TEKS 7.8 A
The Force is with You!
TAKS Objective 4 – The student will demonstrate an understanding of motion,
forces, and energy.
Learned Science Concepts
1. Unbalanced forces cause changes in the speed or direction of an
object’s motion.
2. Waves are generated and can travel through different media.
TEKS 7.8 Science concepts
The student knows that complex interactions occur between matter and energy.
The student is expected to:
(A)
Illustrate examples of potential and kinetic energy in everyday life
such as objects at rest, movement of geologic faults, and falling
water.
Overview
The students will examine the relationship between kinetic and potential energy. They
will use experimentation and data collection to see that kinetic energy is a function of
mass and velocity. They will also examine how potential energy is changed due to
condition and position.
Instructional Strategies
Hands-on activities will involve discovery, inquiry, and experimentation. The activities
scaffold learning concepts to strengthen concepts of force and motion. Students will
begin studying linear motion in a nearly frictionless environment. They will apply a force
and measure results. They will next look and unseen forces due to air resistance. Finally
they will use the concept of air resistance to study and explain terminal speed in a
freefall. A second series of exercises will allow students to study two-dimensional motion
where one direction experiences the constant force of gravity. Counterintuitive ideas will
be used to dispel deep-set misconceptions of motion.
Objectives
1. The learner will illustrate real-world examples of potential and kinetic energy.
2. The learner will simulate how pressure affects layers of rock in an earthquake by
applying pressure horizontally to layers of clay to increase potential energy.
3. The learner will determine if potential energy due to height above the earth will
affect kinetic energy of an object.
For Teacher’s Eyes Only
Concepts & Vocabulary
Energy – the ability to cause change
Matter – Anything that has mass and volume
Kinetic energy – the energy of motion; kinetic energy depends on speed and mass
Potential energy – stored energy due to position or condition
Mass – the amount of matter in a substance
Velocity – the speed of an object in a particular direction
Kinetic energy = ½ mass x velocity2
Potential energy = weight x height
Energy is the ability to cause change. It is also often defined as the ability to do work. In
any case energy is the stuff that allows the world to be animated. If it were not for
energy, the world be like a picture with no motion or action of any kind.
All energy is divided into two basic categories: kinetic and potential. The word, kinetic
is derived from the Greek root word “ kinein” which means “to move”. Potential comes
from the Latin word “potere” which translates as “to be powerful”. These are not really
forms of energy as much as states of the different forms of energy.
For example, the forms of energy are heat, light, sound, chemical, atomic, electrical, and
mechanical. Heat can be either kinetic or potential. If a light bulb is not turned on, but it
has the ability to produce light, it has a potential energy in the filament. When electricity
runs through the filament causing it to heat up, the energy then becomes kinetic because
light is actually being produced.
If you hold a rock in the air, it has potential energy to move. It could either be dropped or
thrown. Either way a force acts on the rock to produce motion. The force could be
gravity, which pulls objects down to the earth, or it could be mechanical energy from
your hand moving it.
Potential energy exists either because of an object’s condition or its position. Any matter
can have stored energy. A boulder sitting on the edge of a cliff has potential to fall due to
its position or height above the earth. A wind-up toy has potential energy due to its
condition of being wound up. A piece of wood has stored energy because of its ability to
burn. All energy starts out as potential energy.
The amount of potential energy an object possesses depends on its height above the earth
and its weight. The higher it is, the more potential energy is has. The heavier it is, the
more potential energy it has.
Kinetic energy occurs when potential energy is used or transformed into kinetic energy.
Kinetic energy can also be transferred from one object to another. When a bat is swung
to hit a ball, the kinetic energy of the bat is transferred to the ball.
Kinetic energy is determined by the mass of the object and the velocity at which the
object is moving. If two objects are moving at the same velocity but one has twice the
mass of the other, the object with double the mass has double the kinetic energy.
Student Misconceptions
 Misconception
 Science Concept
Rebuild Concept
 Misconception
 Science Concept
Rebuild Concept
 Misconception
 Science Concept
Rebuild Concept
Student Prior Knowledge
5 E’s
Engage
Demonstration: Come back can
The Come Back Can may be made of an oatmeal box with lid. A lead fishing sinker is
attached to the center of a rubber band with a piece of string. Cut a tiny opening in the
center lid and bottom of the box. Pull one end of the rubber band through the hole in the
bottom of the box and fasten it to the outside with a paperclip. Pull the rubber band
through the inside of the box, then through the hole in the lid and fasten it to the outside
of the lid with a paper clip. Using some books, elevate a board (about 1 meter long).
