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Secundaria Ages 11-13
Go deeper: algebra, physics, coding, nature and longer reads.
➗ Matemáticas
📐Angles in a TriangleDiscover why the angles in a triangle always add up to 180°, how to find a missing angle, the exterior angle rule, and i📐Area and PerimeterLearn area and perimeter the clear way: the difference between them, formulas for rectangles, squares and triangles, uni⭕Circles: Circumference and AreaLearn the parts of a circle and master circumference and area using pi: clear formulas, full worked examples, the radius🔄Converting Fractions, Decimals and PercentagesConvert between fractions, decimals and percentages with confidence: clear rules for every direction, a handy conversion🧭Coordinates in Four QuadrantsPlot and read coordinates in all four quadrants using positive and negative x and y values. Learn the quadrant signs, th🔢Decimals ExplainedUnderstand decimals clearly: place value of tenths and hundredths, reading and comparing decimals, and adding, subtracti➗Dividing FractionsMaster dividing fractions with the keep-change-flip method: multiply by the reciprocal, simplify, and divide whole and m📦Expanding BracketsLearn to expand brackets in algebra using the distributive law. Step-by-step worked examples with negative signs, two br🔢Exponents and PowersMaster exponents and powers: what a base and exponent mean, squares and cubes, the laws of exponents, the power of zero,⚖️InequalitiesUnderstand inequalities: read the four symbols, solve one- and two-step inequalities, plot solutions on a number line, a🍰Introduction to FractionsUnderstand fractions clearly: numerators and denominators, equivalent fractions, comparing and simplifying, plus worked ➖Introduction to Integers (Negative Numbers)Meet the integers: positive and negative whole numbers. Learn the number line, absolute value, and the rules for adding,📈Line GraphsA middle-school math lesson on line graphs: plot points, read values, interpret trends and gradients, handle two lines, 📊Mean, Median, Mode and RangeMaster the four key statistics: learn to calculate mean, median, mode and range step by step, when to use each one, and ✖️Multiplying FractionsMaster multiplying fractions: multiply tops, multiply bottoms, simplify, and handle whole and mixed numbers. Worked exam🔢Number Sequences and the nth TermLearn to find the nth term rule of a linear sequence. Step-by-step worked examples: find the common difference, build th🧮Order of Operations (BODMAS/PEMDAS)Master the order of operations with BODMAS and PEMDAS: brackets, indices, division, multiplication, addition and subtrac%Finding a Percentage of an AmountLearn to find a percentage of an amount three ways: using 10% and 1% building blocks, fractions, and decimal multipliers🏷️Percentages in Real Life (Discounts and Tax)Use percentages in everyday situations: work out discounts, sales prices, sales tax and VAT, tips, and percentage increa💯Percentages Made EasyMaster percentages step by step: what percent means, finding a percent of a number, percentage increase and decrease, an🥧Pie ChartsA middle-school math lesson on pie charts: read sectors, work out angles and percentages, draw your own pie chart, find ⚖️Ratio and Proportion ProblemsMaster ratio and proportion word problems: sharing amounts, scaling recipes, map scales, unit rates, and the unitary met⚖️Ratios and ProportionsUnderstand ratios and proportions: how to write and simplify a ratio, find equivalent ratios, scale recipes, and solve p🔄Rotation and TranslationLearn two key transformations: rotation (turning a shape about a centre by an angle) and translation (sliding a shape). 