Section 1: What is Section 1: What is energy?energy?

Definition:Definition:

Energy is the capacity to do work.Energy is the capacity to do work.

Energy is not a “thing”. Something has energy Energy is not a “thing”. Something has energy when it can achieve something, for example when it can achieve something, for example move, glow, make a sound.move, glow, make a sound.

Sources of EnergySources of EnergyWe get our ability to do things from our food. We get our ability to do things from our food. Our food is our source of energy.Our food is our source of energy.

A fire gets its ability to do something A fire gets its ability to do something (that is, heat other things up or burn (that is, heat other things up or burn things) from the wood. The wood is things) from the wood. The wood is the source of the energy.the source of the energy.

Plants make their food by Plants make their food by photosynthesis. The energy they photosynthesis. The energy they need comes from the Sun.need comes from the Sun.

Ultimately, the Ultimately, the Sun is the Sun is the source of source of energy for energy for everything on everything on Earth.Earth.

Forms of EnergyForms of Energy

For example, an object which can For example, an object which can affect other objects because of its affect other objects because of its movement is said to have kinetic movement is said to have kinetic energy. (Kinetic is a word from energy. (Kinetic is a word from Greek which means movement)Greek which means movement)

An object which can affect other An object which can affect other objects because it gives off light is objects because it gives off light is said to have light energy.said to have light energy.

The The formform of the energy is the way that the of the energy is the way that the ability to do something is produced in an ability to do something is produced in an object.object.

More Forms of EnergyMore Forms of Energy

Some things can’t affect anything yet, but are Some things can’t affect anything yet, but are storing up the ability to affect something. storing up the ability to affect something.

For example, food sitting on a table cannot do For example, food sitting on a table cannot do any work yet, but if you eat it, you will gain any work yet, but if you eat it, you will gain energyenergy

So we say food has So we say food has potentialpotential energy. energy.

Types of Potential EnergyTypes of Potential Energy

Chemical potential energyChemical potential energy- Will be able to do something because of the chemicals - Will be able to do something because of the chemicals it containsit contains

Gravitational potential energyGravitational potential energy- will be able to do something because it is above the - will be able to do something because it is above the ground and can fallground and can fall

Elastic potential energyElastic potential energy- will be able to do something because it is wound up or - will be able to do something because it is wound up or stretched and will spring back when released.stretched and will spring back when released.

Some Forms of EnergySome Forms of Energy

MechanicalMechanical

Chemical potentialChemical potential

NuclearNuclear

SoundSound

Heat (thermal)Heat (thermal)

LightLight

ElectricalElectrical

Elastic potentialElastic potential