Fanlab

Science isn’t in the book — it’s in life

From grade 1 to university: every topic in a real-life situation. 3D experiments, animated explanations, missions, quizzes and a leaderboard — in Uzbek, Russian and English.

Physics — 132 experiments, from grade 7 to university

Mechanics

Motion, force, pressure, energy and equilibrium

• Physical quantities and measurement — Grade 7. How many grams does a melon at the market really weigh, and how accurate is the measurement?
• Metro: from station to station — Grade 7. How does a metro train stop in exactly the right place at the next station?
• Mass and density — Grade 7. Identical cubes: why is a gold cube about 240 times heavier than a cotton one?
• Car braking — Grade 7. Why is it essential to slow down on a wet road?
• Pressure of a solid — Grade 7. Why don't skis sink into snow, while a thin heel punches through it?
• Atmospheric pressure — Grade 7. Why does water boil on Mount Chimgan before reaching 100 °C?
• Newton's laws — Grade 7. Why does the scales read more when a lift starts moving, and zero if the cable snaps?
• Roller coaster — Grade 7. Why doesn't the car fall off at the top of the loop?
• History of physics: al-Biruni, Ulugh Beg — Grade 7. How did al-Biruni measure the density of gold, and Ulugh Beg the latitude of Samarkand?
• Vectors and relative motion — Grade 7. When a boat crosses the Amu Darya, why does it land downstream rather than directly opposite?
• Circular motion: the bicycle — Grade 7. Why does a bicycle speed up when you change gear, though you pedal at the same rate?
• Pascal's law and hydraulics — Grade 7. How does one person lift a 1.5-tonne car at a garage?
• Elasticity and deformation — Grade 9. How much load can a bridge cable carry, and when does it snap?
• Why doesn't a ship sink? — Grade 10. A steel ship floats, but a steel nail sinks — why?
• Simple machines: lever, pulley — Grade 10. Why doesn't a crane tip over, and how does a pulley reduce the force?
• Basketball: the free throw — Grade 10. At what angle must the ball be thrown to drop into the basket?
• Momentum and its conservation — Grade 10. How do seat belts and airbags save us?
• Banked turn — Grade 10. What keeps a car on a bend, and why are roads banked?
• Centre of gravity and equilibrium — Grade 10. How far can books be stacked over the edge of a table, and when does a box tip over?
• Aeroplane wing — Grade 10. Where does lift come from, and why does an aeroplane need a longer run-up at high altitude?
• Dynamics of a rigid body — Grade 10. Why does a skater spin several times faster when she pulls in her arms?
• Non-inertial frames of reference — Grade 10. Why does the plane of a pendulum nobody touches turn over several hours?
• Inclined plane and Atwood machine — Grade 10. Why is it easier to drag a load up a ramp, yet the work does not decrease?
• Free fall and air — Grade 10. A coin and a feather fall differently in air but together in a vacuum — why?
• Jet propulsion and the rocket — Grade 10. What does a rocket push against to fly, and why does it have several stages?
• Viscosity and flow — Grade 10. Why does a ball sink slowly in honey, while water in a pipe suddenly “roars” into turbulence?
• Gyroscope and precession — Year 1. Why doesn't a spinning top fall over, but slowly begins to turn its axis instead?
• Lagrangian mechanics and chaos — Year 2. Why does a double pendulum released identically swing differently within a few seconds?
• Hamiltonian mechanics — Year 2. How can the whole future of a swing fit on a single map?

Oscillations and waves

Pendulum, sound, resonance, interference

• Swing — Grade 10. When is a swing pushed so that it goes higher?
• Spring pendulum — Grade 10. Why does a car without shock absorbers keep bouncing for so long after a bump?
• Waves on a rope and a spring — Grade 10. When you shake a rope, what travels along it — matter or energy?
• Sound: speed, pitch, ultrasound — Grade 10. How can we measure the distance to a cliff from its echo in the mountains?
• The dutar string and sound — Grade 11. Why does the pitch rise when a string is shortened or tightened?
• Waves and the Doppler effect — Grade 11. Why does an ambulance siren sound higher as it approaches?
• Bridge resonance — Grade 11. Why do soldiers break step when crossing a bridge?
• Coupled oscillations — Grade 11. Why do two pendulums joined by a spring swing in turn?
• Nonlinear oscillations — Year 2. How does a child make a swing go without pushing, and how can a pendulum stand upside down?
• Fourier: the spectrum of sound — Year 3. How does a spectrum analyser tell a pipe from a drum at a glance?

