--- title: "Energy" description: "54 topics in Science, in the order they build on each other." canonical: https://lightmysky.com/learn/science/areas/energy source: https://lightmysky.com/learn/science/areas/energy.md retrieved: 2026-10-19 --- > **Agent view.** This is the Markdown twin of the page, for tools and assistants. > When to use this site, and the call that answers each job: https://lightmysky.com/agent-instructions.md > API description (OpenAPI 3.1): https://lightmysky.com/openapi.json · Authentication: https://lightmysky.com/auth.md > Pricing: https://lightmysky.com/pricing.md · Catalog: https://lightmysky.com/llms.txt · Full catalog: https://lightmysky.com/llms-full.txt > Every machine-readable file on this domain: https://lightmysky.com/.well-known/ai-catalog.json > Ask for Markdown with `Accept: text/markdown`, a `.md` address, or `?mode=agent`. # Energy 54 topics in Science, in the order they build on each other. Page: https://lightmysky.com/learn/science/areas/energy - [Sunlight warms things up](https://lightmysky.com/learn/science/sunlight-warms-things-up-mt_iGSfQg3g5c): Make observations to determine the effect of sunlight on Earth's surface, noticing that sunlight warms the ground, water, and objects - [Naming types of energy](https://lightmysky.com/learn/science/naming-types-of-energy-mt_akBotspaf2): Name kinetic, potential, chemical, thermal, light, sound and electrical energy in familiar situations. Describe energy transfer from one object or place to another, and energy transformation from one type to another. - [What uses electricity at home](https://lightmysky.com/learn/science/what-uses-electricity-at-home-mt_9nxyFoYD_b): Identify common appliances that run on electricity and understand that electricity is a form of energy that powers devices in everyday life - [Building a simple circuit](https://lightmysky.com/learn/science/building-a-simple-circuit-mt_DA7-JYRvtP): Construct a simple series electrical circuit, identifying and naming its basic parts: cells, wires, bulbs, switches, and buzzers - [Conductors and insulators](https://lightmysky.com/learn/science/conductors-and-insulators-mt_d-EKO-pKkP): Recognise some common conductors and insulators, and associate metals with being good conductors of electricity - [Will the bulb light up?](https://lightmysky.com/learn/science/will-the-bulb-light-up-mt_NNNbPccwB4): Identify whether or not a lamp will light in a simple series circuit, based on whether the lamp is part of a complete loop with a battery - [How switches work](https://lightmysky.com/learn/science/how-switches-work-mt_Hah24nbToi): Recognise that a switch opens and closes a circuit, controlling whether a lamp lights or a buzzer sounds - [Circuit vocabulary](https://lightmysky.com/learn/science/circuit-vocabulary-mt_NzCNuABT3E): Use technical vocabulary for electrical circuits — circuit, component, cell, battery, current, voltage, resistance, conductor, insulator, switch, series circuit, parallel circuit — and apply these when describing, drawing, and designing working circuits - [Reading and drawing circuit diagrams](https://lightmysky.com/learn/science/reading-and-drawing-circuit-diagrams-mt_loYPGHJ8lm): Draw and read simple circuit diagrams using standard symbols for cells, bulbs, switches, buzzers, and wires; identify whether a circuit is complete or broken from a diagram; match circuit diagrams to physical circuits - [How energy travels around](https://lightmysky.com/learn/science/how-energy-travels-around-mt_X_aDUBh-HF): Observe and provide evidence that energy can be transferred from place to place by sound, light, heat, and electric currents - [Building an energy-converting device](https://lightmysky.com/learn/science/building-an-energy-converting-device-mt_K1-HopEJAB): Apply scientific ideas to design, test, and refine a device that converts energy from one form to another - [More batteries, brighter bulb](https://lightmysky.com/learn/science/more-batteries-brighter-bulb-mt_vFT_GbkP9m): Associate lamp brightness or buzzer volume with the total voltage from cells connected in series, while keeping the component within its rated range. - [Why circuit components behave differently](https://lightmysky.com/learn/science/why-circuit-components-behave-differently-mt_-QY08-88rw): Compare and give reasons for variations in how circuit components function, including brightness of bulbs, loudness of buzzers, and switch positions - [Drawing circuits with proper symbols](https://lightmysky.com/learn/science/drawing-circuits-with-proper-symbols-mt_NzNLYDb9CZ): Use standard circuit symbols and straight wire lines to represent cells, bulbs, switches, buzzers and