🧹Simplifying ExpressionsLearn to simplify algebraic expressions by collecting like terms. Step-by-step worked examples covering signs, multiple ⚖️Solving Equations with BracketsLearn to solve linear equations that contain brackets. Step-by-step worked examples: expand, collect like terms, balance🧮Solving Two-Step EquationsLearn to solve two-step equations the reliable way: undo operations in reverse order, keep both sides balanced, handle n🟦Square Numbers and Square RootsUnderstand square numbers and square roots: how squaring works, perfect squares, finding and estimating roots, and where🔁Substituting into FormulasLearn to substitute numbers into algebraic formulas. Step-by-step worked examples with brackets, powers, negative number📦Surface Area and VolumeLearn surface area and volume of cubes, cuboids, prisms and cylinders with clear formulas and full worked examples, plus📈The Coordinate PlaneLearn the coordinate plane: the x-axis and y-axis, the origin, ordered pairs (x, y), the four quadrants, and how to plot⭕Venn Diagrams and SetsLearn Venn diagrams and sets: what a set is, union and intersection, the universal set and complement, reading overlappi✍️Writing Algebraic ExpressionsLearn to turn words into algebra: choose a variable, translate phrases like 'three more than' or 'twice a number', and w
⚛️ Física
⚖️Balanced and Unbalanced ForcesA middle-school physics lesson on balanced and unbalanced forces: resultant force, free-body diagrams, how unbalanced fo🤸Centre of Mass and BalanceA middle-school physics lesson on centre of mass and balance: what the centre of mass is, how to find it, why an object 🔥Conduction, Convection and RadiationA middle-school physics lesson on the three ways heat travels: conduction, convection and radiation. Worked examples, re🦇Echoes and UltrasoundA middle-school physics lesson on echoes and ultrasound: how sound reflects, how to calculate distance from echo time, w🔌Electricity Basics: Circuits and CurrentA middle-school physics lesson on electricity: electric charge, current, voltage, resistance, series and parallel circui♻️Energy Efficiency and TransfersA middle-school physics lesson on energy transfers and efficiency: conservation of energy, useful vs wasted energy, Sank⚡The Many Forms of EnergyA middle-school physics lesson on forms of energy: kinetic, potential, thermal, chemical, electrical, light and sound, e🛞Friction: The Force That Slows Things DownA physics lesson on friction for ages 9-13: learn what friction is, why surfaces grip, how lubricants and drag work, whe🔥Heat and How It TravelsA middle-school physics lesson on heat: temperature vs heat energy, and the three ways heat travels — conduction, convec🔍How Lenses WorkA middle-school physics lesson on how lenses work: convex and concave lenses, refraction, focal length, real and virtual🏭How We Generate ElectricityA middle-school physics lesson on generating electricity: turbines, generators and electromagnetic induction, fossil fue🪙Levers and MomentsA middle-school physics lesson on levers and moments: the law of the lever, the principle of moments, pivots, effort and🪝Measuring Forces with SpringsA middle-school physics lesson on measuring forces with springs and newton-meters: Hooke's law, F = kx, the elastic limi🛰️Orbits and SatellitesA middle-school physics lesson on orbits and satellites: how gravity keeps moons and satellites in orbit, why they don't🛢️Pressure and HydraulicsA middle-school physics lesson on pressure and hydraulics: the pressure formula, why pressure spreads through liquids, P🌊Pressure in Liquids and GasesA middle-school physics lesson on pressure in fluids: what pressure is, why it increases with depth, atmospheric pressur🔋Series and Parallel CircuitsA middle-school physics lesson on series and parallel circuits: how current, voltage and brightness behave in each, work🏃Speed, Distance and TimeA middle-school physics lesson on speed, distance and time: the speed formula, average vs instantaneous speed, units, di⭐The Life Cycle of StarsA middle-school physics lesson on the life cycle of stars: how stars are born in nebulae, shine by nuclear fusion, and d⚛️The Particle Model of MatterA middle-school physics lesson on the particle model of matter: tiny moving particles, how they explain solids, liquids ✈️The Physics of FlightA middle-school physics lesson on how planes fly: the four forces of flight (lift, weight, thrust, drag), how wings make🪐The Solar System and GravityA middle-school physics lesson on the solar system and gravity: the Sun, planets, orbits, why we have day and night and ⚡Voltage, Current and ResistanceA middle-school physics lesson on voltage, current and resistance and how Ohm's law links them. Worked V=IR examples, th〰️Wavelength, Frequency and AmplitudeA middle-school physics lesson on wavelength, frequency and amplitude: what each wave property means, the wave equation 🌊Waves and VibrationsA middle-school physics lesson on waves and vibrations: transverse and longitudinal waves, wavelength, frequency, amplit⚖️Weight vs MassA middle-school physics lesson on the difference between weight and mass: why mass stays the same everywhere, how weight