Place the box on its side at the top of the board and ask what kind of energy the box
possesses. (Potential due to position) Then let the box roll down the board. Ask what
kind of energy the box now has. (Kinetic due to the motion) It should roll, then almost
stop, then begin to roll back the other way. Have the students explain what they think
happened, then explain that the rubber band is winding up inside and giving the box
potential energy due to its condition of being wound up so that it can then have the
kinetic energy to move back in the opposite direction.
Explore
Exploration 1
Activity: Illustrate the Moment
Class Time: 30 minutes
Objective: The learner will illustrate real-world examples of potential and kinetic energy.
Materials:
Blackline Master: Student Worksheet – Illustrate the Moment (Exploration 1)
Drawing paper
Colored pencils or crayons
Student Information Sheet
The students will illustrate examples of kinetic and potential energy. They will divide
their paper into two sections, then draw and label an example of potential energy on one
side and an example of kinetic energy on the other side. The pictures should be displayed
on the walls around the room to encourage students to think of many examples in the
world around them of kinetic and potential energy.
Exploration 2
Activity: Break It Up!
Class Time: 15 minutes
Objective: The learner will simulate how pressure affects layers of rock in an earthquake
by applying pressure horizontally to layers of clay increasing potential energy.
Materials:
Blackline Master: Student Worksheet – Break It Up! (Exploration 2)
Dry sticks
Modeling clay in different colors
Newspaper to protect the work area
Students will simulate how potential energy builds up by the horizontal application of
pressure to layers of clay. They will observe how even a seemingly rigid object (a dry
stick) can bend before it breaks. Then they will form layers of clay from different colors
and observe how applying pressure from the ends (simulating the lateral pressure that
occurs on tectonic plates) will first cause the layers to bend, then break.
Summary Questions – Answer Key
1. Identify the potential energy from the activities above. Potential energy existed in
the stick both as potential heat energy because it will burn and as pressure was
applied to each end of the stick producing unbalanced forces. Potential energy
existed in the clay layers as pressure was applied to each end of the clay
producing unbalanced forces, thus motion (the bending of the clay)
2. Identify the kinetic energy from the activities above. Kinetic energy was produced
when the stick began to bend. Kinetic energy was produced when the clay began
to bend or change shapes as well.
3. How does this simulation illustrate what happens to layers of rock when lateral
pressure is applied? When layers of rock are under pressure either horizontally or
vertically, eventually motion will occur in order to release the pressure. This
energy of motion is of course kinetic energy and results in a fracture in the rock,
which may push together or pull apart, depending on the direction of the
pressure. There are several types of fractures that may occur.
4. Based on your observations in this activity, explain how earthquakes may occur.
Earthquakes are a result of the build-up of pressure either under the earth
pushing up vertically (as when rock becomes superheated and begins to expand),
or laterally when one plate puts pressure on another plate.
Explain
Potential energy exists in all matter and all energy begins as potential energy,
which may become kinetic energy. Potential energy exists either because of an object’s
condition or its position. Any matter can have stored energy. A boulder sitting on the
edge of a cliff has potential to fall due to its position or height above the earth. A windup toy has potential energy due to its condition of being wound up. A piece of wood has
stored energy because of its ability to burn. All energy starts out as potential energy.
The amount of potential energy an object possesses depends on its height above
the earth and its weight. The higher it is, the more potential energy is has. The heavier it
is, the more potential energy it has.
Kinetic energy occurs when potential energy is used or transformed into kinetic
energy. Kinetic energy can also be transferred from one object to another. When a bat is
swung to hit a ball, the kinetic energy of the bat is transferred to the ball.
Kinetic energy is determined by the mass of the object and the velocity at which
the object is moving. If two objects are moving at the same velocity but one has twice
the mass of the other, the object with double the mass has double the kinetic energy.
Elaborate
Elaborate1
Experiment: High Roller
Class Time: 15 minutes
Objective : The learner will determine if potential energy due to height above the earth
will affect kinetic energy of an object.
Materials (per group):
2 chairs
Masking tape
Meter stick
One marble
One eight-foot section of vinyl ceiling molding
Activity Overview : The students will divide into groups of four. They will tape one
end of an eight-foot section of vinyl ceiling molding to the back of one chair and tape the
other end of the molding to the back of another chair. The molding should form a curve
between the two chairs that drops down far enough to just touch the floor. The marble
should be placed at different heights on the ramp (molding) then allowed to free-fall
down the ramp. The height reached on the other side of the ramp will be recorded for
each drop height. The students will then determine if the potential energy due to position
(height) has an affect on the kinetic energy of the marble.
