This document discusses the nature and forms of energy. It defines energy as the ability to do work and identifies five main forms: mechanical, heat, chemical, electromagnetic, and nuclear. Mechanical energy is associated with motion and includes kinetic and potential energy. Kinetic energy is the energy of motion, while potential energy is stored energy due to an object's position or state. The document provides examples of energy conversions, including the conversion between kinetic and potential energy. It introduces the law of conservation of energy, which states that energy cannot be created or destroyed, only changed from one form to another.

1. NATURE OF ENERGY
CATAPULT DESIGN/MOUSE TRAP
COMPETITION

2. I. What is Energy??
A. Energy Basics
1. Energy can be defined as the ability to do work.
a. An example of work would be an object/organism
exerting a force over a distance to move an a
object….therefore the object uses energy.
b. Electric charges in a current use energy as they move
along a wire(we discussed this!!!)
c. Energy can be measured in joules (J)… which is the
same unit used to measure work.

3. 2. In addition to objects using energy to do
work, objects can energy because work is
being done on them.
a. If work is done an object, energy is given to that
object.
b. If you fling a ping pong ball with a
mousetrap…you give the ping pong ball energy
to make it move.

4. II. Forms of Energy
A. Five main forms of Energy
1. Mechanical
2. Heat
3. Chemical
4. Electromagnetic
5. Nuclear

5. B. Mechanical Energy
1. Energy associated with motion is called
mechanical energy.
a. Water in a waterfall has great mechanical energy!!!
b. Other examples include wind, automobiles, walking,
swimming, blood flowing through your veins and
LAUNCHING PING PONG BALLS from a mousetrap!!!
c. **Sound is also a type of mechanical energy…sound
waves move mechanically!!

6. C. HEAT ENERGY
1. Internal motion of ATOMS is called heat energy.
a. All matter is made up of atoms that are constantly moving.
2. The faster the particles move…the more heat energy
is produced.
a. Using the friction between your hands….when you rub your
hands together…you take the mechanical energy
(movement of hands) and convert it into heat energy.
3. Heat energy usually results from friction.
4. Heat energy causes changes in temperature and may
cause change in phase (solid to liquid, liquid to
gas..etc. )

7. D. Chemical Energy (Think Bombs!!)
1. Energy exists in the bonds that hold atoms together.
2. This energy is called chemical energy.
3. When bonds are broken this energy is released.
4. When fuel is burned, chemical energy is released and
converted into heat energy.
5. Digestion of food is another example of chemical
energy
6. When you exercise (mechanical Energy) your body
needs the chemical energy stored in your muscles.

8. E. Electromagnetic Energy
1. Power lines carry electromagnetic energy into
our homes in the form of electricity.
2. Each color in visible light (ROYGBIV) is
electromagnetic energy.
a. Each color represents a different amount of energy.
3. X-Rays, Microwaves, Infra-red, ultraviolet, and
Gamma Rays are also examples.

9. F. Nuclear Energy
1. The nucleus or center of the atom contains NUCLEAR
ENERGY.
2. When the nucleus splits, nuclear energy is released
in the form of heat and light energy.
a. This is called fission and is the main principal of nuclear
reactors.
3. Nuclear energy is also released then lightweight
nuclei collide at high speeds and fuse (join).
a. This is like the forming of the sun and called fusion.
b. We cannot duplicate fusion.

10. QEUSTIONS YOU WILL NEED TO
KNOW!
1. What is energy?
2. Can energy be transferred from one object to
another? Explain (give examples)
3. What are the different forms of energy?
4. Why is energy measured in the same unit as
work?

11. II. Kinetic Energy and Potential Energy
1. Two STATES of energy are potential and
kinetic.
a. Our example will be a set mouse trap (or
catapult).
b. If you take your finger and hold the mousetrap
back without setting it….even though the mouse
trap is not moving there is a form of energy at
rest keeping that mousetrap in that position……

12. 2. Kinetic Energy
a. The energy of motion is called kinetic energ
b. Because the object is in motion it has the ability to
do work….hence the term energy.
c. Kinetic comes form the Greek root for movement.
d. The faster an object moves the more kinetic energy
it has.
e. If the same person is runs for 2 miles, then crawls for
2 miles…when do they have the most kinetic energy?

13. 3. Do all objects have the same kinetic energy?
a. Kinetic energy depends upon the mass and the
velocity (speed with direction).
b. The mathematic relationship between kinetic energy
(K.E.), mass, and velocity is:
c. 퐾. 퐸. = (푚푎푠푠 × 푣푒푙표푐푖푡푦2) ÷ 2
d. According to this equation, an increase in either
mass or velocity will mean an increase in kinetic
energy.
e. Which of these factors will have a greater affect on
kinetic energy?? Why???

