Energy

Defenitions

Energy = The ability to make things happen. Measured in Joules (J)

Kinetic energy = Energy an object has because it is moving.

Potential energy = Stored energy.

Chemical potential energy = Energy stored in chemicals. E.g. Petrol, candle wax, chemicals in batteries.

Elastic potential energy = Energy stored in rubber and springs. E.g. rubber ball, rubber band, slinky.

Electrical energy = Energy flowing along wires. Electrical circuits.

Gravitational potential energy = Stored energy an object has when it is up high above the ground.

Light energy = Organized vibrational energy in a light wave. E.g. sunlight, torch light.

Sound energy = Organized vibrational energy that is in a sound wave.

Thermal energy = Disorganized (random) vibrational energy that atoms have (Heat).

Input energy = Energy put into a device of situation to cause change.

Output energy = Energy form(s) that come out of an energy transformation or situation.

Useful energy = Energy that has been produced in an energy transformation that was desirable.

Waste energy = Energy that has been produced in an energy transformation that was undesirable.

Energy efficiency = A percentage (%) representing what portion of the of the original energy has been converted into the new desirable form of energy.

Energy transfer = When energy is moved from one object onto another object(s).

Energy transformation = When an original form of energy is converted into different forms of energy.

Atom = Building block of matter. (Smallest particle of matter that has the properties of an element)

Electron = Negatively charged piece of an atom.

Charge = A characteristic of a material that expresses the extent to which it has more or fewer electrons than protons

Current = The rate of flow of charge in a circuit

Conductor = A material that permits the flow of electricity through it.

Insulator = A material that does not permit the flow of electricity through it.

Series circuit = A single path circuit

Parallel circuit = A circuit multiple path circuit

Electric Motor = A device that produces movement from electrical energy

Active Wire = A wire which carries electrons with energy

Neutral Wire = A wire which carries electrons with no energy

Earthed Wire = A wire which diverts electrons to the ground (rather than through the person)

Fuse = Thin wire that melts and breaks the circuit when too many electrons flow through it in a short period of time

Circuit breaker = A device which breaks the circuit when too many electrons flow through it in a short period of time

Earth Leakage Protection Device (or Safety Switch) = A device that breaks the circuit when it detects a different number of electrons travelling through the live/neutral wire in the same period of time

Double insulated = An appliance with two layers of insulation around the active wire

⚡ ENERGY & ELECTRICITY — NOTES THAT ACTUALLY WORK

🔋 1. Energy = “the ability to make things happen”

That’s it. That’s the whole idea.

Everything else is just types of energy or what energy is doing.

🧠 2. Two MAIN types (burn this into your brain)

🏃 Kinetic Energy = movement

  • If it’s moving, it has kinetic energy

  • Examples:

    • Running person

    • Rolling ball

    • Flowing water

👉 Memory trick:
“Kinetic = kinetic = moving chaos”

🪫 Potential Energy = stored energy

  • If it’s waiting to move, it has potential energy

  • Examples:

    • Stretched rubber band

    • Object held up high

    • Fuel before it burns

👉 Memory trick:
“Potential = has potential to do something later”

🔥 3. Types of Energy (group them or suffer)

Don’t memorise randomly. Group them:

📦 STORED ENERGY (Potential)

  • Chemical → stored in substances (fuel, batteries)

  • Elastic → stretched/squashed (rubber band)

  • Gravitational → height above ground

👉 Shortcut:
“CEG = stored energy gang”

🌊 MOVING / TRANSFER ENERGY

  • Electrical → energy moving through wires

  • Light → energy in light waves

  • Sound → energy in sound waves

  • Thermal → heat (random movement of particles)

👉 Shortcut:
“ELST = energy on the move”

🔄 4. Energy NEVER disappears (important)

Energy just:

  • Transfers (moves place)

  • Transforms (changes type)

🔁 Energy Transfer

Energy moves object → object
Example: bat hits ball

🔄 Energy Transformation

Energy changes form
Example:

  • Battery → electrical → light (torch)

👉 Core idea:
Energy in = Energy out (just different forms)

💀 5. Useful vs Waste Energy (real life is inefficient, like humans)

  • Useful energy = what you actually want

  • Waste energy = wasted (usually heat or sound)

Example:

  • Light bulb:

    • Useful → light

    • Waste → heat

📊 6. Efficiency (how “good” something is)

  • Measures how much useful energy you get

  • Always a percentage (%)

👉 Memory:
High efficiency = less wasted energy

⚛ 7. Atoms (tiny but important)

Everything = atoms

Inside atoms:

  • Electrons → negative charge ⚡

  • Movement of electrons = electricity

⚡ 8. Electricity Basics (don’t overcomplicate it)

Current

  • Flow of electrons

  • Basically: how fast charge moves

Charge

  • Whether something has more or fewer electrons

🔌 9. Conductors vs Insulators

Conductors

  • Let electricity flow

  • Example: metals

Insulators

  • Block electricity

  • Example: plastic, rubber

👉 Memory:
“Conductor = conducts (lets it pass)”

🔁 10. Circuits (this matters A LOT)

Series Circuit

  • ONE path

  • If one thing breaks → everything stops

👉 Think: Christmas lights dying all at once

Parallel Circuit

  • MULTIPLE paths

  • One breaks → others still work

👉 Think: normal house wiring

⚙ 11. Wires (this part saves lives, so maybe remember it)

  • Active wire → carries energy

  • Neutral wire → carries energy back

  • Earth wire → safety path to ground

🚨 12. Safety Devices (aka “don’t die” tech)

Fuse

  • Melts if too much current

  • Breaks circuit

Circuit Breaker

  • Switches off automatically

Safety Switch (ELPD)

  • Detects imbalance → shuts off

Double Insulated

  • Extra protection

  • No earth wire needed