What is Science?

Science isn’t a pile of facts to memorise. It’s a method — a careful, repeatable way of asking questions about the world and letting reality, not opinion, decide the answers.

Observation comes first

Everything starts with noticing something. Ice melts in your hand. The sky turns red at sunset. A plant leans toward the window. An observation is just a careful record of what actually happens — measured where possible, described plainly, and something anyone else could notice too.

A hypothesis is a testable guess

Once you’ve noticed something, you propose an explanation. A hypothesis is a proposed answer stated so clearly that it could turn out to be wrong. That last part is the whole point.

“Plants grow toward light because light gives them energy” is a hypothesis: you can block the light and see what happens. “My plant likes me” is not — there’s no observation that could ever settle it.

Theory means something stronger than “guess”

In everyday speech a “theory” is a hunch. In science it’s almost the opposite: a theory is an explanation that has survived years of testing and ties together huge amounts of evidence — like the theory of evolution or the germ theory of disease. Theories are the sturdiest ideas we have, not the flimsiest.

The loop, not the ladder

The scientific method is often drawn as a straight staircase, but in practice it’s a loop you go around again and again:

1. Observe something.
2. Ask a question about it.
3. Hypothesise a testable answer.
4. Predict what you’d see if the hypothesis were true.
5. Test with an experiment or new observations.
6. Revise — and go around again.

Each trip round the loop makes the idea a little more trustworthy, or replaces it with a better one.

Your turn: is it testable?

The heart of science is telling testable claims from untestable ones. For each statement below, decide whether it’s a testable hypothesis — something an experiment or observation could support or knock down.

Key words to keep

With the method in hand, we can point it at the most basic question of all: what is everything made of? That’s where we head next — to atoms.