The Scientific Method Example

Steps 1-5

Scientific Method Listing the Steps

Make an Observation Define the Problem Research the Problem State the Hypothesis Experiment to test

Hypothesis Collect and Record Data Analyze Data Draw Conclusions Determine Limitations Report Results If needed, Do more

investigation

Make an ObservationDo you see

something unusual?

Frogs withincorrectnumber oflegs!

As we all know, frogs have four legs.

What’s up

with thesefroggies?

Define the Problem The problem MUST be in the form

of a question The obvious question is: 

› What is causing these deformities?

Research the Problem Gather information related to the

problem› Read, observe, measure, take samples,

etc. How frogs normally develop from eggs The % of frogs with the

deformities Number of other species in

the pond with deformities Previous or new pollutants

in the pond Change in amount of UV

(sunlight) exposure on eggs Etc.

State a Hypothesis A hypothesis is:

› An educated guess, trial answer, possible solution, prediction

› Must be a statement› Must be testable or measurable› Is based on your research

and previous experience

Hypothesizing List possible explanations (alternative

hypotheses) based on your previous experience (what you already know);  and on research you have done  

all of the hypotheses must be testable

Hypothesizing Some possible explanations

(hypotheses) for the frog deformities: Genetic mutation

Chemical Pollution Ultraviolet Radiation Disease (virus or parasite or...?) Loud Rock & Roll Music Aliens from outer space Something else

Genetic mutation-

If this hypothesis is true, then: If we mate deformed frogs the offspring should show similar deformities The deformities should be fairly uniform and predictable The particular deformities should only be found in one species

Chemical Pollution- If this hypothesis is true, then: You should be able to find a likely chemical pollutant in the deformed frog ponds You should be able to isolate the chemical from the pond water You should be able to show that the isolated chemical can cause the exact same deformities in the lab These are minimal predictions;  you may have already thought of the fact that chemical pollution should affect all four limbs equally, or that other organisms from the same ponds should show deformities as well

Ultraviolet Radiation- If this hypothesis is true, then: We should be able to measure unusually high levels of UV radiation at deformed frog sites We should be able to use these same levels to induce the exact same kinds of deformities in the lab Can you think of other predictions based on this hypothesis?

Disease (virus, parasite, etc.)- If this hypothesis is true, then: We should be able to find the disease-causing agent (for example, parasites) at the deformed frog ponds We should be able to find the parasites in the deformed frogs We should be able to use the same parasite to induce the exact same kinds of deformities in the lab

Loud Rock + Roll Music-

Okay, this is testable, but WHY test it??? (get real)

Aliens from outer space- Sorry, this is not allowed because it is not testable using the Scientific Method.  Sheesh!

Something Else-Another possibility that we might think of is predation or cannibalism, which seems to be the best explanation for certain kinds of deformities (frogs with missing limbs).If this hypothesis is true, then, at minimum: We should find frogs and/or other pond critters with evidence that their legs have been damaged or bitten off

Experimenting Testing the hypothesis Pick the hypothesis that makes the

most sense and is easy to test

Then design a controlled experiment

Experimenting Go to the web site for Hartwick College to

see the experiments and how the scientific method was actually used to find out the cause of recently found frog deformities.

http://info.hartwick.edu/biology/def_frogs/Introduction/Update.html (I have a link to this on my website)