How a Flask Keeps Tea Hot by Blocking Heat Three Ways
Learn conduction through solids, convection currents that drive land and sea breezes, radiation that needs no medium, and how a thermos flask defeats all three at once.
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Free study notes for CBSE & ICSE, Classes 6–12.
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Why Railway Tracks Are Laid With Gaps Between Them
Learn the difference between heat and temperature, convert between Celsius and Kelvin, compare laboratory and clinical thermometers, list the effects of heat, and explain expansion in tracks, wires and bimetallic strips.
Read articleWhite Light Is Seven Colours Travelling Together
Learn how a prism disperses white light into VIBGYOR, how a spinning disc and a second prism recombine it, the primary and secondary colours of light, and why a red object looks black in green light.
Read articleWhy AMBULANCE Is Painted Backwards on the Van
Learn the difference between regular and diffused reflection, state and apply the two laws of reflection, list the characteristics of a plane-mirror image, and understand lateral inversion in a periscope.
Read articleWhere the Energy Goes When a Ball Falls to the Ground
Learn when work is done and why it is measured in joules, name the forms of energy with examples, follow the conversion of potential energy into kinetic energy, and trace energy changes in everyday devices.
Read articleYou Are Moving and Sitting Still at the Same Time
Learn why rest and motion depend on the observer, classify translational, rotational, circular and oscillatory motion, convert km/h to m/s, and calculate average speed.
Read articleWhy a Heavy Iron Ship Floats but a Small Nail Sinks
Learn to calculate density and convert its units, measure the density of solids and liquids in the lab, find relative density and explain why it has no unit, and predict floating and sinking.
Read articleHow to Measure the Volume of a Stone With No Shape at All
Learn to convert area and volume units, calculate the area of squares, triangles and circles, find the area of a leaf on graph paper, and measure an irregular solid by water displacement.
Read articleA Weighing Balance Can Solve Any Equation for You
Learn to turn puzzles and patterns into equations, solve them with the balance model and inverse operations, handle brackets and unknowns on both sides, and check every answer by substitution.
Read articleThe Colouring Trick That Proves a Floor Cannot Be Tiled
Learn to decide whether a grid can be covered by domino tiles using parity and colouring, find which shapes tile the plane, and see why rearranging tangram pieces never changes the area.
Read articleHow to Split an Angle Exactly in Half Without a Protractor
Learn to construct perpendicular bisectors, bisect any angle, build angles of 90, 60, 45, 30 and 15 degrees, draw parallel lines by copying angles, and make hexagons and stars from arcs.
Read articleThe Graph You Pick Decides What People Notice
Learn to draw a dot plot and spot clusters and gaps, build and read double bar graphs, describe a trend from a line graph, and pick the right graph for the question being asked.
Read articleOne Unusual Value Can Ruin an Average
Learn to tell a statistical question from an ordinary one, organise data into a frequency table, calculate the mean and the median, and choose the value that represents the data honestly.
Read articleWhy 0.2 Times 0.3 Is Not 0.6
Learn how the decimal point shifts when multiplying and dividing by 10, 100 and 1000, how to place the point in any decimal product, how to divide by a decimal, and how to turn fractions into decimals.
Read articleThe Biggest Square Tile That Fits a Floor With No Cutting
Learn prime factorisation by factor tree and division, find the HCF and LCM from the factors, decide which one a word problem needs, and use the HCF times LCM relationship.
Read articleThe Number Pattern That Explains Why Two Negatives Make a Positive
Learn the sign rules for multiplying and dividing integers, see the number pattern that explains them, apply the order of operations, and use the distributive property to calculate faster.
Read articleWhy Taking Away a Negative Number Makes the Answer Bigger
Learn to compare integers on a number line, add and subtract them with the token model, use additive inverses to turn subtraction into addition, and solve gain-and-loss problems.
Read articleThree Measurements Are Enough to Prove Two Triangles Match
Learn what congruence means, how to write a congruence statement correctly, when SSS, SAS, ASA and RHS apply, and how congruent halves prove the base angles of an isosceles triangle are equal.
Read articleDividing by a Half Makes Things Bigger
Learn what a reciprocal is, why dividing by a fraction means multiplying by its reciprocal, how to divide whole numbers and mixed numbers, and how to check the size of your answer.
Read articleWhy Multiplying Can Make a Number Smaller
Learn to multiply fractions by whole numbers and by each other, picture a fraction of a fraction, cancel before multiplying, and predict whether the answer grows or shrinks.
Read articleThe Angle Outside the Triangle Tells You What's Inside
Learn to use the angle sum and the exterior angle rule, construct triangles from SAS and ASA, and draw an altitude even when it falls outside the triangle.
Read articleNot Every Three Lengths Can Make a Triangle
Learn to name and classify triangles, test three lengths in seconds before drawing, construct a triangle from its sides, and see why the three lengths fix it completely.
Read articleHow to Win a Number Game Before It Starts
Learn to solve arrangement puzzles from clues, use odd and even to prove something is impossible, fill number grids that always work, and find a winning strategy.
Read articleThe F, Z and C Shapes Hiding in Every Parallel Line Diagram
Learn to spot corresponding, alternate and co-interior angles instantly, justify every step of an angle chase, and draw a parallel line with ruler and set-square.
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