🌿 Naturaleza
🧪Acids and BasesAcids and bases explained for middle-school students: the pH scale, how acids and bases react, neutralisation, indicator⚛️Atoms and MoleculesAtoms and molecules explained for middle-school students: protons, neutrons and electrons, elements and the periodic tab🔬Cells: The Building Blocks of LifeCells explained for students: the smallest unit of life, plant vs animal cells, the parts of a cell and their jobs, how 🌋Earthquakes and TsunamisEarthquakes and tsunamis explained for middle school: how tectonic plates cause earthquakes, how seismic waves are measu🦅Food Chains and EcosystemsUnderstand food chains, food webs and ecosystems: producers, consumers, predators and decomposers. Real examples, energy🌌Galaxies and the Milky WayGalaxies and the Milky Way explained for ages 11-14: what a galaxy is, the shape and size of our Milky Way, spiral, elli🦇How Caves FormHow caves form, explained for middle school: solution caves dissolved by acidic water, stalactites and stalagmites, sea 🌀Hurricanes and TornadoesCompare hurricanes and tornadoes: how each forms, why they spin, how scientists measure them, real-world examples, safet🌊Natural Disasters: Floods, Droughts and StormsNatural disasters explained for students: what causes floods, droughts and storms, why they happen, how scientists predi🌿Photosynthesis ExplainedPhotosynthesis explained for middle school: how plants use sunlight, water and carbon dioxide to make glucose and oxygen⚡Renewable and Non-Renewable EnergyRenewable and non-renewable energy explained for students: fossil fuels, solar, wind, water and nuclear power, why energ🔭Telescopes and Studying SpaceHow telescopes work and how scientists study space, for ages 11-14: refractors and reflectors, light-gathering and magni🧠The Brain and Nervous SystemA middle-school lesson on the nervous system: neurons, the brain's main regions, the spinal cord, reflexes, and how elec♻️The Carbon CycleThe carbon cycle explained for students: how carbon moves between the air, living things, oceans and rocks, the role of 🫀The Circulatory System: Heart and BloodHow the heart and blood work, for middle school: the four heart chambers, arteries, veins and capillaries, what blood ca🍽️The Digestive SystemHow the digestive system works, explained for middle school: mouth, stomach, small and large intestine, enzymes and nutr🌍The Greenhouse EffectUnderstand the greenhouse effect: how greenhouse gases trap heat and keep Earth warm, why human activity is strengthenin🦴The Human SkeletonThe human skeleton explained for students: the 206 bones, what they are made of, the jobs of the skeleton, joints and mu🫁The Respiratory System: How We BreatheHow breathing works, for middle school: the path of air through nose, trachea and lungs, the alveoli, gas exchange, the 🪨The Rock CycleThe rock cycle explained for middle school: how igneous, sedimentary and metamorphic rocks form and change over millions🫀The Systems of the Human BodyExplore the human body systems: circulatory, respiratory, digestive, nervous, skeletal and muscular systems explained fo
📖 Cuentos
🏜️Echoes in the CanyonAn original adventure story for ages 10-13: two siblings lost in a desert canyon learn to listen, work together, and fol🕰️The Clock That Ran BackwardsAn original mystery for ages 11-13: a strange clock in a repair shop runs backwards, and Mira's investigation reveals a 🕰️The Clockmaker's SecretAn original middle-grade short story for ages 10-13: an apprentice inherits her grandfather's mysterious clock shop and 🐦The Clockwork BirdAn original story for ages 10-13: a young inventor mends a broken clockwork bird and learns that real songs come from th📓The Code in the Old DiaryAn original mystery for ages 11-13: an old diary full of strange symbols leads Priya to crack a secret code and solve a 🌱The Garden on the Space StationAn original sci-fi story for ages 11-13: when a space station's garden starts dying, young Leo solves the mystery and le⭐The Girl Who Mapped the StarsAn original story for ages 10-13: a curious girl in a lighthouse town charts the