Understanding Energy and the Law of Conservation

• Energy refers to the ability to do work resulting in the change and movement of objects.
• The unit of measure for energy is the Joule (J).
• Energy adheres to the Law of Conservation of Energy.
• Examples of energy include cooking food, driving to school, and jumping.

Law of Conservation of Energy

• Energy can neither be created nor destroyed.
• Energy can be transformed or transferred.
• During energy transformation, energy converts from one type to another, such as electrical energy becoming light energy in a torch.
• No energy is lost during transformation.
• Energy can be transferred from one object to another.
• No energy is lost during the transfer process.

Types of Energy

• Energy can be classified as either potential or kinetic.
• Potential energy is the energy related to an object's position.
• Potential energy is not easily observed until it is transformed.
• Kinetic energy is the energy of a moving object.
• Kinetic energy is easily observed in forms like light, sound, and thermal energy.

Different Types of Energy

• Gravitational energy is stored within an object's height.
• The higher and heavier the object, the more gravitational energy is stored (e.g., apple falling from a tree).
• Elastic energy is stored in objects under tension (e.g., compressed springs).
• Chemical energy is stored in the bonds of atoms and molecules (e.g., biomass).
• Nuclear energy is stored in the nucleus of an atom and can generate huge amounts of energy through combining and splitting atoms (e.g., medical diagnostics).
• Electrical energy is delivered by electrons, typically through a wire (e.g., lighting).
• Magnetic energy is stored in magnets or metals placed in a magnetic field (e.g., electric motors).
• Heat/Thermal energy comes from the movement of atoms and molecules in a substance (e.g., the Sun).
• Light (Radiant) energy is released when an object is hot (e.g., sunlight).
• Sound energy is caused by vibrations through a substance in waves (e.g., talking).

Potential Energy

• Potential energy can result from stretching or squashing an object.
• It can also be the energy of lifting an object above the ground.
• The separation of unlike charges is another form of potential energy.

Gravitational Potential Energy (GPE)

• The amount of GPE depends on mass, height above ground, and gravitational field strength.
• GPE (joules) = mass (kg) x change in height (m) x gravitational field strength (N/kg).
• Gravitational field strength is always 9.8N/Kg or 10N/Kg.

Elastic Potential Energy

• An object gains or loses elastic potential energy when its shape is changed (e.g., slingshot).
• The more a rubber band is stretched, the more elastic potential energy it gains.

Chemical Potential Energy

• Chemical potential energy exists when the chemicals inside an object have the potential to react (e.g., food).
• Food and drinks release stored chemical energy to our bodies.
• A chemical reaction takes place when the two terminals of a battery are connected, resulting in the flow of electricity.

Electrical Potential Energy

• All substances consist of positive and negative charges.
• As charges come together, they release their electrical potential energy.
• In an electrical circuit, stored electrical potential energy is released to the connecting wires and components.

Magnetic Potential Energy

• Magnetic fields provide magnetic potential energy.
• Magnets when held in attraction have potential energy.
• When released the magnetic potential energy accelerates them together.

Nuclear Potential Energy

• Nuclear potential energy is stored in the nucleus of atoms.
• A huge amount of energy has the potential to be released if the nuclei can be made to split or combine.
• Nuclear reactions include fission, fusion, nuclear decay, and transmutation.

Kinetic Energy (KE)

• Kinetic energy is the energy of a moving object.
• Translational kinetic energy, such as a person walking, depends on the object's mass and speed or velocity.
• The heavier an object and the faster it travels, the more translational kinetic energy it possesses.

Thermal Energy

• Thermal energy is commonly known as heat, the transfer of thermal energy from hotter to cooler objects.
• Thermal energy transfer can occur through the movement of particles in solids, liquids, or gases.
• Thermal energy transfer can also occur through radiation, even without particles.

Radiant Energy

• Radiant energy is the energy of electromagnetic waves.
• Radiant energy includes visible light, x-rays, and microwaves.
• Radiant energy is a form of kinetic energy because waves carry radiation from one source to another.

Sound Energy

• Sound involves the vibration of particles in the air (or another medium).
• Sound is a form of kinetic energy.
• A sound source causes nearby particles in the air to vibrate.

Electrical Energy

• Electrical energy can be a form of both potential and kinetic energy.
• Electricity, the movement of electric charges through a circuit, is a form of kinetic energy.