Practical skills

What should you include when planning an experiment?

• Aim: What you are investigating.

• Hypothesis: A prediction based on prior knowledge.

• Variables: Independent, dependent, and control variables.

• Method: Step-by-step procedure.

• Equipment: List all apparatus needed

What is a control variable?

A factor kept constant to ensure a fair test.

What is an independent variable?

The factor you change in an experiment.

What is a dependent variable?

The factor you measure in response.

What is a control variable?

Factors you keep the same to ensure a fair test.

Why is accurate measurement important?

Ensures reliability and allows correct conclusions.

Name ways to improve accuracy

• Repeat measurements and calculate a mean.

• Use appropriate equipment (e.g., pipettes, calibrated rulers).

• Measure at the same point each time.

How should data be recorded?

Clearly in tables, with units, and headings.

How should data be presented?

• Tables for raw data.

• Graphs for trends:

  • Line graphs → continuous data.

  • Bar charts → discrete/categorical data.

  • Scatter graphs → correlation.

What must graphs include?

Title, labeled axes, units, points plotted accurately, line of best fit if appropriate.

How do you analyse data?

Look for patterns, trends, and anomalies.

How do you draw a valid conclusion?

Relate results to your hypothesis and scientific knowledge.

What is an anomaly?

A result that does not fit the pattern. Should be repeated or ignored with justification.

What is reliability?

The consistency of results when repeated.

What is repeatability?

Obtaining the same results when the same person repeats the experiment.

What is reproducibility?

Obtaining the same results when someone else repeats the experiment.

How can reliability and accuracy be improved?

Use more samples, precise equipment, controlled variables, and repeated trials.

Why is risk assessment important?

To identify hazards, reduce risks, and protect yourself and others during experiments.

Give examples of safety precautions in biology practicals.

• Wear goggles, gloves, lab coat.

• Tie back long hair.

• Handle chemicals and microorganisms safely.

• Dispose of waste correctly.

Name some key Triple practical investigations.

• Measuring enzyme activity (temperature/pH effects).

• Investigating photosynthesis (e.g., oxygen production by pondweed).

• Fieldwork: quadrats, transects, measuring abiotic factors.

• Osmosis experiments (potato cores in different sucrose concentrations).

What is the required approach for Triple practicals?

• Plan carefully with variables controlled.

• Repeat for reliability.

• Present data clearly.

• Draw conclusions supported by evidence.