Energy Stores: Kinetic, Potential, and Chemical

• Energy stores and their uses exist in physics

Kinetic Energy

• Kinetic energy is the energy an object possesses due to its motion
• Kinetic energy is used when objects move, such as cars, rivers, or birds
• It plays a vital role in transportation and energy generation, including wind turbines

Gravitational Potential Energy

• Gravitational potential energy is energy stored in an object due to its position in a gravitational field
• This energy is utilized when an object is lifted, like a book on a shelf
• It can transform into kinetic energy when the object falls, like in a waterfall or pendulum

Elastic Potential Energy

• Elastic potential energy is energy stored in an object when it is stretched or compressed, like in a spring
• This energy is used in systems such as bows and arrows or spring-loaded toys
• The stored energy releases when the object returns to its original shape

Chemical Energy

• Chemical energy is energy stored in the bonds of chemical compounds, like food or fuel
• It's used in chemical reactions, such as when fuel burns in an engine or when the body metabolizes food

Thermal Energy (Heat Energy)

• Thermal energy is the total kinetic energy of particles in a substance
• It's used in heating systems, cooking, and industrial processes
• It can also be harnessed to produce electricity in power plants via steam turbines

Nuclear Energy

• Nuclear energy is energy stored in the nucleus of an atom
• This energy is released during nuclear reactions, such as in nuclear power plants or the sun
• Nuclear fusion produces vast amounts of energy

Electrostatic Energy

• Electrostatic energy is energy stored due to the position of charged particles relative to each other
• This energy is used in devices like capacitors, where energy is stored in electric fields, or in lightning

Magnetic Energy

• Magnetic energy is energy stored in a magnetic field created by moving electric charges or magnetic materials
• It is used in motors and generators for converting energy and in magnetic storage devices like hard drives
• In MRI machines and maglev trains, it facilitates lifting and propulsion

Conservation of Energy

• The unit of energy is the joule (J)
• Energy is conserved
• Energy cannot be created nor destroyed
• Energy transforms from one form to another
• The total amount of energy in a closed system remains constant

Energy Transfers

• Electrical to Light Energy (light bulbs): Electrical energy converts into light energy, with heat as a byproduct.
• Chemical to Kinetic Energy (car engines): Fuel's chemical energy converts into kinetic energy to move the car, with heat and sound as waste.
• Kinetic to Electrical Energy (generators): Mechanical motion converts into electrical energy in turbines.
• Thermal to Mechanical Energy (steam engines): Heat energy turns into steam, which moves pistons or turbines to do mechanical work.
• Gravitational Potential to Kinetic Energy (roller coasters): Height-based potential energy turns into kinetic energy as the roller coaster moves down.
• Electrical to Sound Energy (speakers): Electrical signals move a diaphragm to create sound vibrations.
• Solar to Electrical Energy (solar panels): Solar energy converts into electrical energy for electrical devices.

Non-Useful Energy Transfers

• All energy transfers are partly non-useful, because energy is lost to the surroundings as waste energy, usually as heat or sound.
• The loss happens due to inefficiencies in the system

Useful energy transfers

• Electrical to Light (light bulbs): Useful as light; non-useful as heat.
• Chemical to Kinetic (car engines): Useful for motion; non-useful as heat and sound.
• Kinetic to Electrical (generators): Useful as electricity; non-useful as heat/friction.
• Solar to Electrical (solar panels): Useful as electricity; non-useful due to inefficiency.
• Thermal to Mechanical (steam engines): Useful for work; non-useful as heat.
• Gravitational to Kinetic (roller coasters): Useful for motion; non-useful as heat (friction).

Non-Useful energy transfers

• Electrical to Heat (appliances): Energy wasted as heat.
• Friction (moving parts): Kinetic energy wasted as heat.
• Sound Energy (engines): Sound is wasted energy.