1. Energy

2. What is Always Present But Never Visible?
Types and Forms of Energy
Gateway To Technology
Unit 3– Lesson 3.1– Investigating Energy
What is Always Present But Never Visible?
ENERGY
Although energy isn’t visible,
you can detect evidence of energy.

3. What is Energy? The ability to do work or cause change
Everything that happens in the world uses energy!
Most of the time we can’t see energy, but it is everywhere around us!

4. The Law of Conservation of Energy
The sun is the source of almost all the energy on earth.
The Law of Conservation of Energy
Energy cannot be created or destroyed; it may be transformed from one form into another, but the total amount of energy never changes.

5. Law of Conservation of Energy
Types and Forms of Energy
Gateway To Technology
Unit 3– Lesson 3.1– Investigating Energy
Law of Conservation of Energy
With every transformation, some energy is converted to less useful forms. Energy conversions are not 100% efficient. The energy output for the intended purpose is seldom the same as the energy we put in.
Energy in a system may take on various forms (e.g. kinetic, potential, heat, light). The law of conservation of energy states that energy may neither be created nor destroyed, but can change its form. Therefore the sum of all the energies in the system is a constant.
An incandescent light bulb is only 5% efficient as a lighting device. It would be more efficient as a heater! All of the energy remains, but a lot is converted to “waste” form.
95 J heat out
100 J electricity in
5 J light out

6. Types and Forms of Energy
Gateway To Technology
Unit 3– Lesson 3.1– Investigating Energy
Six Forms of Energy
Mechanical
Chemical
Electrical
Light/Radiant
Heat/Thermal
Nuclear

7. How is all energy divided?
Mechanical Energy
Potential
Energy
Kinetic
Energy
Gravitation
Potential
Energy
Elastic
Chemical

8. Potential Energy (PE)
The Energy due to its position. Energy that is stored. The snow on the mountain top represents potential energy.

9. Potential Energy
Potential energy is highest when the object is at a higher point, like this roller coaster on the top of a hill. The higher the hill the greater the potential energy.

10. Potential Energy
The more mass something has the greater its potential energy.

11. Kinetic Energy (KE)
The energy of motion
"Kinetic" means movement!

12. Kinetic Energy
The faster the motion the greater the kinetic energy. When the roller coaster starts down the hill it has kinetic energy. The point where the car is going the fastest is where the kinetic energy is the greatest.

13. Animated Roller Coaster

14. The faster the object moves, the more kinetic energy is produced.
The greater the mass and speed of an object, the more kinetic energy there will be.

15. When these objects move at the same speed, which will have more kinetic energy?

16. ANSWER
The semi- truck has more mass;
therefore, more kinetic energy!

17. Measuring Energy
Symbol for Energy = E
Unit of measure = Joule (J)
Because of the direct connection between energy and work, energy is measured in the same unit as work: joules (J).
In addition to using energy to do work, objects gain energy because work is being done on them.

18. Forms of Energy Energy can be found in many forms
Can be converted from one form or another
Conversion can be both man made and a natural process

19. Thermal Energy (a.k.a. Heat)
A special form of kinetic energy
Energy of moving or vibrating molecules
The faster the molecules vibrate the hotter they become
When heat is produced we have thermal energy.

20. Thermal Energy
Thermal Energy
Volcanoes can be a natural source of thermal energy. When we use the heat of the earth it is called geothermal energy.

21. Chemical Energy
Stored in chemical bonds holding the atoms of compounds together
Food, wood, batteries, fossil fuels

22. Chemical Energy When a chemical reaction takes place energy is used.
If energy is pulled in from the surrounding area during a chemical reaction, the area gets cold and the reaction is endothermic.
Commercial ice packs for injuries work this way.

23. Chemical Energy
When a chemical reaction takes place and releases energy it can increase the temperature. We call this an exothermic reaction.

24. Chemical Energy
Plants can make their own energy through a process called photosynthesis. They are the bases for a food chain. All other living things that cannot carry on photosynthesis depend on plants for their energy.

25. Energy Transformation
In photosynthesis radiant or light energy from the sun is changed to chemical energy in the leaf.

26. Chemical Energy
Other living things can get energy from eating plants or eating things that eat plants.

27. Chemical Energy
The energy we eat is stored as potential chemical energy until we need it. When we use the energy through an activity then it becomes kinetic mechanical energy.

28. Chemical Energy
Plants make food through the process of photosynthesis. When we use the energy from the chemical energy we store we break it down through a process called respiration. These are opposite energy reactions.

29. Electrical Energy Electrical Energy is the energy of moving Electrons
Electrical Energy is the energy of moving Electrons
Visible only when discharging
Electric Plants use huge generators that rotate magnets within coils of wire to produce electrical energy

30. Energy Transformation
Electrical energy can come from many different sources. Georgia's four existing nuclear reactor units accounted for 26% of the state's net electricity generation in 2015, coal accounted for 29%,natural gas accounted for 39%, and renewable energy, including hydroelectric power, contributed 6%

31. Sound Energy Sound energy is caused by an objects vibrations.
A form of potential and kinetic energy
To make an object vibrate, work must be done to change the objects position

32. Light Energy
Light Energy is produced by vibrations of electrically charged particles
Light vibrations cause energy to be transmitted
Vibrations that transmit light don’t cause other particles to vibrate

33. Our ultimate energy source is radiant energy from the sun
Our ultimate energy source is radiant energy from the sun H He + Energy

34. Nuclear Energy Energy stored in the nuclei of atoms
Energy stored in the nuclei of atoms
Released by fission, the splitting of nuclei of heavy atoms (ex: nuclear power plants)
Released by fusion-the combining of nuclei of light atoms (clean, ex: sun)
The energy released by fusion is
three to four times greater than
the energy released by fission.

35. Nuclear Energy
Einstein predicted the energy in a nuclear reaction before we had even split the atom in his famous equation:
E = m c2
E=energy, m = mass and c2 is the speed of light. He is basically saying if we take the mass of an object and multiply it by the speed of light that will tell us how much energy it contains. This did not make a lot of sense at the time.

36. Energy Basics There are many issues involved with energy.
Renewable vs. Nonrenewable
Energy Conservation
Environmental Concerns
Pollution
These are just a few of the things you can study when studying energy.

37. Mechanical Energy
Most familiar-involved with moving objects; atoms are moving and pushing each other
Sound is an example-occurs when atoms in a media vibrate in a direction outward from the sound source. Sometimes, sound is classified as its own energy source.

38. Mechanical Energy
When we move or work we are using mechanical energy.

39. Energy Transformations
Automobiles use chemical energy (fossil fuels) which is converted to mechanical energy when they move.

40. Elastic Energy
Energy stored in a solid object when it is either stretched or compressed.
A stretched rubber band, compressed spring or jack-in-the-box