1. Unit 2 Lesson 1 Introduction to Energy

2. Get Energized! What is energy?
Unit 2 Lesson 1 Introduction to Energy
Get Energized!
What is energy?
Energy is the ability to cause change and do work.
Energy takes many different forms and causes many different effects.
There are two general types of energy: kinetic energy and potential energy.

3. What are two types of energy?
Unit 2 Lesson 1 Introduction to Energy
What are two types of energy?
Kinetic energy is the energy of an object that is due to motion. All moving objects have kinetic energy.
The amount of kinetic energy an object has depends on its mass and speed.
Kinetic energy increases as mass increases and as speed increases.
The smallest particles of matter have kinetic energy because they are in constant, random motion. This motion can contribute to the thermal energy of a substance, depending on how fast the particles are moving.

4. A bowling ball will have more kinetic energy than a soccer ball because it has more mass.
With 2 bowling balls of the same mass, the one moving faster will have more kinetic energy.

5. What are two types of energy?
Unit 2 Lesson 1 Introduction to Energy
What are two types of energy?
Potential energy is the energy that an object has due to its position, condition, or chemical composition.
Potential energy is stored until it is changed into kinetic energy.
A change in the condition of an object affects its potential energy. Stretching a rubber band increases its potential energy.
Potential energy that is the result of an object’s position is called gravitational potential energy.
Gravitational potential energy increases as the object’s height or mass increases.

6. A roller coaster car moving to the top of the track.
The same roller coaster rolling down the track.
Which scenario is an example of increasing potential energy?
Which scenario is an example of increasing kinetic energy?

7. A B C D
On which platform would a diver have the greatest gravitational potential energy?

8. Objects can have potential and kinetic energy at the same time.
Unit 2 Lesson 1 Introduction to Energy
Objects can have potential and kinetic energy at the same time.
An object can have both potential and kinetic energy at the same time.
A skater has kinetic energy as he/she moves down a half-pipe and potential energy due to his/her position on the ramp.
His/her potential energy decreases and his/her kinetic energy increases as he/she rolls down the side.
His/her potential energy increases and his/her kinetic energy decreases as he/she rolls up the other side.

9. Minimum Kinetic energy
Maximum Potential energy
Minimum Kinetic energy
Maximum Potential energy
Kinetic energy increases
Potential energy decreases
Kinetic energy decreases
Potential energy increases
Maximum Kinetic energy
Minimum Potential energy

10. Energy can take different forms
Unit 2 Lesson 1 Introduction to Energy
Energy can take different forms
Kinetic energy and potential energy can come in many different forms.
Some common forms of energy include mechanical, sound, electromagnetic, electrical, chemical, thermal, and nuclear energy.
Energy is expressed in Joules (J).

11. Unit 2 Lesson 1 Introduction to Energy
Chemical energy
Chemical energy is a form of potential energy that is stored in the chemical bonds between atoms.
Chemical potential energy depends on chemical composition (arrangement of atoms).
As bonds break and new bonds form between atoms during a chemical change, energy can be released.
Example: When a chemical change (reaction) occurs, the original bonds are broken and new bonds are formed. In an exothermic change, some of the chemical energy is transformed and released as thermal energy.

12. Unit 2 Lesson 1 Introduction to Energy
Mechanical energy
Mechanical energy is the sum of an object’s kinetic energy and potential energy. It is the energy of position and motion.
The movement of your muscles and the parts in a machine are examples of mechanical energy.
Sound energy is kinetic energy caused by the vibration of particles in a medium such as steel, water, or air.

13. Electromagnetic Energy
Unit 2 Lesson 1 Introduction to Energy
Electromagnetic Energy
Electromagnetic energy is transmitted through space in the form of waves.
These waves are caused by the vibration of electrically charged particles.
Examples of electromagnetic energy:
Radio waves
Infrared “rays” from heat lamps
Microwaves
Ultraviolet rays
X-rays
Chemical changes
The light given off when wood burns

14. Chemical and physical changes can be CAUSED by electromagnetic energy.
Example: Microwaves can change a frozen block of sauce back into a liquid, a physical change.

