Download What is an energy chain?

ACTIVITY #6: Where’s the Energy Going?
Using Energy Transfer and Transformation
to Follow Changes in the World Around Us
In this investigation, you will attempt to trace the flow of energy in everyday phenomena.
Whenever any change takes place in the world around us, an exchange of energy is usually part of
that change. Sometimes the energy is transferred between objects; sometimes it also undergoes
transformations into different forms. Keeping track of role that energy plays in these changes often
helps us understand why the changes take place and make predictions about what the changes will
be like. To keep track of the ‘flow’ of energy, we create ‘energy chains’. An energy chain is a
description of how the energy is passed along from one object to another, and what transformations
take place
in the process.
Take
for example
the energy chain of a kicked football. It starts with the food energy inside the
kicker, which is transformed into the kinetic energy of his leg and foot. This kinetic energy is then
transferred to the football. As the ball climbs on its path through the air, part of its kinetic energy is
transformed to gravitational potential energy, and the chain goes on. An example of how energy
chains can help us understand an event … imagine yourself running up to a football, preparing to
kick it, but for some reason, your kicking foot misses the ball. If this has happened to you, you
know that what follows is embarrassing, if not painful. Energy chains can be used to explain why it
is so difficult to maintain your balance and so easy to ‘pull’ a muscle in your leg when you miss a
football. Whenever we observe an event-taking place (or study one that has already taken place),
we can better understand what is happening by asking questions about what happened to the
energy during the event.
•Where did this energy come from?
•How far back can you trace the sources of the energy?
GOALS: In this lab activity, you will …

Identify different forms of energy and how these energy
forms are transferred and undergo transformations in
everyday phenomena.

Construct an energy chain that describes the energy
flow in everyday phenomena.

Use the Particle Model and the concept of energy
transfer to describe how air particles interfere with the motion
of objects.
Activity Overview: A synopsis of this lesson is as follows…
This is an opportunity to use the concepts of energy
transformation (from one energy form to another) and energy
transfer (from one object to another object) to trace the role of
energy flow in any physical process. You will be given examples
and asked to trace the flow of energy using energy chains.
MAKE ENERGY CHAINS
§
Describing energy flow that allowed you to get
from your house to school.
§
Describing the energy flow that enables you to
walk down the hallway at school.
§
Describe the energy flow that allows the
custodian to raise the flag up the flagpole in the
morning.
§
Describe the energy flow that allows a coffee
pot to produce a warm cup of coffee in the morning.
(MOST ENERGY ENDS UP IN THE GRAVE YARD!!—
HEAT ENERGY)

Energy can exist in different forms.
Sometimes the energy of an object is easily detectable, for example, the
energy it has because of its motion (kinetic energy).

Sometimes the energy of an object is more difficult to detect because it is a
stored energy (for example, the gravitational potential energy).

Energy can be transferred from one object to another.
When one object pushes or pulls on another object often (but not always)
energy is transferred from one of the objects to the other. As a result of this
transfer, the motion of one or both of the objects will change.
When kinetic energy is transferred to a large stationary solid this energy
is transferred to the particles that make up the object. The kinetic energy may
take the form of organized vibrations within the solid (a mechanical wave), but
will ultimately become the random vibrational kinetic energy of the particles.
This collective random kinetic energy of the particles is called heat energy.
Energy can be transformed from one form to another. This
process is called the transformation of energy.

When an object is lifted, energy needed to lift it up is transferred to the lifted
object, and transformed into gravitational potential energy.

If an object is thrown upward, its kinetic energy is transformed into potential
energy. The object’s potential energy increases as it travels higher, and the object
slows down as its kinetic energy decreases.

When an object falls or rolls down a ramp, gravitational potential energy is
transformed into kinetic energy. As a result of this transformation, the object’s
kinetic energy increases, and the object’s downward motion speeds up.
In most cases, the kinetic energy of objects in motion eventually becomes the
random kinetic energy of the particles that make up the object. We call this form of
energy heat energy.
By understanding energy transformation and energy transfer, we
can begin to understand that the energy of an object can change
forms and be passed to other objects but cannot be either created
or destroyed.
ENERGY CHAINS
We begin our Energy Chain investigation by reviewing some of the previous material
and seeing just how all of it fits together. We will accomplish this task with the help of
ESPN and skateboarding star Tony Hawk by watching the Sports Figures program
entitled “Boarding School”.
Let’s View the ESPN Sports Figures “Boarding School” Video
REVIEW QUESTIONS ….
•What types (forms) of energy are discussed in the video?
•Compare Tony Hawk’s trips back-and-forth on the half pipe
to the swinging pendulum (soda bottle) from Activity #4.
•In one scene a bowling ball is released from the top and
eventually it comes to a stop at the bottom of the half pipe.
Where did the energy go?
What is an energy chain?
In our everyday life, energy is transferred and transformed continuously. It is
helpful to be able to track the ‘flow’ of energy throughout our everyday life. A map of
what happened to the energy, where did it go, and how did it change, is called an
ENERGY CHAIN.
A good example of an energy chain is an automobile’s use of its input energy. How
much of the energy in the gasoline actually becomes kinetic energy of the car? The
answer is a staggeringly small 12% ! So where does the energy go if not into the kinetic
energy of the car?
How many forms of the ‘wasted’ or ‘discarded’ energy can you identify?

Describe the transfer and transformations that took place that leads to the
formation of these forms of ‘wasted’ energy.

Investigating Further …
What is the earth’s main
source of energy?
The SUN is our primary source of energy for the earth. About
99% of the energy used on the earth stems from the sun. It
provides the energy to power the weather patterns and affects our
home planet’s position in the solar system.
Can you trace the flow of energy backwards from you reading
this page to the sun?
Summary of Activity …
In your journal or notebook, write a concise summary of
this activity.
Be sure to address the following questions and use your
data to support your responses.

How can energy change forms?

How can energy be passes from one object to
another object?

How can an energy chain can be useful in our
everyday life?

Can energy ever be “lost”?