Scientific method: six steps from a question to a result

The steps scientists take

Scientists take specific steps for scientific work. These steps are the scientific method; in biological research they are called the biological method. There are six: problem, observation, hypothesis, deduction, experiments, results.

1. Recognition of a problem: a biologist notices plants growing taller than usual and asks, "What factors are responsible for the increased growth?" 2. Observations: made with the five senses and by reading previous research.

Observations are qualitative (no numbers, like a flower's colour and texture) or quantitative (numbers, like the birds in a tree). Your book says quantitative ones are more accurate: invariable, measurable and recorded in numbers.

3. Hypothesis: a tentative answer to the problem. 4. Deduction: a logical "if-then" result of the hypothesis. 5. Experiments: the most basic step, testing every hypothesis. 6. Results: data summarised with statistics and graphs, then published and shared.

Order: problem → observations → hypothesis → deduction → experiments → results. The deduction is the bridge between hypothesis and experiment.

Key terms

Hypothesis

A testable statement that may answer the scientific problem.

Deduction

The logical result expected if the hypothesis is true.

Quantitative observation

A measurement that can be expressed as a quantity.

Control group

The setting that keeps the normal condition, for comparison.

Short questions with model answers

1. Q1. A plant has discoloured leaves and stunted growth. Take it through hypothesis, deduction and experiment.

   • Hypothesis: the symptoms are caused by a deficiency of iron in the soil.
   • Deduction: if iron deficiency is the cause, then adding iron will improve the leaves and growth.
   • Experiment: add iron to one plant; leave a similar plant without it.

   If only the iron-fed plant recovers, the hypothesis is supported; if not, it is rejected.

2. Q2. Exercise A Q7: which is NOT a characteristic of the scientific method?

   • It relies on evidence, formulates hypotheses, needs rigorous testing.
   • "Hypothesis will always be correct."

   (c) Hypothesis will always be correct.

Common mistakes

• ✗ Jumping from hypothesis straight to experiment.

  ✓ Deduction comes between them: it says what the experiment should show (Exercise A Q6).

• ✗ Calling the plant that gets carbon dioxide the experimental group.

  ✓ The experimental group has the factor removed; the control keeps normal conditions.

• ✗ Calling the colour of a flower a quantitative observation.

  ✓ No number, so it is qualitative; counting birds is quantitative.

MCQs

1. 1. Which step comes between making a hypothesis and doing experiments? (Exercise A Q6)

   1. (a) Making observations
   2. (b) Making deductions
   3. (c) Summarizing results
   4. (d) Analysing data
   Show answer

   (b) Deduction predicts what the experiment should show.

2. 2. Choose the correct sequence of steps. (Exercise A Q8)

   1. (a) Observations, hypothesis, law, theory
   2. (b) Hypothesis, observations, deduction, experiments
   3. (c) Law, theory, deduction, observations
   4. (d) Observations, hypothesis, deduction, experiments
   Show answer

   (d) The book's order on p. 14.

3. 3. "The number of birds in a tree" is:

   1. (a) A quantitative observation
   2. (b) A qualitative observation
   3. (c) A hypothesis
   4. (d) A deduction
   Show answer

   (a) It is expressed as a number (p. 15).

4. 4. Experiments are very important because a researcher: (Exercise A Q10)

   1. (a) Always gets correct results
   2. (b) Is sure to prove the hypotheses
   3. (c) Disproves many hypotheses and gets some proved
   4. (d) Gets a chance to work in the laboratory
   Show answer

   (c) One hypothesis is proved and the alternates are rejected (p. 16).

5. 5. In the carbon dioxide experiment, the plant given no carbon dioxide is the:

   1. (a) Control group
   2. (b) Experimental group
   3. (c) Hypothesis
   4. (d) Result
   Show answer

   (b) The factor is removed from the experimental group (p. 16).

Quick revision

• Six steps: problem, observations, hypothesis, deduction, experiments, results.
• A hypothesis is a testable, disprovable tentative answer; a deduction is its if-then result.
• Experiments compare an experimental group with a control group.