Learning the Scientific Method using Experimental Design
Mr. HammBoyceville High School Science
DepartmentBoyceville, WI
Is there a “Scientific Method?”NO!!!
Simply a loosely-bound set of rules/methods to ensure proper experimental testing
Rules/methods are consistent and fixed, but the specifics may change from experiment to experiment
Different experiments require different specifics but the same general format
a. Statement of Problem (2 pts)Not a yes/no question
How does…Must include independent & dependent
variablesHow does the mass of a paper airplane
affect its flight time?Problem is clearly testable and written in a
concise mannerHow does the mass of a ball affect the time
it takes for it to fall from the ground when dropped from a given height?
b. Hypothesis (4 pts)Statement predicts a relationship or trend
If…then statements work bestIf the plane has a higher mass then it will
fly for a longer timeStatement gives a specific direction to the
predictionTake a stand…who cares if you are wrong!Consider the hypothesis above INSTEAD OF:
If the plane’s mass is changed then it will fly for a different amount of time
b. Hypothesis (cntd)Prediction includes both independent & dependent
variablesMass of Plane, measured in grams: Independent
VariableFlight Time, measured in seconds: Dependent
VariableIndependent Variable: The variable that you
change in an experimentDependent Variable: The variable that you measure
in an experiment (the variable that depends on the IV)A rationale is provided for the hypothesis
The flight time for the plane will be longer if its mass is increased because it has additional inertia.
c. Independent Variable (3 pts)Correctly identify the independent variable
(the variable that you change)Operationally identify the independent
variable (how is it changed in your experiment, how is it measured, what are its units, etc.)
State at least three levels of this variableA level is a specific value with unitPlanes with a mass of 2 g, 4 g, 6 gBalls of mass 10 g, 20 g, 30 gRamps of height 5 cm, 10 cm, 15 cm, 20
cm (4 levels)
c. Dependent Variable (3 pts)Correctly identify the dependent variable
The variable that is being measuredThe variable that changes with respect to the
independent variable (depends on the IV)
Operationally identify the dependent variableHow is it measured in the experiment?Units? Tools to measure the DV?How is it used in the experiment?
c. Controlled Variables (4 pts)Controlled variables are other variables
OTHER THAN the independent or dependent variables that are controlled (held constant) in an experimentThe same style of plane is usedThe same type of paper is usedThe paper plane is released from the same
heightThe plane is timed by the same person
every timeThe plane is flown in the same location
every timeThe plane is released by the same person
every timeEtc…
d. Experimental Control (2 pts)Standard of ComparisonThe value of the dependent variable
when the independent variable is minimized or absent, whichever is more applicable
NOT one of your levels of IV if possibleProvide a reason for your selection of the
Experimental Control The experimental control is the flight time
for a paper plane of mass 5 g because that is the lightest paper plane that can be made with these supplies.
e. Materials (3 pts)All materials used are listed (one material per
line)
No extra materials are listed
Materials are listed by their proper name
Material list is separate from the procedure
f. Procedure (6 points)Procedure a numbered list, when each
additional step on a new line1…..2…..3…..Etc..
Procedure well organized, experiment can be replicated completely from procedure
Procedure in a logical sequenceDiagrams usedEvidence of repeated trials in procedure
g. Qualitative Observations (4 pts)Qualitative means quality-based, word-basedDocument observations about:
The results The heavier planes did seem to fly longer The lighter planes flew for shorter durations of time
The procedure and any deviations you needed The hallway was too narrow so the flights with the
heavier planes were moved outside The paper plane instructions in the procedure were
detailed enough to create a strong, durable planeResults not directly related to the DV
The heavier planes tended to bank to the right The lighter planes were harder to fold
Make observations throughout the experiment and report writing exercise.