motors, then read what the diagram shows. - [Current, voltage, and what they measure](https://lightmysky.com/learn/science/current-voltage-and-what-they-measure-mt_2bnXrfS4Iq): Understand current as charge flow rate and voltage as energy transferred per unit charge, then connect each quantity to its meter and circuit connection. - [Static electricity and sparks](https://lightmysky.com/learn/science/static-electricity-and-sparks-mt_2_YoprauaJ): Explain static electricity as the build-up of electric charge through friction, describe how charged objects attract or repel each other, and relate static discharge to everyday phenomena such as lightning - [Ohm's Law: voltage, current, resistance](https://lightmysky.com/learn/science/ohms-law-voltage-current-resistance-mt_H3ZDK0EYNV): Apply Ohm's Law (V = IR) to calculate current, voltage, or resistance in a simple circuit, and explain that resistance opposes the flow of current - [Series vs parallel circuits](https://lightmysky.com/learn/science/series-vs-parallel-circuits-mt_loEMaQ8kFA): Describe and apply the rules for current, voltage, and resistance in series and parallel circuits, and explain the practical uses of each circuit type - [Current-Voltage Graphs for Components](https://lightmysky.com/learn/science/current-voltage-graphs-for-components-mt_n_CiOa-05J): Measuring current against potential difference for a fixed resistor, a filament lamp and a diode, then reading each graph's shape. A straight line means constant resistance, and a bend means the resistance is changing. - [Resistance in Series and Parallel](https://lightmysky.com/learn/science/resistance-in-series-and-parallel-mt_B29m3h5B75): Resistances in series add. Adding a working parallel branch lowers total resistance and raises supply current when supply voltage stays the same. Predictions can be checked with measurements in a supervised low-voltage circuit. - [Thermistors, Light-Dependent Resistors and Sensing Circuits](https://lightmysky.com/learn/science/thermistors-light-dependent-resistors-and-sensing-circuits-mt_d92v1CiqIG): A thermistor's resistance falls as it warms and a light-dependent resistor's falls as light on it rises, so either one placed in a potential divider turns a physical change into a changing voltage. That voltage is what a heating controller or a street light switches on. - [Resistivity and What Sets a Wire's Resistance](https://lightmysky.com/learn/science/resistivity-and-what-sets-a-wires-resistance-mt_A4f8THP-xm): A wire's resistance grows with its length and falls with its cross-section, and dividing out both leaves a number belonging to the material alone. That number is why copper is used for cables and why a strain gauge works at all. - [Speed and energy](https://lightmysky.com/learn/science/speed-and-energy-mt_2Um22lTBZV): Use evidence to construct an explanation relating the speed of an object to the energy of that object - [What happens when things collide](https://lightmysky.com/learn/science/what-happens-when-things-collide-mt_1MLi55bPnt): Ask questions and predict outcomes about the changes in energy that occur when objects collide - [Energy stores and transfers](https://lightmysky.com/learn/science/energy-stores-and-transfers-mt_Jvg_r4yWaY): Identify kinetic, gravitational potential, elastic potential, thermal, chemical, nuclear, magnetic and electrostatic energy stores. Describe transfers mechanically, electrically, by heating and by radiation, distinguishing stores from transfer pathways. - [Energy can't be created or destroyed](https://lightmysky.com/learn/science/energy-cant-be-created-or-destroyed-mt_68pIoiiG4g): Explain the principle of conservation of energy (energy cannot be created or destroyed, only transferred between stores), and describe how energy is dissipated as thermal energy to the surroundings in all real processes - [Power: watts and energy per second](https://lightmysky.com/learn/science/power-watts-and-energy-per-second-mt_ckpA3oZQ44): Define power as the rate of energy transfer (power = energy ÷ time, measured in watts), and compare energy transfer rates in different everyday contexts - [Electrical Power and the Cost of Running Appliances](https://lightmysky.com/learn/science/electrical-power-and-the-cost-of-running-appliances-mt_099G0drIbk): Power in a circuit is potential difference times current, and also current squared times resistance. Energy transferred is power times time, which is what the kilowatt-hour on an electricity bill counts. - [Electromotive Force, Internal Resistance and the Potential Divider](https://lightmysky.com/learn/science/electromotive-force-internal-resistance-and-the-potential-divider-mt_g3zYJ9qC53): A