Molecular physics and thermodynamics

Heat, gases, engines

• Melting, boiling and evaporation — Grade 7. How long does a kettle take to boil, and why does boiling water not get hotter than 100 °C?
• Calorimeter: heat balance — Grade 7. If we add cold water to hot tea, what will the temperature be, and where does the heat go?
• Tandoor and sandal: heat — Grade 7. Why is a tandoor built of clay, and why is the flatbread baked on its wall?
• Gas under a piston — Grade 9. Why does tyre pressure drop in winter, and why does a pump get hot?
• Humidity and dew — Grade 9. Why does an ice-cold glass “sweat”, and how does an air conditioner dry a room?
• Heat engine: the Otto cycle — Grade 9. What fraction of the petrol's heat turns the wheels, and why not all of it?
• Entropy and the arrow of time — Grade 9. Why don't mixed gases separate by themselves — and what if we ran time backwards?
• Brownian motion and diffusion — Grade 9. Why does a particle under the microscope jitter endlessly, and how does this tell us the size of atoms?
• Surface tension and capillarity — Grade 9. How does a steel needle float on water, and why does water rise by itself in a thin tube?
• Crystalline and amorphous solids — Grade 9. Why is table salt cubic, and why do diamond and graphite differ although both are carbon?
• Phase transitions — Grade 10. Why does water boil at 120 °C, not 100 °C, in a pressure cooker?
• Thermal expansion — Grade 10. Why are gaps left between rails, and why doesn't a lake freeze to the bottom?
• Refrigerator and heat pump — Grade 10. How does heat flow “uphill” from a cold fridge into a warm kitchen?
• Real gases — Grade 10. Why does the pressure in a propane cylinder stay constant until it is empty, and why can CO₂ not be liquefied above 31 °C?
• Maxwell–Boltzmann distribution — Grade 10. How do random collisions give rise to an exact law — the Gaussian curve?
• Transport phenomena — Year 1. Why does the scent of perfume spread slowly through a room, and how does a thermos keep tea hot?
• Quantum statistics — Year 4. Why do the electrons in a metal contribute almost nothing to its heat capacity?
• Phase transition and fluctuations — Year 4. Why does a heated magnet suddenly stop attracting, and what trembles at that point?

Electricity and magnetism

Charge, current, field, induction

• Electrification, Coulomb's law — Grade 7. Why does hair follow a balloon after it has been rubbed on it?
• Electric circuit, Ohm's law — Grade 7. Why does the circuit breaker trip when a kettle and an iron are on together?
• Conductor, dielectric, lightning — Grade 7. In a thunderstorm, why is it safe inside a car but dangerous under a lone tree?
• Power sources, EMF, internal resistance — Grade 7. Why can't a car battery be short-circuited, while a lemon cannot light a lamp?
• Work and power of an electric current — Grade 8. Which appliance “eats” most of the monthly electricity bill?
• Electric motor — Grade 8. What makes a current-carrying wire turn, and why doesn't a motor speed up without limit?
• Aurora and the Lorentz force — Grade 8. Why does the aurora glow only around the poles?
• Electric field and potential — Grade 8. What does the “invisible mountain” around a charge look like: field lines and equipotential surfaces
• Capacitor and capacitance — Grade 8. Why does a camera-flash capacitor take seconds to charge but discharge in an instant?
• Circuits and Kirchhoff's rules — Grade 8. Why are the sockets at home connected in parallel, and how does current split at a junction?
• Electric current in metals — Grade 8. If electrons creep along a wire at less than a millimetre per second, why does the lamp light instantly?
• Electrolysis, Faraday's laws — Grade 8. How can a spoon be plated with copper, and how much current does it need?
• Electric current in vacuum and gases — Grade 8. How does a neon sign light up, and how is the beam drawn in an old television tube?
• Magnetic field — Grade 8. What turns a compass needle — the Earth, a magnet or a current in a wire?
• Electromagnet and relay — Grade 8. How does a crane lift a tonne of iron, and why does it drop it when the current is cut?
• Shake torch — Grade 10. How does a torch light up without a battery?
• Self-induction — Grade 10. Why does a spark appear when a switch is opened — the current in the coil cannot stop at once?
• Magnetic properties of matter — Grade 10. Why does iron stick to a magnet, bismuth shrink away from it, and hot nickel let go?
• Plasma — the fourth state — Grade 10. How does the gas in a lightning channel or a neon lamp turn into conducting plasma?
• Power transmission line — Grade 11. Why is electricity transmitted at hundreds of kilovolts?
• Microwaves and Wi-Fi — Grade 11. How can chocolate in a microwave oven be used to measure the speed of light?
• Radiation from a dipole antenna — Grade 11. How does an oscillating charge produce a wave that travels far away?
• Oscillating circuit (LC) — Grade 11. When you turn the radio dial, how does the circuit pick out a single station?
• Alternating current and RLC — Grade 11. The socket says 220 V, yet the voltage reaches 311 V — how?
• Radio communication and radar — Grade 11. How does sound “ride” on a radio wave, and how does radar see an aeroplane?
• Charged-particle accelerator — Grade 11. How does a cyclotron accelerate a proton, and how does a mass spectrometer separate isotopes?
• Thermoelectric phenomena — Year 2. If we heat the junction of two different wires, why does a current appear?
• Vector fields: div and curl — Year 3. Where does a paddle wheel in a river turn, and where does cyclone wind gather?

