Electricity powers our lives

APES 2024

Watts

Watts

the absolute meter-kilogram-second unit of power equal to the work done at the rate of one joule per second

Filament

a thin piece of carbon or metal that allows energy to flow through a conductor and glows with intense heat

The internet and all our computers use about

5% of global electricity

20% of global electricity is just

lighting

Every day the average American uses

a 100,000 watt-hours times (over 300 million of us)

Simply taking a shower uses

thousands of watts

A hybrid car uses

a combination of gasoline and electric power

Examples of energy

light, heat, sound, and motion

2 main types of energy

potential & kinetic

Potential energy

stored energy and the energy of position, or gravitational potential energy (several forms)

Chemical energy

stored in the bonds of atoms and molecules, it holds these particles together (ex. biomass, petroleum, natural gas, propane, and food)

Elastic energy

stored in objects by the application of a force (ex. compressed springs & stretched rubber bands)

Nuclear energy

stored in the nucleus of an atom, it is the energy that holds the nucleus together, the energy can be released when the nuclei are combined or split apart

Nuclear power plants split the nuclei of uranium atoms in a process called

fission

The sun combines the nuclei of hydrogen atoms in a process called

fusion

Gravitational potential energy

the energy of position or place, a rock resting at the top of a hill contains gravitational potential energy because of its position (ex. Hydropower, such as water in a reservoir behind a dam)

Kinetic energy

is motion; it is the motion of waves, electrons, atoms, molecules, substances, and objects

Electrical energy

is the movement of electrons (ex. lightning)

Everything is made of

atoms

What 3 smaller perticles make up atoms?

protons, electrons, & neutrons

Applying a force can make

some of the electrons move

Electricity

electrons moving through a wire

Radiant energy

is electromagnetic energy that travels in vertical (transverse) waves (ex. visible light, x-rays, gamma rays, radio waves, & solar energy)

Thermal energy

the internal energy in substances; it is the vibration and movement of the atoms and molecules within a substance (ex. geothermal energy)

The more thermal energy in a substance, the

faster the atoms and molecules vibrate and move

Motion energy

is the movement of objects and substances from one place to another (ex. wind)

Objects and substances move when an unbalanced force is applied according to

Newton’s Laws of Motion

Sound energy

is the movement of energy through substances in longitudinal (compression/rarefaction) waves

Sound is produced when a force causes an object or substance to

vibrate; the energy is transferred through the substance in a longitudinal wave

Energy conservation is not just about

saving energy

Law of Conservation of Energy

energy is neither created nor destroyed

When we use energy, it doesn’t disappear. We change one form of energy into another ex.

• a car engine burns gasoline, changes the chemical energy in gasoline into motion energy

• solar cells change radiant energy into electrical energy

Energy changes form, but

total amount of energy in the universe stays the same

Energy transformations

• chemical —> motion

• radiant —> chemical

• electrical —> thermal

Energy efficiency

the amount of useful energy you get from a system

A perfect, energy efcient machine would

change all the energy put in it into useful work—a technological impossibility today

Converting one form of energy into another form always involves a

loss of usable energy

Most energy transformations are

not very efficient (ex. the human body)

Most of the energy in your body is transformed and released as

thermal energy

Electricity is diferent from the other energy sources because it is a

secondary source of energy (another energy source must be had to produce electricity)

The number one energy source used for generating electricity in the US

natural gas

Electricity is sometimes called an energy carrier because

it is an efcient and safe way to move energy from one place to another, and it can be used for so many tasks

As we use more technology,

the demand for electricity grows

U.S. Energy Consumption by Source, 2017

Nonrenewable - 88.4%

• Petroleum 37.0% Uses: transportation, manufacturing - Includes Propane Biomass 5.2% Uses: electricity, heating, transportation

• Natural Gas 28.7% Uses: electricity, heating, manufacturing - Includes Propane Geothermal 0.2% Uses: electricity, heating

• Coal 14.1% Uses: electricity, manufacturing

• Uranium 8.6% Uses: electricity

• Propane Uses: heating, manufacturing

U.S. Energy Consumption by Source, 2017

Renewable 11.4 %

• Biomass 5.2% Uses: electricity, heating, transportation

• Hydropower 2.8% Uses: electricity

• Geothermal 0.2% Uses: electricity, heating

• Wind 2.4% Uses: electricity

• Solar 0.8% Uses: electricity, heating