Download The Scientific Method - Science Methods Portfolio

Education 421
A.
i.
Must be a question that can be answered by science
ii.
B.
i.
Ethical questions such as “should genetic engineering of
humans be allowed?” are not questions that can be answered by
science.
Historical questions such as “Was the shroud of Turin wrapped
around Jesus?” are not suitable for science either. Historical
research is very different from scientific research.
Should be in the form of “How does _______ affect
_______?”
ii.
iii.
For example, How does temperature affect the rate at which
sugar dissolves?
Or, how does drug X affect the blood pressure of people with
hypertension?
Or, how does the type of laundry detergent affect how clean
the clothes get? This type is often rephrased as “which laundry
detergent works best?” which is fine if you plan to test every
type of detergent on the market.
Purpose of background research
A.
i. To find out what has already been researched
ii. To educate yourself about the topic so you can form
a logical hypothesis
iii. To improve your experimental design for this topic
B.
i.
Sources of background research
The internet – check several we pages to insure
validity of info
ii. Books
iii. People who are knowledgeable in the topic
A.
Must answer your original question
B.
Must be able to be tested with an experiment
C.
D.
A hypothesis is an educated guess (educated
because you have done background research)
It’s ok to be wrong – in fact, in science we
often learn more from an incorrect hypothesis
A.
B.
C.
D.
Limit your independent variable ( the thing you change) to one thing.
i.
Keep everything else constant
ii.
The dependent variable is the result of the experiment (as a scientist I
determine the independent variable, independent starts with I and I
determine it; the dependent variable depends on the independent variable.
Run several trials
i.
3 trials is usually a minimum for experiments but more is better.
The results of your experiment will either support your hypothesis or disprove
it if you design your experiment well. Often kids will say that their experiment
proves their hypothesis, but supports is a much better word since in order to
prove something scientifically, we would have to disprove all other possible
explanations.
The dependent variable should be numerical
i.
Math is the backbone of science because we need it to compare data.
ii.
Often students will need guidance in defining operationally
A.
i.
ii.
iii.
B.
C.
i.
ii.
iii.
i.
ii.
iii.
Results should be put into a table and then a graph.
The results should be displayed in such a way that someone looking at them
for 10 seconds would understand what the experiment showed.
Bar graphs are common since most school science projects have one type of
numerical data. Usually the independent variable is in words and the
dependent variable is numerical.
Line graphs are used when you have numerical data for both the
independent and dependent variables.
Tables should be neat and organized.
Be sure the columns and rows are labelled
Be sure the measurement units are clearly indicated
Students should show all results and then give average trials.
Graphs should be well done!
Be sure students label each axis and have a title on their graph
Since a graph is a visual representation of the data, make them visually
appealing with colour and bold fonts
Graph the averages rather then every data point.
Students look at their table(s) and graph(s)
and form a conclusion based on their
hypothesis.
A.
B.
i.
The conclusion should both answer the
original question and address the hypothesis.
Question: How does the type of laundry detergent affect
how clean cloths get?
ii. Hypothesis: Purex will remove more stains then the other
brands
iii. Conclusion: Tide removed the highest percentage of
mustard stain, which disproves my hypothesis.
A.
B.
C.
This is NOT simply retesting by doing the
experiment over
It is retesting the hypothesis in a different
way.
When experiment is done in a science class I
often had students verify their results with
another lab group