Kinetic and Potential Energy
High School Physical Science
Annotated with Oklahoma Priority Academic Student Skills
Teacher’s Guide
Assumptions
This lesson assumes that students are already familiar with the concept of work. There is a graphic on slide 17
that can be used to review work; however, no attempt is made to exhaustively discuss work in this lesson.
Materials
KineticAndPotentialEnergy.pptx
WorkIsRelatedToEnergy.pdf
HelmetDesignSpreadsheet.xlsx
HelmetDesignActivity.pdf
Digital scale
Playground balls, basketballs, or similar ( 1 per group )
Rubber bands ( 6 – 12 per group )
Variety of plush, cushion-type materials ( enough for each group to try a few combinations )
Meter sticks ( two per group )
PowerPoint
This lesson is designed to accompany the PowerPoint presentation Kinetic&PotentialEnergy.pptx
Slide 1:
Title
Slide 2:
Students should answer questions on slide and discuss among themselves and with the teacher what
energy is, where it comes from and in what forms it exists. Teacher should ask probing questions until
satisfied that his/her class understands the essence of energy.
Slide 3-14:
Ask students to identify where, how, and in what form energy is present in these images.
HS-Physical Science-Process Standard: 2.1, 2.2, 6.2, 6.3, 6.4
HS-Physical Science-Standard: 4.1
Slide 3:
Students should discuss and be lead to the conclusion that electric potential energy is stored in the
batteries shown in this hybrid car chassis.
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Teacher’s Guide
Slide 4:
Students should discuss the energy involved in propelling a hybrid car, namely how the electric potential
energy from the previous slide is being converted to kinetic energy.
Slide 5:
Students should discuss the energy being imparted into the elastic bands of the sling shot by the boy.
Slide 6:
Students should discuss how the potential energy stored in the elastic bands was released, converted into
kinetic energy and propelled a projectile.
Slide 7:
Students should discuss that the plane is moving and therefore has kinetic energy.
Slide 8:
Students should discuss that contained in the tank of this truck is jet fuel which is chemical energy that can
be converted into kinetic energy by a jet plane.
Slide 9:
Follow the link to http://www.hint.fm/wind/ to view a live wind map of the United States. Students
should discuss that wind, itself, has kinetic energy and also possesses the potential to do work.
Slide 10:
Students should discuss how a wind farm is used to harness the potential energy in wind to produce
electricity.
Slide 11:
Students should discuss that the light bulb has gravitational potential energy and that the spring on the
mousetrap is storing elastic potential energy.
Slide 12:
Students should notice in the animation that the light bulb is falling and therefore has kinetic energy. The
kinetic energy of the falling light bulb is used to release the stored elastic energy of the spring.
Slide 13:
Students should discuss the chemical energy stored in food.
Slide 14:
Students should discuss how football players convert the chemical energy in food to the kinetic energy of
their moving bodies.
Slide 15:
This slide should be used to introduce students to how the concepts of energy that they have been
discussing apply to football safety. The animation on this slide depicts a football helmet being drop tested.
Slide 16:
Activity 1: Work is Related to Energy
In this activity, students should each choose three ordinary classroom objects of varying masses. Students
should weigh the objects that they choose and record their masses in the table provided in the ‘Work is
Related to Energy’ worksheet. After recording the masses of their objects, students should lift their
objects a measured distance and make note of how difficult it was to lift the objects of varying masses
⁄ ) as the acceleration
while comparing each to the others. Using the acceleration of gravity (
value for all fields, have the students calculate the work involved in lifting their objects to any distance
they choose.
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Teacher’s Guide
HS-Physical Science-Process Standard: 1.1, 1.2, 1.3
HS-Physical Science-Standard: 3.1
Slide 17:
This slide can be used as a review of work and to introduce the joule.
Slide 18:
Using the provided equation, and the heights they chose to lift their objects, students should record in the
provided table how fast their objects will be moving when they hit the ground if dropped from the heights
they chose.