KEY:
Values may vary, but the height the marble reaches on the other side of the ramp (on the
first roll) should be very close to the height it was dropped from.
Summary Questions:
1. The greatest potential energy is at the highest drop position.
2. The greatest kinetic energy is at the bottom of the ramp.
3. Yes. The marble losses potential energy as it nears the floor, but has it all the way
down even as it is falling. It then gains potential energy again as it moves higher
up the other side. So essentially, the marble possesses both kinetic and potential
energy as soon as it is dropped. Only at the floor is the potential energy due to
gravity, at “0”.
Elaborate2
Experiment: Mass in Motion
Class Time: 45 minutes
Objectives:
1. The learner will determine if mass of an object affects kinetic and potential energy of
that object.
2. The learner will determine if potential energy due to height above the earth will affect
kinetic energy of an object.
Materials (per group):
4 meter sticks
4 books of equal size
2 steel balls of equal size but different masses
2 identical cardboard boxes (approximately 10 cm on the sides)
Activity Overview :
Students will determine if mass affect the kinetic energy of an object by using two steel
balls that will hit a box and cause it to move when rolled down a ramp. The kinetic
energy of the ball is transferred to the box and measured by the distance the box moves.
The students will then determine whether of not gravitational potential energy will affect
kinetic energy of a ball by again rolling a ball down a ramp and observing how far a box
is moved.
KEY:
Questions:
1. When did the balls possess potential energy? At the top of the ramp
2. When did the balls possess kinetic energy? When the ball began to move
3. When did the box possess potential energy? When sitting at the bottom of the
ramp.
4. What gave the box kinetic energy? The kinetic energy of the ball was transferred
to the box
5. How would you explain why the box moved in terms of potential and kinetic
energy? The box had potential energy sitting on the floor. The ball gave it kinetic
energy when it hit the box.
6. Compare the distance the two balls moved the box. The ball with greater mass
will move farther.
7. Did both balls possess the same amount of potential energy? Why or why not?
The ball with greater mass had a greater potential energy
8. Did both balls possess the same amount of kinetic energy? Why or why not? The
ball with greater mass had greater kinetic energy due to its mass
9. Were the balls traveling the same speed? How can you tell? Yes. They move the
same distance in the same amount of time.
Questions:
1. Compare the distance the box travels with each change in ramp height. The box
travels a greater distance with each increase in ramp height.
2. Was kinetic energy of the ball affected by ramp height? How do you know? Yes.
The box was moved a greater distance each time the ramp height was increased.
3. Was potential energy of the ball affected by ramp height? How do you know?
Yes. As the height of the ramp increased, the potential energy also increased
because it resulted in greater kinetic energy.
Elaborate 3
Experiment: Kinetic Mouse
Class Time: 45 minutes
Objectives:
Materials (per group):
Activity Overview :
Evaluate
Energy – Potential or Kinetic?
Number your paper from 1-20 and label each of the following as K for possessing kinetic
energy or P for possessing potential energy.
1. a moving skateboard
2. a rock at the edge of a cliff
3. a glass of milk
4. gasoline in a car tank (car is not on)
5. a basketball passing through the hoop
6. a dry cell of a battery
7. an acorn hanging from an oak tree
8. a person climbing a ladder
9. a piece of celery
10. blowing wind
11. a waving hand
12. a wound up music box that is closed
13. a flowerpot sitting on a windowsill
14. a foot kicking a football
15. a lump of coal
16. a running man
17. a burning candle
18. a stretched rubber band
19. a firecracker that has not been lit
20. a moving car
KEY:
1.
2.
3.
4.
5.
6.
7.
8.
K
P
P
P
K
P
P
K and P – the person is moving so he possesses kinetic energy but as he goes
higher on the ladder, he increases his potential energy due to height above the
ground.
9. P
10. K
11. K
12. P
13. P
14. K
15. P
16. K
17. K and P – the candle wax and wick both possess potential energy until they are
gone. The fire is the kinetic energy of both heat and light.
18. P
19. P
20. K
Student Worksheet
Illustrate the Moment
Exploration 1
Student Information:
All forms of energy (heat, light, sound, mechanical,…) exist in two ways:
potential or kinetic. Potential energy is stored energy. It is found in all matter and all
energy begins as potential energy. The second way energy exists is in the form of
motion. Then it is called kinetic energy. Any time you see something move or interact
in any way, kinetic energy is being used.
