Science: ask why, test it, discover

Science is not a list of facts to memorise. It is a method for finding out what is true — and the most exciting part is that it is unfinished. Some of the questions below may be answered by someone reading this page.

01The scientific method

Every experiment in your practical book follows this loop. So does every Nobel Prize.

Try this todayHome experiment: Does salt water boil faster than plain water? Hypothesis first (write it). Two pans, same amount of water, one with 2 spoons of salt, same flame, a timer. Record, compare, explain. (Spoiler: salt raises the boiling point — but the effect on time is small. Measure it!)

Advanced: why "prove" is the wrong wordScience never proves; it fails to disprove. Newton's gravity worked for 200 years until Mercury's orbit and Einstein showed it was an approximation. A good theory is one that makes risky predictions that could be wrong and are not. This humility is science's strength, not its weakness.

02Physics: the rules of everything

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Gravity & motion

Newton's three laws explain a cricket ball and a satellite with the same equations. F = ma is the most useful sentence ever written.

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Energy

Cannot be created or destroyed, only changed — chemical (food) → kinetic (running) → heat. Every machine, every cell, obeys this.

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Light & waves

Light is a wave and a particle. Colours are wavelengths; a rainbow is sunlight sorted by wavelength through raindrops.

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Electricity & magnetism

One force, two faces. A moving magnet makes current (generators); current makes a magnet (motors). Your phone is applied electromagnetism.

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Relativity

Time runs slower for things moving fast or sitting in strong gravity. GPS satellites must correct for this daily — relativity is in your maps app.

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Quantum physics

At the scale of atoms, particles are probabilities until measured. Strange — and the reason LEDs, lasers, MRI and computer chips exist.

Frogs levitating in a magnetic fieldDiamagnetism — a real experiment Cooking with the sun"The Sun's rays do not burn until brought to a focus" — A. G. Bell What is antimatter?Dark matter (CERN)The Higgs boson (CERN)The Large Hadron Collider Wormholes explained Physical quantities and units

03Chemistry: what things are made of

Everything is atoms — ~118 kinds — joined by sharing or swapping electrons. Chemistry is the study of those joins.
A balanced equation is just counting: atoms in = atoms out. Mass is never lost in a reaction.
The periodic table is not a poster to memorise; it is a map. Columns share behaviour because they share outer electrons.
Acids give H⁺, bases accept it; pH measures how much. Your stomach is pH 2; blood is 7.4 and your body fights to keep it there.
Organic chemistry = carbon chemistry = life chemistry. Sugar, DNA, plastic and petrol are all carbon skeletons.

States of matter tutorial Atomic structure resources (AACT)Balanced chemical equations A future in chemistry (Royal Society of Chemistry)Top 10 chemistry jobs

04Biology: the science of life

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DNA

A 2-metre molecule folded into every cell, carrying ~20,000 genes — the recipe book for every protein in you. 99.9% identical between any two humans.

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Mitochondria

The cell's power plants — they turn food and oxygen into ATP, the energy currency. You have about 10 million billion of them.

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Photosynthesis

Sunlight + water + CO₂ → sugar + oxygen. Every breath you take was made by a plant or an ocean alga.

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Evolution

Small inherited changes, selected over millions of years. It explains antibiotic resistance, dog breeds and why your wisdom teeth do not fit.

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The brain

86 billion neurons, each with thousands of connections — more links than stars in the galaxy. Reading this sentence rewired some of them.

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Careers

Medicine, pharmacy, biotechnology, genetics, wildlife, marine biology, agriculture, sports science, teaching, research.

What is DNA? (yourgenome)Mitochondria and metabolism (iBiology)The brain under anaesthesia (iBiology)Cells — Biology4Kids What can you do with a biology degree?Biology careers A–Z

05Cosmology: the biggest questions

The universe is 13.8 billion years old, expanding, and 95% of it (dark matter and dark energy) is something we have not identified. There has never been a better time to become an astronomer.

Is time travel possible? Forward — yes, and proven (fast-moving clocks run slow). Backward — no known way, and physics may forbid it.
What happened before the Big Bang? Possibly the question has no meaning — time itself may have begun with it.
Are we alone? There are more planets than stars. No evidence of life yet; the search (SETI, JWST, Mars rovers) is active.
What is inside a black hole? Our equations break there. Someone will fix them.
Is there an edge to the universe? No edge has been found; the observable part is 93 billion light-years across.

What is cosmology? (Space.com)Astrophysics explained Cosmology news — Sky & Telescope Types of telescope Through the Wormhole (Morgan Freeman) — series Careers in astronomy

06Philosophy and world religions

Science asks *how*; philosophy and religion ask *why* and *how should we live*. A star student can hold both with respect.

The original site offered doors into Hindu, Christian, Islamic and other theologies and into philosophy. We keep the best of those doors here, for the curious mind that wants to understand its neighbours as well as its textbooks.

Nine beliefs of Hinduism What is Christian theology?Islamic thought (Britannica)Philosophy basics Monotheistic religions overview What can you do with a philosophy degree?