night sky, faces doubters, and helps lo⚙️The Inventor's ApprenticeAn original story for ages 10-13: a stubborn apprentice wants to build something brilliant on her first day, but learns 🎶The Island of Forgotten SongsAn original story for ages 10-13: a quiet girl sails to a vanishing island where every tune the world has forgotten is k📚The Last Library on MarsAn original sci-fi story for ages 11-13: on a struggling Mars colony, a girl fights to save a forgotten library and disc🌌The Legend of the Northern LightsA retelling of the legends of the Northern Lights from Arctic and Nordic peoples, for ages 10-13, with a thoughtful mora🏛️The Museum of Impossible ThingsAn original sci-fi mystery for ages 11-13: a museum's impossible exhibits hide a secret, and Jonah's curiosity uncovers 📚The Mystery of the Old LibraryAn original mystery story for ages 10-13: Maya and Theo follow hidden clues through a dusty old library to uncover a kin🏞️The River That Ran UphillAn original story for ages 10-13: when a village's river mysteriously flows backward up the mountain, a curious boy foll📡The Signal from Station NineAn original sci-fi mystery for ages 11-13: aboard an abandoned space station, young engineer Reza chases a repeating sig🐴The Trojan HorseA retelling of the legend of the Trojan Horse and the fall of Troy for ages 10-13, with a moral about cleverness and a c🏞️The Vanishing LakeAn original mystery for ages 11-13: when their town's lake disappears overnight, two friends follow the clues undergroun
📚 Libros
✈️A Short History of FlightA free online non-fiction book for ages 9-12: the story of flight from early dreamers and hot air balloons to the Wright⚕️A Short History of MedicineA free non-fiction mini-book for ages 11-14: the story of medicine from ancient healers to germs, vaccines, antibiotics 🚀A Short History of Space ExplorationA free non-fiction mini-book for kids: from the first rockets and Sputnik to the Moon landings, Mars rovers and the sear💡Great Inventions That Changed the WorldA free non-fiction mini-book for kids: discover the wheel, printing press, electricity, the telephone, flight and other 🌉How Bridges and Buildings Stand UpA free non-fiction mini-book on structural engineering for kids: forces, arches, beams, trusses, suspension bridges, fou🧠How Your Brain WorksA free non-fiction mini-book for ages 11-14: discover neurons, memory, emotions, the senses and sleep, and learn how you🏰Life in Medieval TimesA non-fiction history book for ages 10-13 about the Middle Ages: the feudal system, castles and knights, peasants and to🧭The Age of ExplorationA non-fiction history book for ages 10-13 on the Age of Exploration: why Europeans sailed the oceans, Columbus and da Ga🔺The Ancient EgyptiansA non-fiction book for ages 10-13 on ancient Egypt: the River Nile, pharaohs and pyramids, gods and mummies, hieroglyphs🏛️The Ancient GreeksA non-fiction history book for ages 10-13 on ancient Greece: city-states, democracy in Athens, the warriors of Sparta, g🏟️The Ancient RomansA non-fiction history book for ages 10-13 on ancient Rome: from a city to a mighty empire, the army and roads, emperors,🫀The Human Body: An Owner's GuideA free non-fiction mini-book for kids: explore the skeleton, muscles, heart, lungs, brain and digestion, and learn how y🏭The Industrial RevolutionA non-fiction history book for ages 10-13 on the Industrial Revolution: the steam engine, factories and machines, railwa🌲The Secret Life of TreesA free non-fiction book for ages 9-13: how trees grow, make food from sunlight, defend themselves, talk through undergro💻The Story of ComputersA free non-fiction mini-book on the history of computers: from the abacus and Babbage's engines to room-sized machines, ⚡The Story of ElectricityA free online non-fiction book for ages 11-14: discover what electricity is, how circuits and currents work, the scienti🔤The Story of Writing and the AlphabetA non-fiction book for ages 10-13 on the history of writing: from cave marks and cuneiform to hieroglyphs, the first alp🦠The Tiny World of MicrobesA free online non-fiction book for ages 11-14: explore the invisible world of bacteria, viruses, fungi and other microbe🏛️The Wonders of the Ancient WorldA free online non-fiction history book for ages 9-13: discover the Seven Wonders of the Ancient World, from the Great Py🌟Women Who Changed the WorldA free non-fiction mini-book about remarkable women in history: Marie Curie, Ada Lovelace, Rosa Parks, Wangari Maathai,