14. 4. POTENTIAL Energy
a. Potential energy is the energy of position, or
energy at rest.
b. The mousetrap that is set…but not moving has
zero kinetic energy…but it does have potential
energy.
c. The chemical energy stored in food is also
considered potential energy….give two more
examples!!!

15. 5. Gravitational Potential Energy
a. Potential energy that is dependent on height is
called gravitational potential energy.
i. Waterfalls, suspension bridges, even a mouse trap
raised to a different height and snowflakes have
gravitational potential energy.
b. Weight also determines the amount of
gravitational potential energy an object has.
i. “The bigger they are, the harder they fall” is an
observation of the effect of weight on gravitational
potential energy.

16. 6. How to determine Gravitational Potential
Energy
a. The relationship between gravitational potential
energy (G.P.E.), weight, and height can be
expressed in the following formula:
b. 퐺. 푃. 퐸. = 푊푒푖푔ℎ푡 푋 퐻푒푖푔ℎ푡
c. The greater the weight the greater the GPE
d. The greater the position above the surface, the
greater the GPE.

17. 1. What is kinetic energy? Potential Energy?
a. Energy of motion, energy of position.
2. Use the formula for kinetic energy to describe
the relationship between the kinetic energy of
an object, its mass, and its velocity.
a. KE is equal to ½ the product of mass times square of
velocity.
3. What is gravitational potential energy? How is it
calculated?
a. Potential energy due to height above ground; PE
equals weight times height.

18. III. Energy Conversions
A. Kinetic-Potential Energy Conversions
1. One of the most common energy conversions involves
the changing of potential energy to kinetic energy or
kinetic to potential.
2. Throwing a ball from rest up into the air is a great
example.
a. Ball has all potential at the start.
b. You give it kinetic energy.
c. As the ball rises is slows down, so its kinetic decreases and
potential increases. (because it height increases)
d. At the top the ball is stopped!!! It now only has potential energy.
e. As the ball falls it speeds up, loses potential and gains kinetic.

19. B. Other conversions
1. All forms of energy can be converted to other
forms.
a. Solar energy can be used as heat energy, light energy,
chemical energy (photosynthesis),and converted into
electricity.
b. Electric motors: electromagnetic energy is converted
to mechanical energy.
c. Battery: chemical energy is converted to
electromagnetic energy.

20. III. Things to know!!!
1. Describe the conversions between potential
and kinetic energy as a tennis ball drops, hits
the ground, and bounces back up.
a. Before the ball drops all of its energy is potential.
As it falls, potential energy is converted into
kinetic energy. When it hits the ground its
kinetic energy is at the maximum. Then as it
bounces back up, kinetic energy is converted into
potential.

21. III. Things to know!!!
2. What energy conversions take place in a
pendulum? Why does the pendulum
eventually stop?
a. A pendulum converts potential energy into
kinetic energy as it swings down, and kinetic
energy into potential energy as it swings up. As
it swings, it loses energy to friction caused by the
particles of air and by the apparatus holding the
top of the pendulum. Thus, it eventually slows
down and stops.

22. III. Things to know!!!
3. Describe the energy conversions that you
think take place when a flashlight is turned
on.
a. Chemical energy in the batteries is converted
into electromagnetic energy in the form of a
current. The current is then converted into light.

23. IV. Conservation of Energy
A. Law of Conservation of Energy
1. Energy can be neither created nor destroyed by
ordinary means.
2. Energy can only be converted from one form to
another.
3. Energy is never lost, even when one form of
energy is converted to another.

24. B. Albert Einstein
1. 1905: According to Einstein even the tiniest
mass can form a tremendous amount of energy.
2. Einstein’s theory of relativity deals with the
concept that mass and energy are DIRECTLY
related.
3. Einstein believes that mass and energy can be
converted into each other. (deep….really deep
thoughts!!)

25. B. Albert Einstein
4. With this relationship Einstein clarified the LAW of
conservation of energy.
5. He showed that if matter is destroyed, energy is
created and if energy is destroyed, matter is created.
6. The total amount of mass and energy is conserved
7. Mass is continuously changed to energy in our SUN
through a process called nuclear fusion.
a. During fusion a small loss in mass produces a HUGE amount
of energy!!!

26. Think about this……
1. What is the law of conservation of energy?
a. Energy can neither be created or destroyed by
ordinary means.
2. How does the law of conservation of energy
relate to energy conversions?
a. Energy conversions involve changes in the forms
of energy. They occur without the loss or gain of
energy.

27. Think about this……
3. Using the law of conservation of
energy…..Explain why you become pushing a
shopping cart 3 miles?
a. Energy is neither created nor destroyed, you
must be giving your energy to the cart. As you
give up your energy (both chemical and
mechanical) your muscles become tired.