Optics

Reflection, refraction and wave properties of light

• Car mirrors and the periscope — Grade 7. Why does a car in the wing mirror look farther away than it really is?
• Laser, water and optical fibre — Grade 7. Why does the internet run as light inside glass fibre?
• The eye and spectacles — Grade 7. Why do “−3” spectacles suit one person but not another?
• Shadow and eclipses — Grade 7. Why can only people in a narrow strip see a solar eclipse as total?
• Measuring the speed of light — Grade 9. How was light, travelling 300 thousand km every second, ever measured?
• Optical instruments — Grade 9. How can a microscope with two lenses magnify a cell 400 times?
• Interference and diffraction — Grade 11. Why do a CD and a soap bubble shimmer in rainbow colours?
• Polarisation of light — Grade 11. Why do polarising glasses “switch off” the glare on water?
• Laser physics and holography — Grade 11. When does a laser “switch on”, and why does it first emit strong spikes?
• Luminous flux and illuminance — Grade 11. If we raise the lamp to twice the height, how many times dimmer is the desk lit?
• Infrared, UV and X-rays — Grade 11. How does a thermal camera “see” a person in the dark, and an X-ray a bone?
• Scattering of light — Year 1. Why is the sky blue and the sunset red?
• Crystal optics — Year 1. Why does writing seen through Iceland spar appear double?
• Interferometers and LIGO — Year 1. How can light detect a shift hundreds of times smaller than the diameter of a proton?
• Resolving power — Year 1. Why does a large telescope separate a double star while a small one sees a single blob?
• Nonlinear optics: the green laser — Year 2. How does infrared light pass through a crystal and come out green?

Atomic and quantum physics

Photon, electron, atomic nucleus

• Semiconductor physics — Grade 9. Why does a solar panel work poorly in the heat, and what does the colour of an LED depend on?
• The photoelectric effect — Grade 11. Why can strong red light not knock out an electron, while weak ultraviolet light can?
• Atomic structure and spectra — Grade 11. Why does a neon sign glow red and a sodium lamp yellow?
• Radioactivity, half-life — Grade 11. How can we tell how old an ancient wooden object is?
• Nuclear reactions — Grade 11. Why doesn't a nuclear power plant reactor explode, and how is it controlled?
• Orbitals of the hydrogen atom — Grade 11. Where is the electron in an atom, and where do the shapes of orbitals come from?
• Thermal radiation and Planck — Grade 11. Why does heated iron glow first red, then yellow, then white?
• Photon momentum and the Compton effect — Grade 11. Can sunlight push a sail, and what happens when a photon hits an electron?
• De Broglie waves — Grade 11. An electron is a particle, so why does it pass through a crystal and draw wave-like rings on the screen?
• Rutherford's experiment — Grade 11. Why do most alpha particles pass straight through gold foil, while some bounce back?
• The atomic nucleus and binding — Grade 11. Why does the Sun gain energy by joining light nuclei, while a nuclear power plant gains it by splitting heavy uranium?
• Thermonuclear fusion — Grade 11. How does the Sun turn hydrogen into helium, and can this be repeated on Earth?
• Detecting particles — Grade 11. How can invisible radiation be seen, counted and guarded against?
• Elementary particles — Grade 11. What is the universe made of, and how is antimatter used in a hospital?
• Spin, the Zeeman effect and MRI — Year 1. Why does a beam of silver atoms split in two in a magnet, and how does MRI see the body?
• Many-electron atoms — Year 1. How is the periodic table built, and how does an X-ray “recognise” a substance?
• Bands in solids — Year 1. Why does copper conduct current but diamond does not: allowed and forbidden bands
• Schrödinger and quantum tunnelling — Year 3. How does an electron pass through a barrier higher than its energy, and how does an STM “see” atoms?
• Quantum dots and the potential well — Year 3. Why do quantum dots made of the same material glow in different colours depending on their size?
• The molecule: bonding and spectra — Year 3. How does a hydrogen molecule form, and why does CO₂ absorb infrared radiation?
• Superconductivity — Year 3. Why does a disc cooled in liquid nitrogen float above a magnet?