Slide 19:
Students should use the provided equation to calculate the kinetic energy their objects will possess at the
moment they hit the ground and record that value in the provided table. Comparing the kinetic energy of
their falling object when it hits the ground to the amount of work involved in lifting the object to their
chosen height, students should realize that the amount of work imparted on their object is equivalent to
the amount of energy released at the end of its fall. –all of the objects potential energy is converted to
kinetic energy when released.
Slide 20:
Pause here to discuss with students how important this concept of energy conversion is. Ask students if
they can think of other instances where one form of energy is converted to another form. Guide students
toward instances that involve the cyclic conversion of energy.
Slide 21:
The diagram on this slide is to be used to illustrate to students that at any point along a pendulum’s path
its kinetic energy added to its potential energy is always the same ammount. That is, at the highest point
along the pendulum’s path it is full of potential energy and has no kinetic energy. After falling a bit, it has
slightly less potential energy, but also has an amount of kinetic energy equivalent to its difference in
potential energy. At the pendulum’s lowest point it is full of kinetic energy and has no potential.
HS-Physical Science-Process Standard: 6.3
HS-Physical Science-Standard: 3.1, 4.1
Slide 22:
The animation on this slide illustrates the flow of potential energy to kinetic energy and kinetic energy to
potential energy. Note the fluctuating bar graphs in the top, right-hand corner.
End Activity 1
Slide 23:
Activity 2: Helmet Design
This activity requires students to apply their knowledge of kinetic energy and apply it to helmet design.
See the Helmet Design handouts for step-by-step directions on how to perform this activity. This activity
requires students to design a helmet that will absorb as much kinetic energy as possible using a
playground ball as an analog for a human head, a variety of plush material, and linked rubber bands as a
chin strap that will absorb as much kinetic energy resulting from a fall as possible. Ideally, the instructor
3
Teacher’s Guide
will not limit how much material students use to design an effective helmet. Of course, the less material
used by each group the more realistic their design will be; however, as long as each group designs an
effective helmet that demonstrates the students’ knowledge of kinetic energy, they have achieved the
intended goal of this lesson. The helmet design process is intended to be iterative. That is, after the
students test their first helmet design they should be encouraged to consider changes that will improve
the performance of their design. Students should only be limited by time or materials.
The Student Worksheet document is intended for students to record the results of their tests. It
resembles the HelmetDesignSpreadsheet.xls and includes instructions and equations to use when
populating the table with data. Assign each group a number. This will be used in a spreadsheet to display
their data.
A spreadsheet, HelmetDesignSpreadsheet.xls, has been provided for the instructor to input studentgenerated data that will perform calculations for which to check student calculations with and to display
the performance of each group in the form of a bar graph. Only the fields highlighted in red require data
input. All others will self-populate. The data highlighted in blue is graphed on another page. In this
document there are two tabs. The ‘Input’ tab is intended for instructors to input data reported by students
as they test their designs. At the conclusion of the lesson the instructor should show the students’ the bar
graph included on the ‘Output’ tab to show the class how their design performed relative to their
classmates’ designs.
In the SpreadsheetExplaination.pdf is an explanation for the instructor to use if they have any questions
concerning how the spreadsheet performs its calculations. Note that the Adjusted Percent Energy
Absorbed by Helmet field accounts for the difference in mass between the ‘With Helmet’ and ‘Without
Helmet’ trials.
