Everything you need to know
to successfully use
THE SCIENTIFIC
METHOD
First of all – WHY bother?
The SM helps you organize your work.
The SM helps you be able to repeat your work.
The SM helps OTHERS be able to repeat your work.
The SM helps you be sure
to not forget anything.
The SM helps make sure that you have a FAIR test.
So where to begin – the
RESEARCH QUESTION
The RESEARCH QUESTION defines what you are doing –
and what is being tested.
It is written:
What is the effect of ….. On …..?
(a question ALWAYS ends in a ?)
Now you know what you are testing and what you
are measuring because . . .
The research question actually says:
What is the effect of
the INDEPENDENT VARIABLE
on the DEPENDENT VARIABLE?
The Independent Variable (IV) is what you are
testing – what YOU are changing in the test.
The Dependent Variable (DV) is what you
are MEASURING – and at BRMS you need
to measure in numbers!!
A good scientist always THINKS
about what he or she is doing, so the
next element is the HYPOTHESIS –
an educated guess.
You don’t need to do a lot of research to come up with
your educated guess – you have to THINK about what
you are doing and what might happen when you change
the independent variable.
A hypothesis CANNOT be considered wrong – but it
can be stated incorrectly.
A hypothesis is worded:
I think IF……… THEN because ………
So now that you’ve given that some
thought – it’s time to make sure that
you CAN do the experiment.
If you were baking chocolate chip cookies
you would make sure that you have enough
of each ingredient BEFORE you began the
cookies – no point in getting started and not
having enough chocolate chips!!
Now you determine your list of MATERIALS –and
you must be VERY SPECIFIC – tell us EXACTLY what
you need to do this experiment.
Your materials are written in list form
to make it easier to read them.
You also want to be sure that you
understand what you are finding out – you
need a CONTROL to be sure of what your
experiment proves.
The CONTROL is what you compare your results to.
If you want to know what is the effect of different
exercises (IV) on heart rate (DV) your control is the
heart rate BEFORE you exercise. Think about 2 people
exercising and each one raising their heart rate to 150
beats per minute. If one person’s heart rate STARTED at
100 that means that their exercise raised their heart rate
50 beats per minute. If another one started at 145 beats
per minute their exercise only raised their heart rate 5
beats per minute. That’s a big difference.
Which exercise had the most effect on the heart rates By comparing to the control you can tell.
When performing an experiment you want to make
sure that you have a FAIR and ACCURATE test.
By keeping everything but the
Independent Variable CONSTANT
you can be sure that your test is fair.
If you are testing the effect of different exercises you would
want to make sure that you are testing the same age or sex
of people, that they are in the same ‘shape’, that they are in
the same environment, that they are wearing the same
clothes and that the experiments are preformed the SAME
WAY.
You want to make sure that the control is clearly met before
you do more exercises – or else your test is not fair.
Once you have thought through ALL of those first steps:
Research Question
Hypothesis
Independent and Dependent Variables
Control
Constants
1.
Materials
2.
3.
4.
5.
6.
You can decide HOW you will test and
measure – and write out everything in
your PROCEDURE.
Procedures are written in list form – with numbers to help you
follow the steps.
BE SPECIFIC – someone else must be able to repeat your
experiment EXACTLY by using your procedure.
Your last step should always be to REPEAT and AVERAGE your
results. If you can’t repeat you need to do LOTS of trials to get a
fair test.
Now perform your test – and MEASURE your results.
And, organize and record your results in a
DATA TABLE
Data Tables have a TITLE – the same as
your experiment!!!
They have HEADINGS and UNITS that
show what you learned.
The CONTROL is always in the first
row – that makes it easy to compare
things to it.
Make sure that you show all of your
trials and the final average of your
results
Let’s look at a sample DATA TABLE:
(Your hypothesis was that jumping jacks will raise the heart rate more than other exercises.)
The effect of different exercises on heart rate.
(The title can be a sentence.)
Exercise
Resting heart
rate – beats
per minute
Heart rate after
exercise – beats per
minute
CHANGE in
heart rate –
beats per minute
Jumping jacks
120
165
45
1 mile jog
115
165
50
50 sit-ups
115
130
15
This table is missing a very important element
– you must REPEAT your experiment and show the average of your trials.
Check out the next slide for a more complete Data Table.
The effect of different exercises on heart rate.
Reported as beats per minute.
Exercise
Trial 1 –
Trial 1 –
Trial 1
resting
heart rate change
heart rate after
in heart
exercise
rate
Trial 2 –
Trial 2 –
resting
heart rate
heart rate after
exercise
Trial 2
change
in heart
rate
Average
change
in heart
rate
The important thing to see here are the trials and the average results.
It’s the average results that you will use as we continue.
Data Tables are nice, but GRAPHS can SHOW your results in an
easier to read way. Now you take your data and present it in a
graph. You always present your AVERAGE results if you could do
repeat trials – or else present all of the data you have.
Graphs need the same title as your Data Table. They type of graph
you use depends on what you measured – for example, a line graph
shows change over time, a bar graph shows final results.
Now that you have tested, measured, compared, and presented
your data – WHAT DO YOU DO?
This is the time when you DRAW A CONCLUSION – you look at your
results and try to determine WHAT DID YOU FIND OUT?
Your conclusion is written with 2 parts:
WHAT DID I LEARN?
HOW DOES THIS COMPARE TO MY HYPOTHESIS?
You may also write about what you would do differently
if you did the experiment again, and what others should
know about doing the experiment.
Now that you have tested, measured, compared, and presented
your data – WHAT DO YOU DO?
This is the time when you DRAW A CONCLUSION – you look at your
results and try to determine WHAT DID YOU FIND OUT?
Your conclusion is written with 2 parts:
WHAT DID I LEARN?
HOW DOES THIS COMPARE TO MY HYPOTHESIS?
You may also write about what you would do differently
if you did the experiment again, and what others should
know about doing the experiment.