# Conservation of Energy Where does energy come from? - PowerPoint PPT Presentation

PPT – Conservation of Energy Where does energy come from? PowerPoint presentation | free to download - id: 7d6f4c-ZTU5O

The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
Title:

## Conservation of Energy Where does energy come from?

Description:

### Conservation of Energy Where does energy come from? Changing Forms of Energy Energy is most noticeable as it transforms from one type to another. – PowerPoint PPT presentation

Number of Views:194
Avg rating:3.0/5.0
Slides: 24
Provided by: Palat45
Category:
Transcript and Presenter's Notes

Title: Conservation of Energy Where does energy come from?

1
Conservation of EnergyWhere does energy come
from?
2
Changing Forms of Energy
• Energy is most noticeable as it transforms from
one type to another.
• What are some examples of transforming electrical
energy?
• A lightbulb
• A hair dryer

3
Changing forms of Energy
• An example of transforming chemical energy is a
car engine. Chemical potential energy in
gasoline is transformed into kinetic energy of
the car as it moves!!

4
KE and PE
• In many situations, there is a conversion between
potential and kinetic energy.
• The total amount of potential and kinetic energy
in a system is called the mechanical energy
• Mechanical energy PE KE

5
Mechanical Energy
• Mechanical energy is due to the position and
motion of the object.
• What happens to the mechanical energy of an apple
as it falls from a tree?

6
Mechanical Energy
• As the apple falls to the ground, its height
decreases. Therefore, its GPE decreases.
• The potential energy is not lost it is converted
into kinetic energy as the velocity of the apple
increases.
• What happens to the mechanical energy?

7
Mechanical Energy
• The mechanical energy does not change because the
loss in potential energy is simply transferred
into kinetic energy.
• The energy in the system remains constant!!

The total amount of energy stays the SAME!!
8
Swinging Along
• Think about the changes in energy when you are on
a swing
• At what point do you have the most potential
energy?
• At what point do you have the most kinetic
energy?
• What happens to the mechanical energy?

9
The Law of Conservation of Energy
• The Law of Conservation of Energy states that
energy cannot be created or destroyed.
• The big picture the total energy in the universe
remains constant.

10
• But how? If I stop pumping while Im swinging, I
stop!! So, wheres the energy?
• Bill Nye -- Energy

11
Conservation of Energy
• You need to remember friction
• As you slow down on the swing, the hooks and the
chain rub against each other and air pushes
against the rider.

12
• Friction causes some of the mechanical energy of
the swing to change to thermal energy and the
temperature of the hooks and chain heat up a
little.
• The energy is still there, just in a different
form!!
• Bill Nye -- Friction

13
Conservation of Energy
• Energy is transformed not destroyed!!

The total amount of energy stays the SAME!!
14
• Even the energy converted in your body follows
the law of conservation of energy.
• Chemical potential energy is transferred to
kinetic energy that allows your body to move!!

15
Calories
• A Calorie (C) is a unit to measure energy in
foods.
• 1 Calorie is equal to about 4,184 Joules.
• 55 Calories while sleeping for 1 hour
• 210 Calories while walking for 1 hour
• 850 Calories while running for 1 hour

16
Is Perpetual Motion Possible?
• Why is perpetual motion not possible?
• Because energy conversions always result in the
production of waste thermal energy.

17
Non-renewable resources
• Define a non-renewable resource.
• A resource that forms at a rate that is much
slower than the rate at which it is consumed.
• What is a fossil fuel?
• Energy resources made from the buried remains of
plants and animals that lived millions of years
ago.

18
Nuclear Energy
• What is nuclear energy?
• Thermal energy that is obtained by splitting the

19
Renewable resources
• List the 5 types of renewable resources
• Solar
• Energy from water
• Wind
• Geothermal
• Biomass

20
Renewable resources
• Describe solar energy
• Changing sunlight into electrical energy through
solar cells
• Describe Energy from Water
• Dams block water, then lets it flow over turbines
to make energy.
• Hydroelectricity

21
Renewable resources
• Describe wind energy.
• Wind turns wind turbines that change the kinetic
energy of air into electrical energy us turning a
generator
• Describe Geothermal energy
• Water is pumped underground to hot rocks that
produces stream that turns the turbines of a
generator.

22
Renewable Resources
• Describe Biomass
• Burning plants, wood, and waste to create energy.
• What is fire?
• Coal Power Plant

23