Energy Notes

Energy is…..The ability to do work

OR

The ability to move an object using a force

There are two types of energy….

Potential Energy

Kinetic Energy

Potential Energy

Stored energy; energy of position

the stored ability to move matter

GravityThe energy of a place or position

Examples:

● apple hanging in a tree

● ball held at top of roof

ElasticEnergy stored in an object by the application of a

force

Examples:

● stretched rubber band

● compressed spring

MagneticAttraction or repulsion of magnets

Examples:

● needle on compass

● magnets on fridge

Chemical

Energy stored in bonds

Examples:

● gasoline

● food

Nuclear

Energy stored in the nucleus of an atom

Examples:

Energy in the nucleus

of a uranium atom

ElectrostaticAttraction or repulsion

of electric charges

Examples:

● clothes sticking together out of dryer

● going down plastic slide then touching metal

Kinetic Energy

Energy of motion; waves, electrons, atoms,

molecules and substances

MechanicalEnergy of an object in motion that

depends on mass and velocity

Examples:

● car moving

● riding a bike

ThermalEnergy within a substance

due to the kinetic energy

of its molecules/atoms

As thermal energy increases, the

particles of a substance separate

Examples: ice melting, water boiling

Electrical

Movement of electrons

Examples:

● light bulb

● lightening

Sound

Vibrations that pass through an object and

travel in waves

Examples:

● radio playing music

● hearing thunder

ElectromagneticEnergy that is reflected or emitted

from an object in the form of

electric or magnetic waves

Examples:

● light

● rainbow

Law of Conservation of Energy

Energy is not created or destroyed, only

transformed or transferred

What it means: We have the same amount of matter and energy in the universe now that has always existed, they just keep changing from one form to another.

Observations

Baseball Observations:The energy has changed forms:

● vibrations of molecules of air: we perceive as sound● vibrations of molecules of glass: destroyed the glass● vibrations of molecules of glass and ball: heat generated● energy transferred to the glass shards and they move or

fly through the air

Overall:No energy was lost, it just changed forms or was transformed

Transforming energy causes “things” to happen and to change

Law of Conservation of Matter/Mass

Mass/Matter can not be created or

destroyed, only changed

Observations:

Observations:● Fire/flames ● Smoke● Changes in wood● Ashes● Hear crackling/popping● Afterwards: “less” of the wood

The matter changed forms● Water vapor● CO2 gas● Sulfur and nitrogen compounds in gaseous form● Pure carbon left in ash● Particles of incompletely burned wood go “up”

Collect it allIf we measured the mass before and could collect all of the

“pieces” afterwards the mass would be almost equal.

The missing mass would have turned into energy: heat energy.

Energy TransferEnergy stays in the same form but passes from one

object to another

Examples: dominoes, heating a pot of water

Energy TransformationEnergy changes into different

forms; can occur within an object

or between objects

Example: moving car

(gas - engine - tires)

Conservation of Mass and Energy

Neither one is created or destroyed, ever!

Can transform into new forms or into the the other.

Einstein moment: E = mc2 His equation is all about the “equivalency” of matter and energy

E (energy) = mass x constant2 (speed of light, 186,000 m/sec)