Gravitation and the universe

Planets, artificial satellites, relativity

• The Solar System — Grade 7. If the Sun were a ball 1 m across, where would the Earth be?
• Scales of the universe — Grade 9. From quarks to the Universe: which laws of physics rule at each scale?
• Newton's cannon: an artificial satellite — Grade 10. At what speed must an object be launched so that it never falls back to Earth?
• Special relativity — Grade 10. Why does a clock on a GPS satellite run faster than one on Earth?
• Law of universal gravitation — Grade 10. Do two lead spheres attract each other, and how can we “weigh” the Earth?
• Relativistic dynamics — Grade 10. Why can't a proton be accelerated to the speed of light, while its energy grows without limit?
• Kepler's laws — Grade 10. What path does a planet follow around the Sun, and at what speed?
• Physics of stars — Year 1. Where does the Sun stand among the stars, and how will it end?
• The expanding universe — Year 1. Why are galaxies moving away from us, and how old is the Universe?
• Black holes — Year 4. Which rays fall into a black hole, and why is the shadow bigger than the horizon?

Chemistry — 87 experiments, from grade 7 to university

Fundamentals of chemistry

Substances, mixtures, atomic-molecular theory, the mole

• The chemistry lab and safety — Grade 7. Why must a test tube be pointed away from people when heated?
• Pure substances and mixtures — Grade 7. How can pure table salt be separated from cloudy rock salt?
• Physical and chemical changes — Grade 7. Melting ice and rusting a nail: in which one is a new substance formed?
• Chemical formula and valency — Grade 7. Why is water H₂O but aluminium oxide Al₂O₃? How does valency “assemble” a formula?
• Mole, molar mass and volume — Grade 7. 18 g of water and 2 g of hydrogen contain the same number of particles. Why? How much space does a mole of gas take up?
• From alchemy to the periodic law — Year 1. Alchemists thought they had “turned” iron into copper — what had really changed on the scales?

Atomic structure and the periodic law

Electron shells, isotopes, Mendeleev's table

• Atomic structure and isotopes — Grade 7. Why is the relative atomic mass of chlorine not a whole number, but 35.45?
• Elements and the periodic table — Grade 7. Why do 118 elements fit into one table, and what does it tell us about the atom?
• Electron shells and orbitals — Grade 8. Why do sodium salts turn a flame yellow and copper salts blue-green?

Chemical bonding

Covalent, ionic and metallic bonding, molecular shape, crystals

• Types of chemical bonding — Grade 8. Why is table salt a hard crystal, water a liquid and copper wire a conductor of current?
• The molecule: orbitals and symmetry — Year 1. Why does liquid oxygen hang between the poles of a magnet while liquid nitrogen runs off?

Chemical reactions

Types, heat of reaction, rate and equilibrium

• Reaction equations — Grade 7. If iron burns in a closed flask, what do the scales show? Where do the atoms go?
• Combustion, flames and oxides — Grade 7. Why does a candle go out under a glass, and which part of a flame is hottest?
• Rate of reaction and catalyst — Grade 8. Why does chalk powder “fizz” faster than a lump, and why does food spoil slowly in a fridge?
• Reversible reactions and equilibrium — Grade 8. Why does an NO₂ ampoule go pale in ice, and why does an ammonia column work at high pressure?
• Chemical industry and plants — Grade 9. Polyethylene from Kashkadarya gas, fertiliser from air: how does a reaction become a plant?

