should
make a table to organize your
collected data.
• There are 2 types of observations:
- Quantitative and Qualitative
- What is the difference?
The Analysis
• This is the most important part of
your experiment!
• This section will be taught to you
separately  Graphing
The Conclusion
• The conclusion should state whether your tested
hypothesis was correct or incorrect.
• Even if it was incorrect, what matters is that you try
to explain why scientifically.
• You need to make statements based on your analysis
(looking at the graphs).
• You also need to include sources of error. (Human:
miscalculations, reading scales, Mechanical:
instrumental- scale or thermometer isn’t accurate)