Transcript A Process of Inquiry

Scientific Inquiry
and the
Scientific
Method
The Way Cool
Way
Science is Done
What is Science?
Science is a
process of inquiry.
It's a way of knowing.
That’s great,
but HOW ?!
“A Process of Inquiry”
Process = a series of logical steps
Inquiry = an examination into facts
or principles; a systematic
investigation
How is this done?
Thinking like a scientist
Observing – becoming aware of
something by using our senses
Let's say you have been hired by a local dentist to do a study on local candy eating
habits in the neighborhoods around his office. You can go about gathering data in
one of two ways, through direct observation, or indirect observation.
Direct observations – you are looking at an actual behavior or occurrence of some
event.
Example – you observe customers in a store and count how many
bags of candy they purchase.
Indirect observations – you observe the results of a certain behavior or
occurrence of an event.
Example – you look through trash cans on garbage day to see how
many empty candy bags are in each trash bin.
Thinking like a scientist
Qualitative observations – these are descriptions of
what we observe.
For example, it is hot outside today.
(think of the stem for “qualitative” - “quality”)
Quantitative Observations - these are measurements of what we observed.
For example, it is 90 degrees Fahrenheit outside today.
(think of the stem for “quantitative” - “quantity”)
Quantitative observations or measurements should be as
precise and accurate as possible.
Precision = how exact the measurement is.
Accuracy = how correct a measurement is.
Thinking like a scientist
Inference – an explanation of an observation,
a conclusion based on evidence or premises
Remember the ice cube experiment from our scientific method video?
The girl inferred that because the Styrofoam felt warmer, it would melt
the ice faster than the wood or aluminum.
Was her inference correct?
An inference is a logical conclusion based on facts and prior
knowledge, but it is not necessarily factual!
Ice melting faster on aluminum pan = an anomaly
The inference led the girl in the video to think one way,
but her experiment produced a very different outcome.
Result? More questions.
The Scientific
Method
The Scientific Method
It all begins with a question
about something you observe.
Ask Question
“How…?”
“What…?”
“When…?”
“Who…?”
“Which…?”
“Why…?”
“Where…?”
In order for the scientific method to answer your question, it
must be about something you can measure, preferably with
a number.
The Scientific Method
Don’t reinvent the wheel.
Research your topic to find out
Do background
research
what others have already done.
Research will help you avoid mistakes of
the past, and may help you refine your
original question and hypothesis, as well
as helping you structure your experiment
for the best possible results.
The Scientific Method
This is where you state what
you think will happen. Your
Construct
Hypothesis
hypothesis should be an
“if…then…” statement
(“cause and effect” )
“If I do this (cause), then this will happen (effect).
Your hypothesis should be measurable, and it should
help you answer your original question.
The Scientific Method
Your experiment will determine
whether your hypothesis is true
or false. It should be a fair test.
Test with an
Experiment
You make it fair by changing only
one variable at a time.
You should also repeat your
experiments several times to
make sure that the first results
you got were not due to
chance.
The Scientific Method
Claims & Evidence
After experiment is complete, compile
your data and analyze it to see if you
can support your claims with evidence.
Hypothesis
was correct
Go to
next step
Draw Conclusions
Hypothesis
was incorrect
Determine why,
revise hypothesis or
revise experiment,
repeat experiment
The Scientific Method
Once your work is
complete, write up your
experiment in the proper
format.
Report Results
In our case, that will
be a lab report.
We will discuss
how to write the
lab report later.
Experimental Design
Variables – the nuts and bolts of your experiment
Remember your hypothesis? It said
“If I do this, then that will happen.”
The “this” is a variable that you will change.
The “that” is a variable that changes due to the change of “this.”
Confused?
Let’s give them more proper names – independent, dependent,
and control variables – and take a look at each one.
Experimental Design
Variables 101
Independent variables - When you design your experiment,
you will want to change only one variable, and then observe
what happens. The variable you change is the “independent” or
“manipulated” variable.
Dependent variable – When you change the independent
variable, you will observe how the dependent variable changes.
We also call the dependent variable the “responding variable,”
since it changes in response to the change you make to the
independent variable.
Experimental Design
Variables 101
Controlled variables – All other variables in an experiment
must stay the same. These are the controlled variables, and
you will want to watch them as close as the dependent
variable. If for some reason one of your controlled variables
changes during an experiment, you will not be able to say that
the results you got were not due to the change in the control
variable or the change in the independent variable.
