A significant part of the SACE Stage 2 Assessment is to design and carry out a practical task to test a
hypothesis. In this task, you are asked to explore some aspect of Projectile Motion and test a
hypothesis about it. This hypothesis may be a result that we have derived as part of our investigation
into the theory of this section of the course, or it may be a hypothesis that you propose yourself,
based upon your understanding of Projectile Motion.
Investigation:
In this activity you are to design a practical which is from Projectile Motion topic. In this task you are
required to:
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Formulate a hypothesis,
Design and conduct an investigation,
Identify variables,
Collect, analyse and interpret data,
Evaluate results,
Form conclusions, and
Communicate your understanding of the relationship between the variables involved in your
design.
Some possible ideas for your Projectile Motion Design Prac you may wish to consider are
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Test some aspect of the Range formula
Test the effect of air resistance on the motion of projectiles
Explore the factors that might affect air resistance
Explore the effect of varying the height of launching a projectile on the range
Explore some aspect of the path of a familiar projectile eg a basketball thrown towards a
goal
Explore the effect of air resistance using a paper plane – what is the shape of the path etc?
Explore the trajectory of a dart as it flies towards a dart board.
Develop a mathematical model of projectile motion affected by air resistance, using a
graphic calculator, and test your model against the motion of a real projectile affected by air
resistance.
You are encouraged to be innovative in how you take readings and measurements in this
exercise. For example you may choose to use video to record the motion and then freeze
frame to determine the horizontal and vertical position at known times. You may choose to
use various projectiles, such as the stream of water coming from a garden hose, a
badminton shuttle, a golf ball rolling down an incline or a screwed up piece of paper thrown
towards a bin a number of metres away.
You can use resources such as the internet, to investigate different techniques to collect data. You
will need to describe safety considerations when working with your chosen apparatus and explain
how they were managed. You are allowed to work in a group but required to submit an individual
practical report which should include:
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Apparatus supplied:
List of materials and equipment needed for the experiment.
Student Report requirements:
This practical require your group to design the experiment and produce a detailed written report.
The report submitted needs to include the following:
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Introduction:
This includes statement of your hypothesis and an explanation why this makes sense, based upon
the theory you have covered. You are encouraged to read widely, for example to explore further the
effect of air resistance, which may form the basis of your hypothesis. This section must make use of
references using the accepted format. See Guidelines for referencing available at
https://www.sace.sa.edu.au/web/physics/stage-2/support-materials/research-advice
DESIGNING AND PERFORMING AN EXPERIMENT TO TEST A HYPOTHESIS (from the subject outline)
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Method:
First section:
In designing an experiment, it is important to identify any variables that might be involved and then
design your experiment to test a relationship between two of these variables, recognising that all
other variables need to be kept constant. It is very important that you make very explicit which is the
independent variable that you manipulate, and which is the dependent variable which is changed by
manipulation in the other. You must also make explicit those variables which must be held constant.
In explaining your method, it is important that you make clear what your expectation is, if the
hypothesis is correct.
Second section:
The second section of the method will explain the practical side of the method – how you will
measure each variable and in particular, what you will do to reduce the effect of random errors. This
section may well contain diagrams of your apparatus, which may include digital photos. An
important element of the method section is the identification of any safety considerations and how
these were managed.
DESCRIBING AND EXPLAINING SAFETY CONSIDERATIONS IN A PRACTICAL INVESTIGATION. (from the
subject outline)
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Results:
This section will be used to display your results. Generally, you should tabulate your results and the
results of any manipulations. Where at all possible, you should graph your results using clearly
labelled axes, including units. You can either graph these by hand on graph paper, or you may make
use of a graph generated by a spreadsheet.
GRAPHING RESULTS (from the subject outline)
DISPLAYING AND INTERPRETING RESULTS (from the subject outline)
RELATING RESULTS TO RELEVANT CONCEPTS (from the subject outline)
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Discussion:
You should compare the results of your experimentation with your expectations and comment on
any errors that seem to be evident in your results. For example, you should comment on any scatter
about an expected straight-line graph and point out that this scatter is evidence of random error in
the experimentation. Likewise, if your graph does not pass through the origin, as expected, or its
slope is significantly different from your expectation you should seek to point it out as evidence of a
systematic error. This discussion of systematic error should include a determination of the % error.
This should be followed by some comment on the source of any error.
IDENTIFYING AND EXPLAINING THE SOURCES OF ERRORS (from the subject outline)
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Suggested improvements
You should give suggestions for improvements that could be made to the experiment. If your
experiment does not provide sufficiently strong support for the hypothesis, you must provide some
plausible reasons why it does not. To do so, you must critically analyse your experiment and provide
some suggestions for improvement. This will include some further comment on the errors discussed
in the discussion section and how your improvement might reduce the effect of these errors.
EVALUATING AN INVESTIGATION OR EXPERIMENT AND SUGGESTING IMPROVEMENTS (from the
subject outline)
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Conclusion:
The most important question to be answered in the conclusion is whether this experiment provided
experimental support for the hypothesis. Remember that no experiment can prove the hypothesis.
Rather, it can only provide support, or disprove.
FORMULATING A CONCLUSION AND MAKING RELEVANT PREDICTIONS (from the subject outline)
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Reference List:
This section contains the publication details of all of the references referred to in the text in the
introduction above. This must be done according to the guideline set out in the Guidelines for
referencing mentioned above.
You should discuss your plan with your teacher before you commence. You may
choose to undertake this experiment in small groups, but it is essential that you
write an individual report.
Centripetal Force Practical Marks
SACE Number ………………………………………
Specific Feature
I1
Mark
Design of a physics investigation.
5
 Discussion of plan with teacher, depends
on the degree of the modification
required by teacher
 Introduction including a testable
hypothesis
 Method including the variables
I3
5
10
Manipulation of apparatus and technological tools to
implement safe and ethical investigation procedures.
 List of apparatus and how they are properly set
up and correctly used
 Description of safety considerations and explain
how they were managed.
I4
3
2
The obtaining, recording, and display of findings of
investigations, using appropriate conventions and
formats.
 Measurement and recording of variables in an
appropriate table
 Graphing data
Total I
AE1
5
5
35
Analysis of data and concepts and their connections, to
formulate conclusions and make relevant predictions.
 A description of any possible errors, including
any random and systematic errors, and their
evidence of existence with regards to precision
and accuracy.
 Explain any step taken to minimise errors
 Compare results obtained from practical with
8
2
4
theory from other sources, eg, text and find a
%error.
 conclusions
AE2
4
Evaluation of procedures, with suggestions for
improvements.
Total AE
A2
2
20
Use of appropriate physics terms, conventions,
formulae, and equations
 Calculations to determine an unknown variable,
eg, calculation of slope to find a constant.
Total A
3
3
KU1
Demonstration of knowledge and understanding of
physics concepts.
3
KU3
Communication of knowledge and understanding of
physics in different formats
4
Total KU
7
TOTAL
65
Student’s Name: ………………………………………………………….. SACE number: ……………………………………….