Internal assessment resource Yr10 Investigation & Physics 1.1 for Achievement Standard 90935
Pakuranga College
Science Faculty
Student Name:
Class Teacher:
Date:
Achievement Standard Science 90935: Carry out a practical physics investigation that leads to a linear
mathematical relationship, with direction
Resource Reference: Physics 1.1 AS91135 v3
Resource Title: Bouncing Balls
Credits: 4
Achievement Criteria
Curriculum
Level
<4
Investigatin
g in
Science
4
4+
5-
5
5+
6Achievement
6
Achievement
with Merit
6+
Achievement
with Excellence
Investigate an
astronomical
or Earth
science event.
Investigate,
in-depth, an
astronomical or
Earth science
event.
Investigate,
comprehensively
, an
astronomical or
Earth
science
event.
Student instructions
Introduction
This assessment activity requires you to investigate and determine the mathematical relationship
between the height at which a ball is dropped from and the height of its first bounce.
Bouncing balls
When a ball is dropped, it appears to bounce higher if dropped from a greater height than if dropped from a
lower height. .
Your task is to investigate how the height of drop affects the height
of the bounce of a ball. You will need to determine the mathematical
relationship between the height at which a ball is dropped from and the
height of its first bounce. You will carry out this investigation in small
groups for the planning, and collection of results. The analysis of data,
conclusion and discussion will be written individually.
You will be assessed on how comprehensive your investigation is and
how well you validate your conclusion.
Task – can be completed digitally or written
General method
Use the diagram on the right to help plan your investigation.
Internal assessment resource Yr10 Investigation & Physics 1.1 for Achievement Standard 90935
Equipment
A ball and a 1m ruler.
Plan the investigation
o Use the equipment your teacher provides to trial some possible ways to undertake the investigation.
You may use a camera to record you data.
o Use the planning sheet to think about and record the key variables in this experiment and plan
your investigation.
o You can use the information from your planning sheet to write up your method if you want to.
Collect data
o Using your group method as a starting point, collect data.
o Record your group’s raw data on a white board without processing.
o Record modifications your group make to your method.
o Record any difficulties your group encounters while gathering the data and how you improve your
method to minimise them.
NOTE: Each student makes a copy (digital or written) of the raw data from the white board
Analyse the data (individual activity)
o Copy your raw data into a table (with clear titles and units) on your data sheet and process it.
o Use your group data to plot a line graph. Ensure that your line graph has a title and the axes have
labels and units.
o Draw a line of best fit on the graph.
o Calculate the gradient of the line. Show your working on the data analysis sheet.
Write a conclusion and discussion (individual activity)
o Write a conclusion that relates to the aim/purpose of the investigation, including any
mathematical relationship determined.
o Write a discussion in which you validate your conclusion. It should include:
▪ an explanation of your choice of values for the independent variable
▪ statements that explain the techniques you used to ensure accuracy
▪ justification for other accuracy improving techniques
▪ for each controlled variable, statements about why they were necessary
▪ a description of any difficulties you had when making measurements and what you did to try
to overcome these difficulties in order to improve the data you gathered
▪ reasons for the exclusion of any data from your processing (anomalous results)
▪ a link between your findings and relevant principles of physics
Resource 1: Planning Sheet
1. Purpose of investigation (This may be an aim, testable question, prediction or hypothesis)
The aim of our investigation is to see how the height of drop affects the height of the bounce of the ball
2. Which variable will be changed? (This is the independent variable).
We will change the height that we drop the ball
How will the independent variable be changed?
we will change the height where we drop the ball by holding the base of the ball at the height we are
going to drop it from
List the range of values you will use for this variable.
20, 40, 60, 80, 100 cm
Internal assessment resource Yr10 Investigation & Physics 1.1 for Achievement Standard 90935
3. Which variable will have to be measured of observed in order to get some data or information from the
investigation? (This is the dependent variable).
we will measure the bounce height of the ball
4. How will the dependent variable be measured?
we will record the ball bouncing up against and slow down the footage to determine how far up along the
meter ruler the ball bounces.
5. Other variables that need to be controlled to make your results more accurate (minimum of 3
required).
Other variables
Same tennis ball
Describe how this variable will be controlled or measured?
we will use tennis ball 1 so that we get the same elasticity in every trial
Same surface we drop on to
we will drop the ball on the same surface (classroom bench)
Ball bouncing straight
we will make sure the ball bounces perpendicular to the bench by
clearing the landing space of any obstacles and dropping the ball without
any spin
same point of the ball we
are measuring
we will take all recordings from the lowest point of the ball so that we are
always measuring from the same point
6. How will you ensure that your results are reliable?
we will repeat each test 3 times then take averages in order to remove any anomalies
we will record the ball’s bounce at eye level to remove any parallax error
7. Notes/observations from your trials AND state if you made any changes made to your method.
Resource 2: Planning Sheet
Method: Use the information you provided on the planning sheet to write a detailed step-by-step method.
1.
2.
3.
4.
5.
6.
7.
8.
set up meter ruler
complete first test by suspending the ball with the lowest point of the ball at 20cm
set up to record drop with camera from eye level to remove any paralax error
start recording
drop the ball ensuring the ball drops in a straight line without spinning.
review the recording to find the highest point in the bounce and record that value
repeat steps 2-6 two more times then take an average
repeat steps 2-7 with the different independent variables (40, 60, 80, and 100cm)
Changes made to method.
