Lesson 2

It also requires apples or small objects, plastic cups and hole punchers.

This lesson explores the question:
“What makes ALL the various types of energy, energy?”
It uses the ideas of length and force to explain.
(The NGSS mandates that forces (pushes and pulls) be taught prior to this class.)
This lesson will serve either as a review or an introduction to forces.

1 What did you do last time? 2 chemical nuclear potential kinetic energy sound PRINT the word next
to the image on the next slide.
EN-lesson P1 L2 ene kin pot sou nuc che
What do all these types
of energy have in common?
What IS energy?
5 To understand energy, you must first understand distance and force. Defining Energy! How tall are you? Measure the length of your finger. Begin with distance. Measure
your height.
Find a ruler or
tape measure.
6 Measure the width of a room. A length is a distance.
A height is a distance.
A width is a distance.

What units have you used
to measure distances?

How long is an inch,
a foot, a yard, or a mile?

Think metric! How long is a centimeter, a meter, or a kilometer?
All of these units are used to measure distance.
To define ENERGY,
you also need to know what a FORCE is
and how to measure it.
A force is a PUSH or a PULL.
8 What about kilograms? A kilogram is technically a unit of mass and not a unit of force.

Before Isaac Newton, the concept of inertia didn't exist. So the distinction between mass and weight made no sense when the word was first introduced. And much of the world is stuck with it!

Your mass is the same throughout the universe. Your weight varies with gravity. On Earth it can vary by .7%. On the Moon your mass remains the same as it is on Earth. You are still made of the same amount of stuff, but you weight is six fold less. That is, if you weigh 60 pounds on earth, you weigh 10 pounds on the Moon!

And we are going back to the Moon! So this detail may matter to you -- if you plan to join in that adventure!
On to measuring FORCE with spring scales! Spring scales
are used to
the force of
a PUSH or a PULL.
You measure the PULL of gravity on your body with a bath scale.

We measure this PULL in pounds.
Click for answer.
9 Use a Spring Scale
to Measure Force
Find these items: soft plastic cup hole punch a small apple spring scale
10 Now you are ready to measure a FORCE! Punch a hole in the cup. Hold up the spring scale with the empty cup attached. Slide the paper scale
until the zero mark
lines up with the top of the yellow tube.
Hook the cup
to the paper clip
on your spring scale.
You just ZEROED the spring scale. 1 2 3 Now you are ready to measure a FORCE!
11 This is the weight of your apple in newtons.
Does it weigh more than one newton? Most apples do.
What number on the scale does the top of the yellow tube line up with? The gravity of the earth is PULLing down on the apple.
You are measuring the force of that PULL
with your spring scale.
Put the small apple into the cup.
Hold up the spring scale.
How could you make your apple weigh ONE newton? 4 5
12 Now use your spring scale to measure the PULL of gravity on what is left of your apple. Take a bite out of your apple, of course! 6 7 8 Now measure how many marbles, dominoes or pennies, it takes
to PULL down on the spring with the FORCE of ONE newton.
Be careful not to overstretch the spring on your scale. Keep nibbling on your apple
until it weights ONE NEWTON!
13 What is a Newton of Force? All forms of ENERGY
have the ABILITY to do WORK.
have to do with energy?
With distance and force
you can measure WORK.
WORK? Let's think this through. ENERGY
is the ABILITY
You know that you do “work”
when you do your chores
or your homework.
You might define work
as doing something
you don’t whole-heartedly want to do.
18 That is NOT what scientists mean by work.
How do scientists define work?
WORK happens
when a FORCE moves something
through a DISTANCE.
WORK takes place
when a FORCE moves
an object a DISTANCE.

Can you think of
ways you can do work?
20 You will need: Let's do a tiny bit of work. feather
or small
piece of paper
ruler Lift the feather
10 centimeters
off the table.
You have just performed a tiny bit of work on the feather. HOW? You applied a FORCE to lift the feather
a DISTANCE of 10 centimeters!
Place the feather
on the table.
21 Joule! One unit of measurement
for DISTANCE is a meter.

One unit of measurement
for a FORCE is a newton.

Is there a unit
of measurement
for work?
YES! It is called a JOULE!
A joule
is the amount of
work it takes
to lift a small apple
that weighs one newton
a DISTANCE of one meter.
22 Remember that apple core
that now weighs one newton?

Lift your munched apple
exactly one meter.
NOW, you have more
precisely accomplished
one joule of work!
23 NO! Zero distance
is NO distance at all.
Zero of anything is still zero!
Brain Teaser: if you push (a force) with all of your might on a wall
but the wall does not budge, have you performed any work on the wall?
Click for answer
Work takes place when a FORCE
moves an object a DISTANCE.
Work = Force x Distance You are learning about energy.
What does energy have to do with work
Click for answer ENERGY is the ABILITY to do work,
the ability to MOVE something
with a FORCE.
25 Work and Energy Eureka! Video 26 Be sure to add in players WHILE the cart is moving! Unbalanced Forces A Tug of War Your Screen Click on Electra
to begin.
27 Two major ideas
were presented
in this deceptively
simple simulation.

These ideas are SO profound,
they impact ALL of life:
Time to: PAUSE and THINK! ALL science, ALL politics and ALL relationships!
28 The constitution of the United States
was an attempt to achieve a balance
of powers, a balance of forces.
If we continue to strive to achieve that,
we are likely to get it right.
Throughout science,
if you ADD UP the forces,
the pushes and the pulls,
you are likely going to get it right.
It's always the SUM
of the forces that counts!
We leave relationships
for you to ponder.
How does this apply to science How might this apply to relationships How does this apply to governments
29 Did you discover that when the cart
was already in motion,
that adding in an EQUAL
force on the losing side,
did not slow down the cart!

If you did not try this,
go back and do it now.
Was it an error in the simulation
There was no error.
It was due to Newton's First Law of Motion:
An object in motion, tends to STAY in motion!

It takes MORE than
a balanced force to reverse course.
Ah, another one of those PROFOUND truths
for you to ponder.
All systems have INERTIA!
30 What is WORK What is ENERGY A force is a Are mass and
energy related
1 2 3 4 5 What is the unit for measuring WORK YES! E=mC2