Download Module Objective(s) - Students will…

IES Grant Module Format
Module 8- Kinetic & Potential Energy
Grade Level- 8th
PA State Standard (# & short description)
S8.C.3.1: Describe the effect of multiple forces on the movement, speed, or
direction of an object.
S8.A.3.1: Explain the parts of a simple system, their roles, and their
relationships to the system as a whole.
Module Objective(s) - Students will…Be able to distinguish between kinetic and
potential energy and will understand the conversion of energy from one form to the
other.
Materials/Supplies – Ball, brick, rubber band, smartboard
Picture Prompts - Smart notebook images: brick falling, rubber band stretched
and released, ball being thrown
Essential Question(s): What is energy?
Module #8
1. Do Now: Pre-test (10 minutes)
2. Video Clip: Throwing a ball in slow motion?
3. Vocabulary:
o Energy – the ability to cause change
o Kinetic energy – energy of motion
o Potential energy – energy of position
o Gravitational potential energy - potential energy that is dependent on
the height above earth’s surface.
o Elastic potential energy - potential energy stored in a stretched
rubber band or object that has changed its shape.
o Energy conversions – changes in the form of energy.
o Maximum potential energy - is reached when an object is at its
highest point of “stored” energy.
o Maximum kinetic energy - is reached when an object reaches its
highest velocity.
4. Pre -Activity: (Anticipatory set) : Ask students to describe what happens to
the energy in the ball when it is tossed.
5. Lecture Part 1:
Today we are going to talk about energy. We use the idea of energy to help us
describe how and why things behave the way they do. Please take note, energy can
be defined as the ability to cause change. There are many forms of energy and
each of the forms can cause change. Today we are going to look at two forms of
energy: Kinetic and potential energy.
Please write this down, kinetic energy is energy of motion. An object that moves
has kinetic energy. When you walk, run, swim and jump, you have kinetic energy.
It is important to know that the faster the object moves, the more kinetic
energy it has. So kinetic energy is directly related to the velocity of an object. In
baseball, a fastball has more kinetic energy than a slow curve. You have more
kinetic energy when you run than when you walk.
Please take note, potential energy is the energy of position. Potential energy is
also known as “stored” energy. An object can have stored energy because of these
two factors: its position or its arrangement. Let’s look at a classic example of
potential energy. It you were to pick up a brick and hold it up, that brick would
have potential energy because of its position. When its on the ground, the brick
cannot force anything to move or change. When you pick it up, you apply force and
lift the object. You did work. That work added energy to the brick. Once the
brick is in a higher/new position, we would say that energy was added to the brick
and is now “stored” in the brick as potential energy. Now the brick can do
something it couldn’t do before; it can fall. And in falling, it can exert forces and
do work on other objects. Please write this down, potential energy that is
dependent on the height above earth’s surface is called gravitational potential
energy. Suspension bridges, a wrecking ball before it’s let go, or even a dam
before it is released all have gravitational potential energy. In fact, any object
that is being held above earth’s surface has gravitational potential energy.
Let’s look at another example, think about a rubber band just lying around on a
desk. It cannot force anything to move or change. However, if you pull back on the
rubber band and hold it, it now has stored energy. The energy you used to stretch
the rubber band becomes stored in the rubber band as potential energy because of
its arrangement. Please write this down, potential energy stored in a stretched
rubber band is called elastic potential energy. Elastic potential energy can be
stored in stretched springs as well as stretched rubber bands. In fact, any object
that can be forced into a shape that is different from its natural shape can store
energy.
Now let’s talk about energy conversions. Write this down, changes in forms of
energy are called energy conversions. Kinetic energy is energy of motion.
Potential energy is energy of position. These two forms of energy are continuously
being converted or changed from one form to the other. Think of tossing a ball up
into the air. When you throw the ball up, you give it kinetic energy. As the ball
rises, it slows down. As its velocity decreases, its kinetic energy is reduced. But
during the same process of rising higher and higher from the earth, its potential
energy is increasing. At the top of its path, the ball has slowed down to zero
velocity and zero kinetic energy. All of its kinetic energy from the beginning of its
flight has been converted to potential energy. At this position, it has maximum
potential energy. Write this down, maximum potential energy is reached when an
object is at its highest point of “stored” energy.
Then the ball begins to fall. As it gets closer to the earth’s surface, its potential
energy decreases. But it is speeding up at the same time. Therefore, its kinetic
energy is increasing. When you catch it, it has reached its maximum kinetic
energy. You must know that maximum kinetic energy is reached when an object
reaches its highest velocity.
There are many examples of kinetic and potential energy conversions all around us.
A pendulum swinging in an arc or a diver on a diving board springing up and down are
just a few examples that show this change. Let’s review what we’ve learned.
First energy is the ability to cause change. Kinetic energy is the energy of motion.
Potential energy is the energy of position. It is also called stored energy. There
are two types of potential energy: gravitational potential energy and elastic
potential energy. Energy conversions are changes in the form of energy.
Throwing a ball is an example of a kinetic/potential energy conversion. Maximum
potential energy is reached when an object is at its highest point of “stored”
energy. And maximum kinetic energy is reached when an object reaches its
highest velocity.
This concludes our lecture of kinetic and potential energy.
6. Post-Activity: Kinetic/Potential energy worksheet.
7. Review Notes: Address Note-taking students, “Go to the last page of your
notes and write five lecture points, you may refer to your notes” Address
all other students, “Fill in any gaps in your notes”
8. Post Test: (10 minutes)
9. Homework/Follow-up: Kinetic/Potential energy worksheet.