⚽ Deporte
💪Bodyweight Strength ExercisesLearn safe bodyweight strength exercises for young athletes: how muscles get stronger, correct form for squats, push-ups🏃♂️Building Stamina and EnduranceLearn how to build stamina and endurance: what aerobic fitness is, how the body adapts to cardio training, and a safe, b❤️Exercise and a Healthy HeartDiscover how exercise builds a healthy heart: how the heart works, what aerobic activity does to it, why a strong heart 🤸Flexibility and StretchingLearn about flexibility and stretching: what flexibility is, the difference between dynamic and static stretches, when t🫀How the Heart and Lungs Work During ExerciseLearn how your heart and lungs work during exercise: how oxygen reaches your muscles, why your heart beats faster, and h🎯How to Set Fitness GoalsLearn how to set fitness goals that actually work: use the SMART method, balance outcome and process goals, track progre💪How Your Muscles WorkDiscover how your muscles work: how they contract to pull bones, why muscles work in pairs, what makes them stronger, an💧Hydration and ExerciseUnderstand hydration and exercise: why water matters, how sweating cools you, the signs of dehydration, when to use spor🌈Moving to Feel Good and Reduce StressLearn how exercise boosts mood and reduces stress: the brain chemistry behind 'feeling good', how movement calms worry, 🤝Teamwork and SportsmanshipLearn about teamwork and sportsmanship in sport: how to play your role on a team, communicate, win and lose gracefully, 😴Why Sleep Matters for AthletesDiscover why sleep matters for athletes: how sleep repairs muscles, builds skills, releases growth hormone, sharpens rea
🤖 IA
♿AI and Accessibility: Helping EveryoneHow AI improves accessibility: screen readers, live captions, image descriptions, speech tools and navigation help for p🚀AI and the Jobs of the FutureA friendly, balanced look for middle-schoolers at AI and future jobs: which work changes, which new jobs appear, and the🎨AI in Art and MusicHow AI makes art and music: learning patterns from examples, generating new pieces, and honest questions about copying, 🌍AI in Everyday LifeA grounded middle-school guide to AI in everyday life: where it really helps, how it works, its real limits and risks, a🌦️AI in Weather ForecastingHow AI helps forecast the weather: a middle-school guide to physics models, machine-learning forecasts like nowcasting, 🔀Classification vs PredictionUnderstand the two main jobs of supervised AI: classification sorts things into categories, regression predicts a number👁️Computer Vision and Face RecognitionHow computer vision and face recognition work: from pixels to features to matching faces, plus real limits, errors, bias🌳Decision Trees ExplainedA clear guide to decision trees in machine learning: how a model learns yes/no questions to sort data, why they are easy🩺How AI Helps DoctorsA middle-school lesson on how AI supports doctors: reading medical scans, sorting records, predicting risk and speeding 🎙️How AI Recognizes SpeechHow AI recognizes speech, step by step: from sound waves to digital numbers, to phonemes and words, plus why it mishears🎯How Recommendation Systems WorkA middle-school guide to recommendation systems: how YouTube, Netflix and Spotify suggest content using collaborative fi🔎How Search Engines WorkA clear middle-school lesson on how search engines work: crawling, indexing, ranking with signals, and how AI shapes res📧How Spam Filters WorkHow email spam filters work: a middle-school guide to the rules, machine learning and probability that sort junk mail fr🌍How Translation Apps WorkHow translation apps work: from old word-by-word systems to neural machine translation that learns from millions of exam🤝Making AI Fair for EveryoneA clear middle-school lesson on making AI fair: why AI can be unfair, how biased data causes it, real examples, and what🧠Neural Networks ExplainedA middle-school guide to neural networks: neurons, weights, layers, activation, and how training with backpropagation le🏷️Supervised vs Unsupervised LearningA clear guide to supervised vs unsupervised learning: how labelled examples train a model to predict, how unlabelled dat🎯Training, Testing and AccuracyLearn how AI is built: how a model trains on examples, why it must be tested on data it never saw, and what accuracy rea⚙️What Is Machine Learning?A middle-school guide to machine learning: training data, features, models, neural networks, supervised vs unsupervised
