1.4 - Scientific Investigation in Biology

Scientific Investigation

• A scientific investigation proves the validity of a hypothesis.
• Design an experiment to solve a problem using scientific investigation methods.

Steps in a Scientific Investigation

1. Identify a problem that can be tested using a scientific investigation.
2. Form a hypothesis.
3. Identify and control variables and the data collection method.
4. Plan and carry out the scientific investigation.
5. Collect data.
6. Interpret data and results through scientific reasoning.
7. Form a conclusion.
8. Write a report.

Experimental Report Framework

Problem Statement

• State the problem as a testable question.
• Example: What is the effect of a vigorous activity on a pupil’s pulse rate?

Hypothesis

• State the expected relationship between the variables.
• Example: The pupil’s pulse rate increases after a vigorous activity.

Variables

• Manipulated variable: vigorous activity.
• Responding variable: pupil’s pulse rate.
• Fixed variable: pupil.

Materials, Apparatus and Specimen

• Apparatus: stopwatch.
• Specimen: pupil.

Procedure

1. Count the pupil’s pulse for one minute before the activity by placing two fingers on the wrist.
2. Ask the pupil to carry out a vigorous activity for three minutes.
3. Count the pupil’s pulse again for one minute after the activity.
4. Record the results in a table.

Results and Discussion

• Record the pulse rate before and after the vigorous activity.
• State the relationship between pulse rate and vigorous activity.
• Explain why pulse rate increases after vigorous activity.

Conclusion and Report

• State whether the results support the hypothesis and whether the hypothesis is accepted or rejected.
• Prepare a complete report of the experiment.

Safety Precautions

• Keep the pupil seated quietly while measuring the pulse rate.
• Pupils with respiratory or cardiovascular problems must not take part in the activity.