real source has resistance of its own, so the voltage across its terminals drops as it delivers more current and the missing part heats the source. Two resistors across a supply share that voltage in the ratio of their resistances, which is how a fixed supply is turned into whatever voltage a circuit needs. - [Efficiency, Sankey diagrams, and work done](https://lightmysky.com/learn/science/efficiency-sankey-diagrams-and-work-done-mt_JyfLtl_nhw): Calculate energy efficiency as the ratio of useful output energy to total input energy, construct and interpret Sankey diagrams, and calculate work done using work = force × distance - [Heating experiments and Q = mcΔT](https://lightmysky.com/learn/science/heating-experiments-and-q-mc-t-mt_DI1cyAyGyN): Plan and carry out experiments to measure energy transferred during heating, including using the equation Q = mcΔT, recording temperature changes over time, and evaluating sources of error - [Calculating work done and power](https://lightmysky.com/learn/science/calculating-work-done-and-power-mt_udulQxseg1): Calculate work done by a constant force along an object's motion in joules. Calculate average mechanical power as work divided by time in watts, and distinguish work by a specified force from changes in energy stores. - [Kinetic and gravitational potential stores](https://lightmysky.com/learn/science/kinetic-and-gravitational-potential-stores-mt_uD3jklaZCw): Calculate kinetic energy from mass and speed, and gravitational potential energy from mass, gravitational field strength and height. Use ideal drops and straight-up launches to find speeds and rise heights, with negligible resistance. - [Specific Heat Capacity as a Material Property](https://lightmysky.com/learn/science/specific-heat-capacity-as-a-material-property-mt_mXC9IKom3P): Specific heat capacity is a number belonging to a material, and rearranging Q = mc times temperature change turns it into predictions. It explains storage heaters, why water is used as a coolant, and why the sea warms slowly. - [Internal Energy, Absolute Zero and the Kelvin Scale](https://lightmysky.com/learn/science/internal-energy-absolute-zero-and-the-kelvin-scale-mt_n4Ku8ZDy1U): Internal energy is the total kinetic and potential energy of the particles in a body, counted over their random motion rather than the motion of the body as a whole. Absolute zero is where that random kinetic energy is as low as it can go, and the kelvin scale starts there. - [Specific Heat Capacity and Specific Latent Heat in Calculations](https://lightmysky.com/learn/science/specific-heat-capacity-and-specific-latent-heat-in-calculations-mt_GKNPAJgroW): Warming a substance takes m c delta theta, while changing its state takes m L with no temperature change at all. A heating curve is read as a run of these two calculations taken in order. - [Work Done by a Force at an Angle](https://lightmysky.com/learn/science/work-done-by-a-force-at-an-angle-mt_OvBtur6dW5): Only the part of a force along the displacement does work, which gives W = Fs cos theta. A force at right angles to the motion, such as the string tension on a whirled object, does none at all. - [Power as Force Times Velocity, and Efficiency](https://lightmysky.com/learn/science/power-as-force-times-velocity-and-efficiency-mt_2FFGLIjgV6): Dividing work by time when the force is steady gives P = Fv, which reads power straight off a speed. Efficiency then compares the useful output with the total input for the same machine. - [Electromagnetic induction and generators](https://lightmysky.com/learn/science/electromagnetic-induction-and-generators-mt_e0jgUKANT-): Explain how a changing magnetic field through a coil induces voltage and can drive current in a closed circuit. Describe mechanical input to generators, current reversal in a simple AC generator, and Faraday's experiments. - [Conduction, convection, and radiation](https://lightmysky.com/learn/science/conduction-convection-and-radiation-mt_ySnOkVIu22): Describe and compare the three mechanisms of heat transfer — conduction (particle vibration through solids), convection (fluid movement in liquids/gases), and radiation (infrared waves) — and explain that the rate of transfer depends on temperature difference - [Renewable vs non-renewable energy](https://lightmysky.com/learn/science/renewable-vs-non-renewable-energy-mt_w2A8D76ymp): Distinguish renewable resources, including solar, wind, hydroelectric, tidal, geothermal and replenished biomass, from non-renewable fuels such as coal, oil, gas and uranium. Compare cost, reliability and environmental impacts. - [Building shade from the