Kinetic and potential energy are all around you every day. Food contains
potential energy. When we eat it, the energy can be converted into a form we can use to
carry on all daily activities even down to a cellular level. A book sitting at rest on a table
has potential energy because if it falls off the table, motion occurs (kinetic energy).
Anything moving has kinetic energy: a car riding down the road, a roller coaster, a
waterfall, chemical reactions, etc.
Objective: The learner will illustrate real-world examples of potential and kinetic energy.
Materials:
Drawing paper
Colored pencils or crayons
Student Information Sheet
Procedure:
In this activity, you will draw pictures of examples you can find around you of
kinetic and potential energy. Divide your paper into two sides. On one side, draw, color,
and label an example of potential energy. On the other side do the same with an example
of kinetic energy. You may want to check your idea with your teacher or another student
before you begin drawing.
On the back of your paper, put your name, date, and period # and tell how your
drawings illustrate kinetic and potential energy.
Student Worksheet
Break It Up!
Exploration 2
Forces are constantly pushing and pulling on the earth’s crust. The earth’s crust, which
continues from dry land to the land under the sea, is thought to be composed of several
really large “plates” of earth. These plates are constantly moving even though those
motions are not obvious to us. There are also huge cracks within the plates called fault
lines. As the cruse floats on the layer beneath it, called the mantle, pressure is created
horizontally. If pressure becomes great enough between plates or at fault lines, the earth
will bend and may eventually crack causing an earthquake. In this activity, you will be
using dry sticks and clay to simulate what happens to layers of rock when pressure is
applied laterally. Then you will make inferences about what causes an earthquake.
Objective: The learner will explain the results of applying a pressure horizontally to
layers of clay increases potential energy which when pressure is sufficient becomes the
kinetic energy of motion in order to simulate how pressure (potential energy) affects
layers of rock in an earthquake.
Problem 1: Will a dry stick bend before it breaks?
Problem 2: What affect will applying horizontal pressure to each end of several layers
of clay stacked on top of each other have on the layers?
Materials:
Dry sticks
Modeling clay in different colors
Newspaper to protect the work area
Procedure:
Part 1
Take the dry stick and hold it at each end. Find out if a dry stick will bend before it
breaks. Record your observations here.
Part 2
Using the clay, flatten out several layers of different colors and place them on top of each
other. Placing your hands at each end, push the layers together horizontally. Record you
observations here.
Summary Questions
1. Identify the potential energy from the activities above.
2. Identify the kinetic energy from the activities above.
3. How does this simulation illustrate what happens to layers of rock when lateral
pressure is applied?
4. Based on your observations in this activity, explain how earthquakes may occur.
High Roller
Elaborate 1
Objective: The learner will determine if potential energy due to height above the earth
will affect kinetic energy of an object.
Problem: How does potential energy due to position (height above the earth) affect
kinetic energy of a marble to roll back up a curved ramp?
Materials (per group):
2 chairs
Masking tape
Meter stick
One marble
One eight-foot section of vinyl ceiling molding
Meter
stick
Procedure:
Part 1
1. Place two chairs, back sides facing each other, about 3 meters apart.
2. Using the masking tape, tape one end of the vinyl molding to the top back of one
chair and the other end to the top back of the other chair.
3. Adjust the distance between the two chairs so that the molding ramp just touches
the floor. Then tape the sides of the ramp to the floor.
4. Place the marble on the floor in the center of the ramp. What is the potential
energy of the marble due to gravity?
5. Now hold the marble against side of the ramp 10 cm above the floor and release it
carefully. How far does the marble travel up the other side? (Measure the
distance from the floor the marble travels up the other side of the ramp.) Enter
this information into your data table.
6. Repeat step 5 at 20 cm, 30 cm, 40 cm, and 50 cm. Each time record your data on
the data table.
Data Table – High Roller
Height of marble
upon release
Height marble travels up
other side of ramp
Part 2
Using the data you collected, graph the information. What is your dependent variable?
your independent variable?
Summary Questions
Part 3
1. When does the marble have the greatest amount of potential energy?
2. When does the marble have the greatest amount of kinetic energy?
3. Does the marble ever possess both kinetic and potential energy? If so when?
4. Based on the graph of your data, how would you describe the relationship
between kinetic and potential energy of the marble?
Mass in Motion
Elaborate 2
Problem: Does mass affect the kinetic energy of an object?
Materials:
4 meter sticks
4 books of equal size
2 steel balls of equal size but different masses
2 identical cardboard boxes (approximately 10 cm on the sides)
Part 1
Procedure:
1. Cut one end and one side out of each box.
Cut out one end.