Solutions and electrolytes

Concentration, dissociation, pH, hydrolysis

• Acids and metals — Grade 7. Which metal displaces hydrogen from an acid, and why does copper stay silent?
• Acids, bases and indicators — Grade 7. Why does red cabbage juice turn red in lemon and blue in soda?
• Water purification and softening — Grade 7. How does cloudy canal water come out clean from a tap, and why does scale form in a kettle?
• Electrolytic dissociation — Grade 9. Why does a lamp glow brightly in salt water, not at all in sugar water, and dimly in vinegar?
• Hydrolysis of salts and the medium — Grade 9. Why is a soda solution alkaline, ammonium chloride acidic and table salt neutral?
• Solutions and solubility — Grade 11. Why does more sugar dissolve in hot tea, while fizzy water quickly goes flat when warm?
• Concentration of a solution — Grade 11. Saline is 0.9 % — how many mol/L is that? How is it prepared in a pharmacy?
• Raoult's law, distillation and osmosis — Year 1. Why is salt spread on roads in winter and antifreeze put in a radiator?

Redox reactions and electrochemistry

Electron balance, galvanic cell, corrosion

• Redox reactions — Grade 8. Why does permanganate go colourless in acid but turn green in alkali?
• Electrolysis and corrosion — Grade 9. Current turns table salt into chlorine and alkali — so why does an iron pipe rust?
• Galvanic cells and corrosion — Year 1. What voltage does a battery give, and what protects an underground pipe from rust?

Chemistry of the elements

Non-metals, metals and their compounds

• Air: composition and pollution — Grade 7. What is in the air over Tashkent, why does fog thicken in winter, and why is rain acidic?
• Oxygen and ozone — Grade 7. Why does a glowing splint burst into flame in oxygen, and what does the ozone layer protect us from?
• Hydrogen — the lightest gas — Grade 7. How many times lighter than air is hydrogen, and why is it tested with a “pop” before being lit?
• Water: composition and properties — Grade 7. When we split water with a current, why do we get twice as much hydrogen as oxygen?
• Mineral resources — Grade 7. From which ore, and how, are Muruntau gold and Almalyk copper extracted?
• Lime and classes of compounds — Grade 8. How do quicklime and slaked lime on a wall turn back into limestone?
• Non-metals and halogens — Grade 8. Why does chlorine displace bromine, and why does iodine turn violet in petrol?
• Chlorine and hydrochloric acid — Grade 8. What disinfects swimming-pool water, and why does hydrogen chloride shoot up as a “fountain”?
• The oxygen group and sulfur — Grade 8. How is yellow sulfur obtained from natural gas in Muborak, and why is H₂S dangerous?
• Sulfuric acid and the contact process — Grade 8. How does the gas from copper smelting in Almalyk become sulfuric acid?
• Nitrogen, ammonia and nitric acid — Grade 8. How does nitrogen from the air become ammonia, saltpetre and fertiliser for cotton?
• Phosphorus and mineral fertilisers — Grade 8. What do the numbers “16-16-16” on a fertiliser bag mean, and how can a fertiliser be identified?
• Carbon and its compounds — Grade 9. Diamond and graphite are both carbon — so why is carbon monoxide so dangerous?
• Silicon and silicates — Grade 9. How are window glass, cement and solar panels made from sand?
• Making cast iron and steel — Grade 9. How is iron obtained from brown ore, and how does cast iron become steel?
• Metals and alloys — Grade 9. Why does an iron nail turn red in copper sulfate, and why is bronze harder than copper?
• Alkali metals and soda — Grade 9. Why is sodium stored in paraffin oil, and why is soda made from table salt and limestone?
• Aluminium and its compounds — Grade 9. Why does light aluminium not rust, yet dissolve in both acid and alkali?
• Copper, silver, gold and zinc — Grade 9. Why is copper sulfate blue, why is silver the best conductor, and how is gold melted?
• Chromium and manganese: coloured ions — Grade 9. Why can chromium compounds be yellow, orange, green and blue?
• Iron and its compounds — Grade 9. How do we tell Fe²⁺ from Fe³⁺, and what does the iron in our blood do?
• Patterns in s- and p-block elements — Year 1. Why does caesium explode in water, lithium fizz gently, and fluorine act as the strongest oxidising agent?
• d- and f-block elements: colour, redox — Year 1. Why does a single element, vanadium, show four colours, and why are Zr and Hf almost twins?
• Complex compounds and ligands — Year 1. Why does copper sulfate turn deep blue when ammonia is added, and how did Werner explain it?
• Chemical plant: reactors and workshops — Year 4. How much current does a tonne of chlorine need, and how is 99.7 % of SO₂ turned into SO₃?