HS-Physical Science-Process Standard: 7.1, 7.2, 7.3, 7.4, 7.5, 7.6
Slides 24 – 28: Example photos
Slide 24:
Place meter sticks end-to-end against wall and measure from bottom of ball
Slide 25:
Link rubber bands together to function as chin strap. Each group should use the same number and type of
rubber bands as different tensions could vary results from group to group
Slide 26:
Use a rubber band to link the loose ends of ‘chin straps’ together
Slide 27:
Helmet design examples
Slide 28:
Measure from bottom of helmet
4
Spreadsheet
Without Helmet
Mass { kg } :
measured mass of ball without helmet
Initial Height { m } :
Explaination
initial height measured from bottom of ball
Kinetic Energy at Ground { J } = 𝑚𝑎𝑠𝑠 × 9.81 𝑚 𝑠 2 × 𝑖𝑛𝑖𝑡𝑖𝑎𝑙 ℎ𝑒𝑖𝑔ℎ𝑡
Return Height { m } : maximum height of ball after collision measured from bottom of ball
Return Kinetic Energy { J } = 𝑚𝑎𝑠𝑠 × 9.81 𝑚 𝑠 2 × 𝑟𝑒𝑡𝑢𝑟𝑛 ℎ𝑒𝑖𝑔ℎ𝑡
Percent of Initial Energy Absorbed During Impact { % } =
Percent Remaining of Initial Energy { % } = 1 −
𝑘𝑖𝑛𝑒 𝑡𝑖𝑐 𝑒𝑛𝑒𝑟𝑔𝑦 𝑎𝑡 𝑔𝑟𝑜𝑢𝑛𝑑 − 𝑟𝑒𝑡𝑢𝑟𝑛 𝑘𝑖𝑛𝑒𝑡𝑖𝑐 𝑒𝑛𝑒𝑟𝑔𝑦
𝑘𝑖𝑛𝑒𝑡𝑖𝑐 𝑒𝑛𝑒𝑟𝑔𝑦 𝑎𝑡 𝑔𝑟𝑜𝑢𝑛𝑑
𝑘𝑖𝑛𝑒 𝑡𝑖𝑐 𝑒𝑛𝑒𝑟𝑔𝑦 𝑎𝑡 𝑔𝑟𝑜𝑢𝑛𝑑 − 𝑟𝑒𝑡𝑢𝑟𝑛 𝑘𝑖𝑛𝑒𝑡𝑖𝑐 𝑒𝑛𝑒𝑟𝑔𝑦
𝑘𝑖𝑛𝑒𝑡𝑖𝑐 𝑒𝑛𝑒𝑟𝑔𝑦 𝑎𝑡 𝑔𝑟𝑜𝑢𝑛𝑑
With Helmet
Mass { kg } :
measured mass of ball-helmet system
Initial Height { m } :
initial height measured from bottom of ball
Initial Kinetic Energy { J } = 𝑚𝑎𝑠𝑠 × 9.81 𝑚 𝑠 2 × 𝑖𝑛𝑖𝑡𝑖𝑎𝑙 ℎ𝑒𝑖𝑔ℎ𝑡
Return Height { m } : maximum height of ball after collision measured from bottom of ball
Return Kinetic Energy { J } = 𝑚𝑎𝑠𝑠 × 9.81 𝑚 𝑠 2 × 𝑟𝑒𝑡𝑢𝑟𝑛 ℎ𝑒𝑖𝑔ℎ𝑡
Percent Absorbed by Helmet { % } =
𝑖𝑛𝑖𝑡𝑖𝑎𝑙 𝑘𝑖𝑛𝑒𝑡𝑖𝑐 𝑒𝑛𝑒𝑟𝑔𝑦 − 𝑟𝑒𝑡𝑢𝑟𝑛 𝑘𝑖𝑛𝑒𝑡𝑖𝑐 𝑒𝑛𝑒𝑟𝑔𝑦
𝑖𝑛𝑖𝑡𝑖𝑎𝑙 𝑘𝑖𝑛𝑒𝑡𝑖𝑐 𝑒𝑛𝑒𝑟𝑔𝑦
Adjusted Percent Absorbed by Helmet (accounts for mass difference added by helmet) { % }
=
𝑝𝑒𝑟𝑐𝑒𝑛𝑡 𝑟𝑒𝑚𝑎𝑖𝑛𝑖𝑛𝑔 𝑜𝑓 𝑖𝑛𝑖𝑡𝑖𝑎𝑙 𝑒𝑛𝑒𝑟𝑔𝑦 − 𝑝𝑒𝑟𝑐𝑒𝑛𝑡 𝑎𝑏𝑠𝑜 𝑟𝑏𝑒𝑑 𝑏𝑦 ℎ𝑒𝑙𝑚𝑒𝑡
𝑝𝑒𝑟𝑐𝑒𝑛𝑡 𝑟𝑒𝑚𝑎𝑖𝑛𝑖𝑛𝑔 𝑜𝑓 𝑖𝑛𝑖𝑡𝑖𝑎𝑙 𝑒𝑛𝑒𝑟𝑔𝑦