Cut out one side
(bottom is open).
2. Create a ramp by taping two meter sticks side by side so that there is a groove in
the middle to support the steel ball. Elevate the meter sticks by using three books.
(You will have two set-ups: one with one steel ball and the other with the steel
ball of a different mass.)
3. Place a box at the lower end of each ramp to catch the ball when it
rolls down the ramp.
4. To release the marbles, place a ruler across the top of the meter
sticks just below the marbles, then quickly remove the ruler.
5. Measure the distance each box travels and enter it into your
data table.
6. Return the boxes to their original position and repeat two more times.
7. Average your results.
Distance box traveled
Ball with smaller
mass
Ball with larger
mass
Trial 1
Trial 2
Trial 3
Average distance
the box was
moved
Questions:
10. When did the balls possess potential energy?
11. When did the balls possess kinetic energy?
12. When did the box possess potential energy?
13. What gave the box kinetic energy?
14. How would you explain why the box moved in terms of potential and kinetic
energy?
15. Compare the distance the two balls moved the box.
16. Did both balls possess the same amount of potential energy? Why or why not?
17. Did both balls possess the same amount of kinetic energy? Why or why not?
18. Were the balls traveling the same speed? How can you tell?
Conclusions:
Part 2
Using the same set up as in part 1, choose one ball to test. This time change only the
height of the ramp starting first with two, then three, then four books.
Distance box travels when struck by marble
Two books
Three books
Four books
Trial 1
Trial 2
Trial 3
Average distance
box moves
Questions:
1. Compare the distance the box travels with each change in ramp height.
2. Was kinetic energy of the ball affected by ramp height? How do you know?
3. Was potential energy of the ball affected by ramp height? How do you know?
Conclusions:
Problem: To construct a mouse toy that will move across the floor based on the
amount of potential energy stored in a twisted rubber band.
Materials:
Craft foam (9” x 12”)
String (1 meter)
Duck tape the same color as the foam
Small curtain ring (2 cm diameter)
Pattern
Large wooden spool
Scissors
Drill with 5/64” drill bit
Glue
Rubber band slightly longer than length of spool
Craft eyes
Wire coat hanger
Wire cutter
18 gauge floral wire stick
Procedure:
1. Using the pattern, cut out the pieces of the mouse from craft foam.
2. Tape the top sections of the mouse together with small strips of duck tape. Leave
a 2 cm opening for the string to come through.
Craft foam
Duck tape
3. Connect the tail with glue or staple it on.
4. Glue the ears and eyes on.
5. Cut a section of coat hanger wire and bend it according to the shape of the pattern.
1.
Drill a small hole through the center of the wooden spool.
2. Insert the rubber band through the large center hole of the spool.
3. Insert a small wire into the drill hole making sure it goes through the center of the
rubber band.
4. Bend the ends of the wire flush with the spool and tape them down securely with
the duck tape.
5. Hook the ends of the coat hanger wire to each end of the rubber band.
6. Tie a string around the spool and wrap it around and around until you only have
enough string left to exit the mouse’s body at the top and tie the end to the curtain
ring.
7. Connect the wire and spool apparatus to the mouse body with duck tape. (Before
attaching, notice which direction the spool will move when you pull the string and
twist the rubber band inside, or your mouse will move backwards)
8. Pull the curtain ring through the hole in the top of the mouse body.
9. Now set the mouse on the floor, pull the string and let her go.
Questions:
1. What is potential energy?
2. What is producing potential energy in the mouse?
3. Can the amount of potential energy be increased? Decreased? If so, how?
4. What simple machine is represented in the mouse?
5. Will changing the size of the spool, change the distance the mouse travels? Is so,
in what way?
6. What is kinetic energy?
7. How is kinetic energy displayed in the model of the mouse?
Energy – Potential or Kinetic?
Number your paper from 1-20 and label each of the following as K for possessing kinetic
energy or P for possessing potential energy.
1. a moving skateboard
2. a rock at the edge of a cliff
3. a glass of milk
4. gasoline in a car tank (car is not on)
5. a basketball passing through the hoop
6. a dry cell of a battery
7. an acorn hanging from an oak tree
8. a person climbing a ladder
9. a piece of celery
10. blowing wind
11. a waving hand
12. a wound up music box that is closed
13. a flowerpot sitting on a windowsill
14. a foot kicking a football
15. a lump of coal
16. a running man
17. a burning candle
18. a stretched rubber band
19. a firecracker that has not been lit
20. a moving car