Internal assessment resource Yr10 Investigation & Physics 1.1 for Achievement Standard 90935
Resource 3: Data Sheet
Data Table: Present your results in an appropriate table and process them and insert below.
Height ball bounces to (cm)
height the ball is
dropped from(cm) trial 1
trial 2
trial 3
average
average 2dp
20
12.4
12.9
12.8
12.7
12.7
40
23.8
24.8
24.5
24.36666667
24.36
60
36.5
34.4
35
35.3
35.3
80
46.6
46.7
45.3
46.2
46.2
100
56.6
54.6
56.9
56.03333333
56.03
Graph of results: Present your results in an appropriate graph and insert below.
Resource 4: Analysis Sheet - USE AS MUCH SPACE AS YOU NEED
Interpretation of Data: Comment on what your data means. This could include a comment on any pattern
or trend shown in your data.
Equation
y=0.543x+2.37
Height the ball bounces = 0.543*height the ball is dropped from + 2.37
where as the height the ball is dropped from increases the height the ball bounces to also increases.
gradient=0.543
Internal assessment resource Yr10 Investigation & Physics 1.1 for Achievement Standard 90935
Conclusion: Link the conclusion to the purpose (aim) of your investigation and state the equation of the
mathematical relationship
From our experiment, we can conclude that as the height the ball is dropped from increases the height
the ball bounces to also increases. This can be seen in the equation y=0.543x+2.37 where y is Height the
ball bounces and x is height the ball is dropped from. The positive gradient (0.543) shows us that this is a
positive linear relationship where as the height the ball is dropped from increases the height the ball
bounces to also increases.
Resource 5: Evaluation Sheet
This could include:
Discussion: a link between investigation findings and applicable physics ideas,
Evaluation: a justification for the accuracy-improving techniques used, a reason that there is a limit to either
end of the value chosen for the independent variable, a justification why a variable needs to be controlled, a
description of any difficulties encountered when making measurements and how these difficulties were
overcome, a description of any unexpected outcomes of the processing of the results and a suggestion of
how these outcomes could have been caused and/or the effect they had on the validity of the conclusion.
In our experiment we used an I.V. range of 20, 40, 60, 80, and 100cm drop heights. We chose to have an
interval of 20cm between each value as that gave enough of a margin between values for us to
effectively measure bounce height and draw out a linear relationship without variability in the results
getting in the way. We chose to use 20cm as our minimum value as this value works with our intervals of
20cm and still provides the ball with enough potential energy to effectively bounce up to a point that we
can effectively measure. If we were to have used a lower minimum we could expect the ball not to
bounce high enough for us to effectively measure. We chose a maximum of 100cm as that is the 5th
value from 20cm (the minimum) that follows of intervals of 20cm. Having an I.V range with 5values gives
us enough points to find a valid linear relationship between the drop height of the ball and its bounce
height.
The reason that as the height we drop the ball from increases the height the ball bounces back up also
increases is a result of the gravitational potential energy that goes into the ball before we drop the ball
increasing as the height we suspend the ball above the bench increases. An example of this is when we
compare the gravitational potential energy of the ball when we suspend it from 20cm (P.E=0.0585(mass
of the tennis ball (kg))x 9.8(gravity) x 0.02(height ball is suspended (m))=0.011466J) to the Potential
energy of the same ball when we suspend it from 100cm (PE=0.0585(mass of the tennis ball (kg))x
9.8(gravity) x 0.1(height ball is suspended (m))=0.05733J). We can see that when we just change the
drop height of the ball there is a visible change in the amount of potential energy in the ball. When we
drop that ball we change that Potential Energy into kinetic energy then when the ball hits the ground the
kinetic energy works to deform the ball. This deforming of the ball causes compressional energy because
of the air inside the ball which works to reconstruct the ball, sending the ball back up, transferring that
compressional energy back into kinetic energy. Because energy can only be transferred/ converted the
kinetic energy in the ball bouncing back up is directly correlated to how much potential energy the ball
has before it is dropped so that when the height the ball is dropped from increases, the potential energy it
has before its dropped increases resulting in a greater amount of kinetic energy in the ball when it is
bouncing back up resulting in a higher apex in the bounce. This is why there is a positive linear
relationship between the drop height of the ball and the height it bounces back up to.
Internal assessment resource Yr10 Investigation & Physics 1.1 for Achievement Standard 90935
Controls
In order to make our investigation valid, we use the same tennis ball for every test. If we were to have
changed the ball we used during the testing we would have made our investigation invalid because how
a tennis ball bounces depends on the air inside the ball to reform the ball after it is deformed from the
drop. Different amounts of air would affect how much compressional energy is used to bounce the ball
back up affecting the bounce height of the ball. Using a different ball would mean that there is a different
inflation in the ball used.
Another thing we did to make our investigation valid was use the same surface that the ball was dropped
on to. Because the bounce of the tennis ball requires the kinetic energy from the falling ball to be used to
deform the ball. Different surfaces would limit how much energy goes into deforming the ball by
absorbing some of the energy.
We measured the bounce from the same point along the ball (the base of the ball) for validity. If we were
to have changed that point we would have had different measurement for the same bounce height.
Note: Not all criteria listed above are required for the awarding of a particular level – but provide a guide of
the evidence we are looking for. How well you answer within each level will be indicated with - or +.
Levels 4 & 5 do not meet NCEA Level 1.