Quantitative Data (6 pts)All raw data is given with appropriate unitsThe data table is condensed with only most
important data included (statistics in separate data table)
Table is labeled properly, including proper units, column headings, & row headings
Example calculations given where applicable (not all calculations, but at least one of each type)
All data reported with proper number of Significant Figures
h. Quantitative Data (cntd)Mass of Plane (g)
Trial 1 Time (sec)
Trial 2 Time (sec)
Trial 3 Time (sec)
5 g (SOC) 0.82 sec 0.79 sec 0.94 sec
10. g 1.12 sec 1.15 sec 1.21 sec
15 g 1.33 sec 1.52 sec 2.85 sec
20. g 1.56 sec 1.78 sec 0.23 sec
Independent Variable (mass of plane) is included
Dependent Variable (flight time) is included
Standard of Comparison (SOC) is included
i. Graphs (6 pts)Appropriate type of graph used
Usually a line graph or scatterplot with line of best fit
Graph has descriptive and appropriate title
Units included on graph where needed
Appropriate scale used for graph for both axes
Graph labeled properly for axes and series.
i. Graphs (cntd)
4 6 8 10 12 14 16 18 200
0.5
1
1.5
2
2.5
3
f(x) = 0.0352 x + 0.835
Flight Time of Paper Airplanes of Dif-ferent Masses
Mass of Plane (g)
Fli
gh
t T
ime (
sec)
j. Statistics (6 pts)Create a separate data table for statisticsInclude average (mean, median or mode
depending on data) and drawn in line of best fitInclude measure of variation (Range, IQR,
Standard Deviation)Include Equation for Line of Best Fit (Regression
Analysis)Include one other appropriate statistic based on
dataMeasure of Central Tendency – Mean, Median,
ModeRemember your sample calculations
k. Analysis & Interpretation of Data (4 pts)All data are interpreted and discussed
The heavier planes flew for longer timesThe lighter planes flew for shorter timesThe planes were relatively consistent, with
only a couple of outliersUnusual data points (outliers) are commented
onThe long flight time for the 15 g plane was
the result of the timer forgetting to stop the timer
The short time for the 20. g plane was a result of it hitting the wall.
k. Analysis and Interpretation of Data (cntd)Trends in data explained and interpreted
As the data shows, the heavier the plane, the higher the flight time. This is supported by the positive value for the slope of the line of best fit as well as the increase in average flight times as the mass of the plane increased
Enough detail is given to understand the data without even seeing the data table. All statements must be supported by the data.As the data shows…
l. Possible Experimental Errors (3 pts)Possible reasons for the errors are given
The heavy plane hit the wall because it was released at the wrong angle
The light plane didn’t fly well because it was hastily built and wasn’t folded correctly
Important info about data collection givenThe planes were launched in a hallway that wasn’t
wide enough, causing the planes to strike the walls often.
Effect errors had on data discussedSince the planes hit the wall, this resulted in
premature landing and shorter flight times, causing the average to be lower than expected and possibly clouding up the identification of a trend.
m. Conclusion (4 pts)Hypothesis is re-stated
If the plane has more mass as measured in grams, then it will fly for a longer duration, measured in seconds.
Hypothesis is evaluated according to dataAccording to the data, this hypothesis is
supported based on the slope of our line of best fit being positive and the general increase in average flight time as plane mass was increased.
m. Conclusion (cntd)Reasons to accept/reject hypothesis given
Do NOT prove/disprove hypothesisHypothesis is either supported or refuted by
evidence, causing you to either accept or reject your hypothesis.
No middle ground on this…either accept it or reject it.
All statements must be supported by the dataAs the data shows…
n. Applications and Recommendations for Further Use (4 pts)Suggestions for improvement of specific
experimentA wider hallway would result in fewer
experimental errorsA wider range in the levels of the
independent variable would provide stronger evidence
More trials are needed to obtain more evidence
Suggestions for other ways to look at hypothesis givenWas your justification wrong? If so, why?Can you look at the science behind the
hypothesis differently?
n. Applications and Recommendations for Further Use (cntd)Suggestions for further experiments given
Are there other variables to consider?Could you use the same supplies to check
other independent variables and if they also affect the dependent variable?
Does size of plane (surface area) affect flight time?
Does length of plane affect flight time?Practical application(s) of experiment
Longer duration means more lift, more stability…maybe apply to commercial flight?
