Nature of EnergyNature of Energy

Energy is all around you!Energy is all around you! You can hear energy as sound.You can hear energy as sound. You can see energy as light.You can see energy as light. And you can feel it as wind.And you can feel it as wind.

Energy is usually described Energy is usually described as kinetic or potentialas kinetic or potential

Thermal or Heat EnergyThermal or Heat Energy

The internal motion of the The internal motion of the atoms is called heat energy, atoms is called heat energy, because moving particles because moving particles produce heat.produce heat.

Heat energy can be produced Heat energy can be produced by friction.by friction.

Heat energy causes changes in Heat energy causes changes in temperature and phase of any temperature and phase of any form of matter.form of matter.

Chemical EnergyChemical Energy Chemical Energy is required to bond atoms Chemical Energy is required to bond atoms

together.together. And when bonds are broken, energy is And when bonds are broken, energy is

released.released. Fuel and food are formsFuel and food are forms

of stored chemical energyof stored chemical energy

Electromagnetic EnergyElectromagnetic Energy Light is a form of electromagnetic energy.Light is a form of electromagnetic energy. Each color of light (Roy G Biv) represents a Each color of light (Roy G Biv) represents a

different amount of electromagnetic energy.different amount of electromagnetic energy. Electromagnetic Energy is also carried by X-rays, Electromagnetic Energy is also carried by X-rays,

radio waves, and laser light.radio waves, and laser light.

Electromagnetic SpectrumElectromagnetic SpectrumIncreasing Energy

Electromagnetic Electromagnetic EnergyEnergy

Power lines carry Power lines carry electromagnetic energy into your electromagnetic energy into your home in the form of electricity.home in the form of electricity.

Nuclear EnergyNuclear Energy The nucleus of an atom is the source of The nucleus of an atom is the source of

nuclear energy. nuclear energy. When the nucleus splits (fission), nuclear When the nucleus splits (fission), nuclear

energy is released in the form of heat energy energy is released in the form of heat energy and light energy.and light energy.

Nuclear energy is also released when nuclei Nuclear energy is also released when nuclei collide at high speeds and join (fuse).collide at high speeds and join (fuse).

Nuclear Power PlantNuclear Power Plant

Nuclear EnergyNuclear Energy

The sun’s energy is produced from a nuclear fusion reaction in which hydrogen nuclei fuse to form helium nuclei.

Mechanical EnergyMechanical Energy

Mechanical energy is due to Mechanical energy is due to the position and motion of the position and motion of the object.the object.

When work is done to an When work is done to an object, it acquires energy. object, it acquires energy. The energy it acquires is The energy it acquires is known as mechanical known as mechanical energy.energy.

Mechanical EnergyMechanical Energy

What happens to the mechanical What happens to the mechanical energy of an apple as it falls from a energy of an apple as it falls from a tree?tree?

Mechanical EnergyMechanical Energy As the apple falls to the ground, its height As the apple falls to the ground, its height

decreases. decreases. Therefore, its GPE decreases.Therefore, its GPE decreases. Potential Potential

energy that is dependent on height is called energy that is dependent on height is called gravitational potential energygravitational potential energy..

The potential energy is not lost… it is The potential energy is not lost… it is converted into kinetic energy as the velocity of converted into kinetic energy as the velocity of the apple increases.the apple increases.

What happens to the mechanical energy?What happens to the mechanical energy?

Mechanical EnergyMechanical Energy

The mechanical energy does not change The mechanical energy does not change because the loss in potential energy is because the loss in potential energy is simply transferred into kinetic energy.simply transferred into kinetic energy.

The energy in the system remains The energy in the system remains constant!!constant!!

Swinging AlongSwinging Along

Think about the changes in energy when Think about the changes in energy when you are on a swing…you are on a swing…

At what point do you have the most At what point do you have the most potential energy?potential energy?

At what point do you have the most At what point do you have the most kinetic energy?kinetic energy?

What happens to the mechanical What happens to the mechanical energy?energy?

Conservation of EnergyConservation of Energy Energy is transformed… not destroyed!!Energy is transformed… not destroyed!!

The Law of Conservation of Energy

• The law of conservation of energy states that energy cannot be created or destroyed.

• Energy can be changed from one form to another. Changes in the form of energy are called

energy conversions.

Energy Conversion Energy Conversion ExamplesExamples

The Law of Conservation of Energy

• Even when energy changes form from electrical to thermal and other energy forms as in the hair

dryer shown energy is never destroyed.

The Law of Conservation The Law of Conservation of Energyof Energy

The Law of Conservation of Energy The Law of Conservation of Energy states that energy cannot be created or states that energy cannot be created or destroyed.destroyed.

The big picture… the total energy in the The big picture… the total energy in the universe remains constant.universe remains constant.

Changing Forms of Changing Forms of EnergyEnergy

Energy is most noticeable as it Energy is most noticeable as it transforms from one type to another.transforms from one type to another.

What are some examples of transforming What are some examples of transforming electrical energy?electrical energy? A lightbulbA lightbulb A hair dryerA hair dryer

The most common energy The most common energy conversion is between potential conversion is between potential and kinetic energy.and kinetic energy.

All forms of energy can be in either All forms of energy can be in either of two states:of two states:Kinetic is the energy of motion.Kinetic is the energy of motion.Potential is stored energyPotential is stored energy

Potential to KineticPotential to Kinetic

Changing forms of Changing forms of EnergyEnergy An example of transforming chemical An example of transforming chemical

energy is a car engine. energy is a car engine. Chemical potential energy in gasoline is Chemical potential energy in gasoline is

transformed into kinetic energy of the car transformed into kinetic energy of the car as it moves!!as it moves!!