Finally, all your variables should be measurable.
Let’s look at some examples….
Question
How much water flows
through a faucet at
different openings?
Independent Variable Dependent Variables
(What I change)
(What I observe)
Water faucet opening
(closed, half open, fully
open)
Controlled Variables
(What I keep the
same)
Amount of water flowing
* The Faucet
measured in liters per
* Water pressure, or
minute
how much the water is
"pushing"
"Different water
pressure might also
cause different amounts
of water to flow and
different faucets may
behave differently, so to
insure a fair test I want
to keep the water
pressure and the faucet
the same for each
faucet opening that I
test."
Does heating a cup of
Temperature of the
water allow it to dissolve water measured in
more sugar?
degrees Centigrade
Amount of sugar that
dissolves completely
measured in grams
* Stirring
* Type of sugar
"More stirring might
also increase the
amount of sugar that
dissolves and different
sugars might dissolve in
different amounts, so to
insure a fair test I want
to keep these variables
the same for each cup
of water."
Question
Which AA battery maintains its voltage for the longest period of time in low, medium,
and high current drain devices?
Hypothesis
Hypothesis: As I test for increasingly longer periods of time, the Energizer AA battery
will maintain a higher voltage than other batteries.
Variables
Independent Variable - Time, how long each battery operates
Dependent Variable - Voltage
Experimental Group
Controlled Variables for Each Group
Low current drain
Same portable CD player
Play the same music track
Play at the same volume level
Medium current drain
Identical flashlight
Identical light bulb
High current drain
Same camera flash
All groups
Battery size (AA)
Constant temperature (A battery works better at a warm temperature.)
What Makes for
Good Variables?
If you have
good Variables,
you should be
able to answer
"Yes" to every
question below
Variables Checklist
Yes / No
Is the independent variable measurable?
Yes / No
Can you change the independent variable during the experiment?
Yes / No
Have you identified all relevant dependent variables, and are they all
caused by and dependent on the independent variable?
Yes / No
Are all dependent variable(s) measurable?
Yes / No
Have you identified all relevant controlled variables?
Yes / No
Can all controlled variables be held at a steady value during the
experiment?
Patty Power
Mr. Krabs wants to make Bikini Bottoms a nicer place to live. He has created a new
sauce that he thinks will reduce the production of body gas associated with eating
crabby patties from the Krusty Krab. He recruits 100 customers with a history of gas
problems. He has 50 of them (Group A) eat crabby patties with the new sauce. The
other 50 (Group B) eat crabby patties with sauce that looks just like new sauce but
is really just mixture of mayonnaise and food coloring. Both groups were told that
they were getting the sauce that would reduce gas production. Two hours after
eating the crabby patties, 30 customers in group A reported having fewer gas
problems and 8 customers in group B reported having fewer gas problems.
Which people are in the control group?
What is the independent variable?
What is the dependent variable?
What should Mr. Krabs’ conclusion be?
Why do you think 8 people in group B reported feeling better?
Slimotosis
Sponge Bob notices that his pal Gary is suffering from slimotosis, which occurs
when the shell develops a nasty slime and gives off a horrible odor. His friend
Patrick tells him that rubbing seaweed on the shell is the perfect cure, while Sandy
says that drinking Dr. Kelp will be a better cure. Sponge Bob decides to test this
cure by rubbing Gary with seaweed for 1 week and having him drink Dr. Kelp.
After a week of treatment, the slime is gone and Gary’s shell smells better.
What was the initial observation?
What is the independent variable?
What is the dependent variable?
What should Sponge Bob’s conclusion be?
Patty Power
Which people are in the control group?
Group B
What is the independent variable?
New sauce
What is the dependent variable?
Amount of gas
What should Mr. Krabs’ conclusion be?
The new sauce appears to work as it reduced the amount of gas
produced in 60% of the people tested.
Why do you think 10 people in group B reported feeling better?
They thought they were getting the new sauce as a result thought that
they didn’t have as much gas. (Placebo effect)
Slimotosis
What was the initial observation?
Slimotosis on Gary’s shell
What is the independent variable?
Cures (Seaweed and Dr. Kelp)
What is the dependent variable?
Slime and odor
What should Sponge Bob’s conclusion be?
Although Gary’s symptoms have disappeared, it is not known which cure
was the one that worked. He should redo the experiment and include a
control group as well as two other testing groups for each of the
proposed cures.