sun](https://lightmysky.com/learn/science/building-shade-from-the-sun-mt_2agkUcdah9): Use tools and materials to design and build a structure that will reduce the warming effect of sunlight on an area, such as a shade or shelter - [Work as a Line Integral Along a Path](https://lightmysky.com/learn/science/work-as-a-line-integral-along-a-path-mt_UFuQUPGAt7): When force varies along the route, work is the integral of the force component along the displacement rather than a product. The work-energy theorem then follows from the equation of motion instead of being quoted. - [Conservative Forces and the Potential Energy Function](https://lightmysky.com/learn/science/conservative-forces-and-the-potential-energy-function-mt__053R9wrQy): A force whose work depends only on the endpoints defines a potential energy, and the force is recovered as minus the derivative of that function. Friction fails the test, which is why no friction potential exists. - [Potential Energy Curves, Turning Points and Stability](https://lightmysky.com/learn/science/potential-energy-curves-turning-points-and-stability-mt_ZgRbrDaQzh): A plot of potential energy against position tells the whole story of one-dimensional motion: turning points where the curve meets the total energy, and minima that are stable equilibria. The curvature at a minimum sets how fast small oscillations run. - [Mains Electricity: a.c., Earthing and Fuses](https://lightmysky.com/learn/science/mains-electricity-a-c-earthing-and-fuses-mt_jKTotBL78P): Mains supply is alternating, changing direction many times a second, unlike the direct current from a cell. The live, neutral and earth wires each have a job, and a fuse or breaker cuts the circuit when the current climbs too high. - [Transformers and the National Grid](https://lightmysky.com/learn/science/transformers-and-the-national-grid-mt_ExV4Kc_7_P): A transformer uses a changing magnetic field to raise or lower an alternating voltage, in the ratio of the turns on its two coils. The grid steps voltage up for transmission because a smaller current wastes less energy heating the cables. - [Static Charge and Electric Fields](https://lightmysky.com/learn/science/static-charge-and-electric-fields-mt_6ii6CVOTI5): Rubbing moves electrons between surfaces, leaving one negative and the other positive, and like charges push apart. Around any charge is a field, and a strong enough field makes the air itself conduct, which is the spark. - [Coulomb's Law and the Electric Field of a Point Charge](https://lightmysky.com/learn/science/coulombs-law-and-the-electric-field-of-a-point-charge-mt_p7FuzIsQch): Two point charges push or pull with a force that also falls off as the inverse square, but this one comes with two signs. Field strength is the force per coulomb on a small positive test charge. - [Electric Potential and the Uniform Field Between Plates](https://lightmysky.com/learn/science/electric-potential-and-the-uniform-field-between-plates-mt_LKTfeYxNde): Between parallel plates the field is uniform and equals V over d, so a charge crossing the gap gains energy QV. Around a point charge the potential is kQ over r, and it takes the sign of the charge. - [Capacitance and the Energy Stored in a Capacitor](https://lightmysky.com/learn/science/capacitance-and-the-energy-stored-in-a-capacitor-mt_j1Eltr9z6l): Capacitance is the charge a component holds per volt across it. Because the charge builds as the voltage rises, the stored energy is half of QV, the area under the charge-voltage line. - [Discharging a Capacitor and the Time Constant](https://lightmysky.com/learn/science/discharging-a-capacitor-and-the-time-constant-mt_5sjDPudyad): A capacitor discharging through a resistor loses charge at a rate set by the charge still on it, so voltage, charge and current all fall exponentially. The product RC is the time taken to fall to about 37 per cent. - [Magnetic Flux, Flux Linkage and Faraday's Law](https://lightmysky.com/learn/science/magnetic-flux-flux-linkage-and-faradays-law-mt_ZoN5JePCpt): For a uniform field, flux through a flat loop is B A cos theta, with theta measured from the loop normal. Flux linkage is N times the flux. Signed induced emf is the negative rate of linkage change; its magnitude is the absolute value. - [Lenz's Law and the Alternating-Current Generator](https://lightmysky.com/learn/science/lenzs-law-and-the-alternating-current-generator-mt_69u-fTOSku): An induced emf has the direction that opposes the change in magnetic flux. In a closed resistive coil it drives a current with that effect. An ideal planar coil rotating at constant angular speed about an axis in its plane and perpendicular to a uniform magnetic field produces a sinusoidal emf.