Science Puzzle
What Comes Next in the Method?
You notice that a loaf of bread left near a sunny window grows mould faster than an identical loaf in a dark cupboard. You have made an observation, and you have asked a question: is the light causing it?
What is the correct next step, before you run any experiment?
The Answer
Form a hypothesis. A hypothesis is not a guess about what is true; it is a specific, testable statement that makes a prediction which could fail.
Without one, an experiment has nothing to aim at. If you simply "see what happens", any result can be explained after the fact, which means the experiment cannot be wrong, which means it cannot be informative either. A useful hypothesis here might be: "bread exposed to more light will grow mould faster than identical bread kept dark, when temperature and humidity are held equal."
Notice what that phrasing gives you for free. It names the variable you will change, it names what you will measure, it names what must be held constant, and it tells you in advance which result would prove you wrong. Only once that exists can an experiment be designed that is capable of settling anything.
Looking up the answer first is not wrong as background reading, but it is not the next step in the method, and doing it to decide "what result to expect" invites you to see that result whether or not it is there.
The principle: Hypothesis formation. A hypothesis is a specific, falsifiable prediction. It must exist before the experiment, because it is what the experiment is built to test.