Organic chemistry

Hydrocarbons, alcohols, acids, proteins, polymers

• Chemistry in our body — Grade 7. Which elements is our body made of, and how much energy does a plate of plov provide?
• Organic chemistry: structure — Grade 10. Why does burnt sugar leave charcoal, and why does carbon form four bonds?
• Isomers and nomenclature — Grade 10. Butane and isobutane in a lighter have the same formula — so why are they different substances?
• Alkanes and cycloalkanes — Grade 10. Methane in a gas hob and propane in a cylinder belong to one family — so why is one a gas and the other a liquid?
• Alkenes and alkadienes — Grade 10. Why does ethene decolourise bromine water and ripen tomatoes?
• Polymers, rubber and fibres — Grade 10. How are a polyethylene bag, a tyre and a cotton fibre built, and where do they end up?
• Alkynes, benzene and styrene — Grade 10. What gas comes from calcium carbide and water, and why does it give a flame that melts metal?
• Natural gas, oil and coal — Grade 10. How are petrol, kerosene and fuel oil obtained from the same black crude oil?
• Alcohols and ethers — Grade 10. Why do ethanol and dimethyl ether have the same formula but boiling points differing by over 100 °C?
• Phenol, aldehydes and ketones — Grade 10. Which reaction turns a test tube into a mirror, and why can't acetone do it?
• Acids, esters and soap — Grade 10. How does vinegar plus alcohol give the smell of banana, and cottonseed oil give soap?
• Carbohydrates: glucose and starch — Grade 10. Why does bread turn blue when iodine is dropped on it, while cotton doesn't?
• Identifying organic substances — Grade 10. Six unlabelled test tubes: which reagent “gives away” which organic substance?
• Stereochemistry and conformations — Year 2. Two “mirror” molecules with the same formula: why does one heal and the other harm?
• Radical and electrophilic mechanisms — Year 3. Why does ethene add bromine at once, while methane reacts with chlorine only in light?
• SN1, SN2 and elimination — Year 3. Replace a single bromine: why do we sometimes get inversion, sometimes a racemate, sometimes an alkene?
• The aromatic ring and azo dyes — Year 3. How do the bright colours of Margilan atlas silk arise from the benzene ring?
• Carbonyl compounds and synthesis — Year 3. How are the smells of banana, cinnamon and vanilla synthesised in a flask?
• Heterocycles and DNA — Year 3. Why is pyridine a base while pyrrole hardly is — and what holds the DNA double helix together?
• Amino acids and proteins — Year 3. Why does casein curdle when acid is added to milk, turning it into yoghurt?
• Physics of macromolecules — Year 3. How is the chain in a cotton fibre coiled, and why is a polymer solution thick?
• Polymer synthesis and kinetics — Year 3. Why does adding more initiator make the polymer form faster, yet with shorter chains?
• Chemistry of polymer materials — Year 3. Why does a PVC pipe turn yellow in the sun, and how does sulfur turn tyre rubber into a real elastic material?