15. Electromagnetic Energy
1 : 45
Magnetron
Electromagnetic Energy
Thermal Energy

16. Unit 2 Lesson 1 Introduction to Energy
Electrical Energy
Electrical energy is the energy that results from the position or motion of electrically charged particles.
Electrons moving from one atom to another in a chemical change is an example of electrical energy.
Electrolysis involves electrical energy.
Electrolysis involves placing 2 metal strips (electrodes) attached to wires in a solution without letting them touch. When the wires are attached to a electrical source, atoms on one electrode can lose electrons and the atoms on the other electrode can gain electrons, creating new substances.

17. Unit 2 Lesson 1 Introduction to Energy
Thermal Energy
Thermal energy is the kinetic energy of an object’s particles.
The faster the molecules in an object move, and the more particles the object has, the more thermal energy it has.
Heat is the energy transferred from an object at a higher temperature to an object at a lower temperature.

18. Nuclear Energy Fission Fusion
Unit 2 Lesson 1 Introduction to Energy
Nuclear Energy
The nucleus of an atom is the source of nuclear energy.
When an atom’s nucleus breaks apart (fission), or when the nuclei of two small atoms join together (fusion), A great amount of energy is released.
Fission
Fusion

19. Transformers Energy Transformation
Unit 2 Lesson 1 Introduction to Energy
Transformers
Energy Transformation
An energy transformation takes place when energy changes from one form into another form.
Any form of energy can change into any other form of energy.
Often, one form of energy changes into more than one form.

20. Energy Transformation
Unit 2 Lesson 1 Introduction to Energy
Energy Transformation
In a flashlight, chemical energy is transformed into electrical energy.
The electrical energy is then transformed into electromagnetic and thermal energy. 20

22. Mechanical Energy and Moves Piston and Car
Electrical Energy
EXHAUST
FUEL
Chemical Energy
Changes to
Thermal Energy
Thermal Energy
Changes to
Mechanical Energy and Moves Piston and Car

23. VI. Energy Transformations in a pendulum
In a pendulum, a continuous transformation between kinetic and potential energy takes place
At the highest point in the swing the pendulum has no kinetic energy (no movement) so it only has gravitational potential energy
As it swings downward its speeds up and its potential energy is transformed into kinetic energy
At the bottom of the swing, the pendulum reaches its maximum speed since this is where all its energy becomes kinetic energy

24. Minimum Kinetic Energy Minimum Kinetic Energy
Greatest Potential Energy
Minimum Kinetic Energy
Greatest Potential Energy
Minimum Kinetic Energy
Greatest Kinetic Energy
Minimum Potential Energy

25. When does the transfer of energy take place in this object?

26. Energy Transformation
During a chemical change, chemical energy may be changed into other forms of energy:
Burning fuel is a chemical change that transforms chemical energy into thermal and electromagnetic energy.
Pushing a bike up a hill transforms the chemical energy from the food you ate into mechanical kinetic energy of your moving muscles.

27. Energy Transformation
Other forms of energy may also be changed into chemical energy:
During photosynthesis, plants transform electromagnetic energy from the sun into chemical energy making molecules of sugar.
The chemical energy from plants becomes the energy needed to carry out life activities when eaten.

28. Energy and Friction
As a top spins it is affected by friction from the floor and friction from the air
When a moving object experiences friction, some of its kinetic energy is transformed into thermal energy
The mechanical energy of the spinning top is also transformed to thermal energy
The top slows down and eventually falls on its side
The top’s energy is not destroyed – it is transformed

29. Mechanical Energy
Thermal Energy
Air Friction
Floor Friction

30. How is energy conserved?
Unit 2 Lesson 1 Introduction to Energy
How is energy conserved?
A closed system is a group of objects that transfer energy only to one another. Energy is conserved in all closed systems.
The law of conservation of energy states that energy cannot be created or destroyed. It can only change forms.
All of the different forms of energy in a closed system always add up to the same total amount of energy.

31. Calculating Velocity, Potential and Kinetic Energy
Unit 2 Lesson 1 Introduction to Energy
Calculating Velocity, Potential and Kinetic Energy
To calculate potential energy, multiply the mass of the object (in kg) by the height it fell, or will fall (in m) and then multiply the result by 9.8.
To calculate kinetic energy, first square the velocity (velocity X velocity), then multiply that number by the mass of the object (in kg), and finally divide by 2.
All energy is shown in Joules (J).
To calculate velocity, multiply the fall time (in seconds) of the object by 9.8.