💻 Programación
📡Broadcasting Messages in ScratchA step-by-step middle-school lesson on broadcasts in Scratch: how 'broadcast' and 'when I receive' let sprites talk to e🧮Building a Calculator in PythonBuild a working calculator in Python step by step: read numbers with input, do the four operations, handle the divide-by👯Cloning Sprites in ScratchA step-by-step middle-school lesson on clones in Scratch: how 'create clone', 'when I start as a clone', and 'delete thi🧩Creating Custom Blocks in ScratchA middle-school Scratch coding lesson on custom blocks: learn to make your own blocks with My Blocks, add inputs, avoid 🎨CSS Colours and FontsA friendly middle-school lesson on CSS colours and fonts: set text and background colours with names, hex and rgb, choos🧩Functions: Reusable Blocks of CodeA middle-school coding lesson on functions: learn how to define and call functions, pass arguments, return values, and w↩️Functions That Return ValuesUnderstand how Python functions return values: the difference between return and print, capturing results in variables, 🔢How Computers Store Data (Binary)Discover how computers store everything as binary: bits and bytes, why machines use only 0s and 1s, how numbers, letters🧠How the CPU WorksMeet the CPU, the brain of the computer: learn the fetch-decode-execute cycle, what registers and the clock do, how bill🌐How the Internet WorksHow the internet works explained simply: IP addresses, packets, servers and clients, DNS, and what happens when you open📝HTML Forms and InputsA clear, hands-on lesson on HTML forms and inputs for middle-school coders: build a form with text boxes, email fields, 🏷️Introduction to HTML TagsA beginner-friendly introduction to HTML tags: headings, paragraphs, links, images, lists and the page skeleton. Learn h📋Lists and ArraysLearn what lists and arrays are: how computers store many values in one place, how to add, read, and change items by the🔁Loops: Making the Computer RepeatA middle-school coding lesson on loops: learn what loops are, how for and while loops work, why they save time, and see 🎮Making a Platformer in ScratchA step-by-step middle-school lesson on building a platformer in Scratch: left and right movement, gravity, jumping with 🔳Nested Loops and PatternsA middle-school coding lesson on nested loops: learn how a loop inside a loop works, why the inner loop runs fully for e⚖️Python Comparison and LogicLearn Python comparison and logic: ==, !=, <, >, the True and False booleans, and the and, or, not operators. Build cond🔁Python For LoopsLearn Python for loops: loop over lists and strings, use range() to count, build running totals with an accumulator, and🔀Python: if, elif, elseMaster Python decisions with if, elif and else: comparison operators, branching, why elif beats stacked ifs, chained con⌨️Python Input and OutputLearn Python input and output: print() with sep and end, reading text with input(), converting strings to numbers with i📋Python Lists in DepthGo deeper with Python lists: indexing, slicing, append, insert, remove, sort and reverse, len, and looping with for. Mas🔁Python Loops and ListsCombine Python loops and lists: use a for loop to visit every item, build lists, count and total values, and use range()🔢Python Numbers and MathLearn Python numbers and math: integers, floats, the arithmetic operators, floor division, modulo, exponents, operator o🔁Python While LoopsMaster Python while loops: how a condition controls repetition, updating the loop variable, avoiding infinite loops, bre🎲Random Numbers and Games in PythonMake Python games unpredictable with the random module: use randint, choice, shuffle and random to roll dice, pick cards✍️Working with Text and StringsLearn how to work with text and strings in Python: create strings, join them, slice them, change case, find and replace,🧹Writing Clean Code and CommentsLearn to write clean Python code: clear variable names, helpful comments and docstrings, avoiding repetition with functi