Analytical and physical chemistry

Titration, spectroscopy, thermodynamics, kinetics, colloids

• Thermochemistry and Gibbs energy — Year 1. Why does a cold pack get icy cold, and why does a lime kiln run at 900 °C?
• Electrochemical analysis — Year 1. How do we use an electric current to measure salt, fluoride and lead in water?
• Qualitative analysis and gravimetry — Year 2. Which ions are in an ore or mineral water, and how many milligrams of sulfate?
• Titrimetric analysis — Year 2. How can we tell, to the drop, how much soda is in technical caustic soda?
• Optical methods of analysis — Year 2. How do we measure iron and copper in river water from light absorption?
• Extraction and chromatography — Year 2. How is oil extracted from cottonseed, and how does a mixture separate into spots?
• Spectra: determining structure — Year 2. What is an unknown white powder? UV, IR, NMR and mass spectra can tell
• Alloys: phase diagrams — Year 2. Why does solder melt at a lower temperature than either tin or lead?
• Chemical kinetics and Arrhenius — Year 2. When does a medicine become unusable, and how can a test at 40 °C tell us?
• Catalysis and enzymes — Year 2. Potato, platinum or iron — which decomposes H₂O₂ fastest, and why?
• Colloids and adsorption — Year 2. Why do fine particles stick together and settle when aluminium sulfate is added to cloudy water?
• Computational chemistry and docking — Year 2. How is a new drug “tried out” on a computer before it is synthesised in a flask?

Mathematics — 23 experiments, from grade 5 to grade 9

Numbers and calculation

Natural numbers, fractions, percentages, powers, methods of calculation

• Fractions: from pizza to formula — Grade 5. Is 3/8 of a pizza more or less than 5/8? How do you add them?
• Prime numbers, HCF and LCM — Grade 7. Two buses leave at 12 and 18 minutes — when will they leave together again? What size of tile?
• The number line: from −7 to √2 — Grade 7. −7 °C at night, +4 °C by day — what is the difference? Why can’t √2 be written exactly?
• Powers: from folding to a formula — Grade 7. How thick is a sheet of paper folded 10 times? How many bacteria will there be by morning?
• Roots: from squares to powers — Grade 8. What is the side of a square room with an area of 50 m²? Squares on a grid will not give it

Expressions, equations and inequalities

Expressions with letters, equations, inequalities, systems

• Expressions: from numbers to letters — Grade 7. A taxi: 5 000 soum plus 2 000 soum per km. What is the fare for x km? How are brackets expanded?
• Monomials and polynomials — Grade 7. The vegetable plot was extended by 5 m: which pieces make up the area (x + 3)(x + 5)?
• Special products (algebraic identities) — Grade 7. A carpet has been widened by b on every side — what are the pieces of (a + b)²? Work out 55² in your head
• Algebraic fractions — Grade 7. One pipe fills a pool in 4 hours, another in 12 hours. How long if both are open?
• The linear equation: the balance — Grade 7. The pans are equal: 3 sacks + 4 kg = 2 sacks + 13 kg. How many kilograms is one sack?
• Systems of equations — Grade 7. 2 kg of apples and 3 kg of pears — 29 000; 1 kg and 1 kg — 12 000 soum. The prices?
• Inequalities: ray and interval — Grade 8. A lift carries 630 kg. How many 75 kg people can get in?
• The quadratic equation: the parabola — Grade 8. A vegetable plot has an area of 40 m² and a perimeter of 26 m. What are its sides?

Functions and graphs

Graphs, linear and quadratic functions, exponential and logarithmic functions, trigonometry

• The linear function — Grade 7. Taxi fare: a starting charge + a rate per km. Why is its graph a straight line?

Plane geometry

Triangles, circles, area, similarity, coordinates, vectors

• Point, segment, angle — Grade 7. When two streets cross, why are opposite angles always equal?
• Congruent triangles — Grade 7. Why is a bridge truss made of triangles? How much information fixes a triangle?
• Parallel lines — Grade 7. The street crossing the rails makes eight angles — why are four of them equal?
• Angles of a triangle — Grade 7. If you tear off the three angles and put them side by side, why do you always get a straight angle?
• Compass and straightedge — Grade 7. With an unmarked straightedge and a compass, how do you halve an angle or bisect a segment?
• Pythagoras’ theorem — Grade 8. How high up the wall does the ladder reach? Does the rod fit in the box?

Combinatorics, probability and statistics

Sets, counting, probability, data and charts

• Combinatorics: counting rules — Grade 7. 3 shirts and 2 pairs of trousers — how many different outfits? In how many orders can 6 people stand in a line?
• Statistics: mean, median, σ — Grade 8. What is the “typical” height of a class? By how much does one very tall student shift the average?
• Probability: coin, die, Venn — Grade 9. If we toss a coin 1000 times, how many heads will we get? What is the probability that two dice differ by 1?