Science: Core Concepts and Scientific Method: 17 MCQs with answers

It builds testable explanations checked against evidence.

Science is defined by its process — building explanations that can be checked by observation, measurement and experiment — not by its subject matter or its use of maths.

It cannot be tested by any possible observation.

The claim is unfalsifiable — no possible observation could ever prove it wrong. Falsifiability is the key requirement for a scientific hypothesis.

The height of the plant

The dependent variable is what is measured as the outcome — here, plant height. The amount of fertiliser is the independent variable; water and temperature are controlled variables.

Plants grow better with more sunlight.

Only the sunlight claim makes a prediction you could actually check — you can grow plants in different light levels and see. The others cannot be tested by any possible observation.

Appeal to authority

The scientific method loop is: observe, question, hypothesise, predict, test, analyse, revise. Appealing to authority is the opposite of science — evidence takes priority over authority.

True

A hypothesis must be falsifiable — there must be some possible observation that could prove it wrong.

A hidden third factor, temperature, drives both.

This is a classic case of correlation without causation. Temperature rises in summer, which independently increases both ice-cream sales and swimming (and therefore drowning) — a hidden third factor drives both.

A control group given everything except the fertiliser

Without a control group — identical plants given everything except the fertiliser — you cannot tell whether the fertiliser caused the extra growth or the plants would have grown that tall anyway.

A well-tested framework that explains many observations

In science, a theory is a well-tested explanatory framework that unifies many observations and has survived repeated attempts to disprove it — not a hunch.

The uncertainty in the measurement

Every measurement has a limit to its precision. The $\pm 0.1$ reports the uncertainty, telling you both the value and how much to trust it.

A law describes what happens; a theory explains why it happens.

A scientific law describes what happens (often mathematically), while a theory explains why. Neither is 'just an idea' — both are strong products of science.

So expectation alone does not distort the result

The placebo group controls for the power of expectation. If the real treatment works better than the dummy, the effect is more likely to be genuine.

There is a correlation, but causation needs a controlled experiment.

The study shows correlation only. A hidden factor — such as family routine or overall health — could drive both. Establishing causation requires a controlled experiment ruling out alternatives.

Confidence that the result is reproducible and reliable

Repetition by independent teams is central to science. When different people, in different places, get the same answer, confidence in the result grows — a single result proves little.

Was this an experiment, or just two correlated numbers?

Correlation alone cannot establish causation. The first question is whether the evidence comes from a controlled experiment or merely from two variables moving together.

Is it morally right to test drugs on animals?

Science answers testable questions about the natural world. Moral, aesthetic and value-based questions belong to ethics, art and philosophy — recognising this boundary is part of scientific honesty.

Applying the same amount of water and light to both the experimental group with fertilizer and a control group without fertilizer.

The correct option is C because it ensures that the only variable affecting plant growth is the fertilizer itself, while all other conditions remain constant. This is crucial for determining the fertilizer's true effect.