Science Skills

What is the scientific method?

A systematic process for investigating questions using evidence.

What is an aim?

A statement explaining what an experiment investigates.

What is a hypothesis?

A testable prediction explaining the expected result.

What should a hypothesis include?

A prediction and a scientific reason for it.

What is an independent variable (IV)?

The factor deliberately changed by the experimenter.

What is a dependent variable (DV)?

The factor measured or observed in response to the IV.

What is a controlled variable (CV)?

A factor kept the same to ensure a fair test.

What makes an experiment a fair test?

Change only the IV; keep other relevant factors constant.

In a temperature-versus-reaction-time test, what is the IV?

The temperature of the reactants.

In a temperature-versus-reaction-time test, what is the DV?

The time taken for the reaction.

Name two controlled variables in a reaction-rate test.

The amount of reactant and the volume of acid.

What is a scientific method/procedure?

Numbered, clear steps explaining how to repeat an experiment.

How should each method step begin?

With an action verb, such as measure, pour or record.

What is a risk assessment?

Identifying hazards and describing how to reduce the risks.

Why wear safety goggles in a chemical experiment?

To protect eyes from splashes and flying particles.

How should a scientific diagram be drawn?

Use clear pencil lines, labels and no unnecessary shading.

What does a results table need?

Clear column headings, units and organised measurements.

What belongs on the x-axis?

The independent variable (IV).

What belongs on the y-axis?

The dependent variable (DV).

What must each graph axis include?

The variable name and its units.

What makes an appropriate graph scale?

Equal numerical intervals that use the graph space well.

When should you draw a line of best fit?

When showing the overall trend in scattered numerical data.

Should a line of best fit connect every dot?

No. It follows the overall pattern rather than joining every dot.

What is reliability in an experiment?

Obtaining consistent results when trials are repeated.

How can reliability be improved?

Repeat the experiment and calculate an average.

What is accuracy?

How close a measurement is to the true or accepted value.

How can accuracy be improved?

Use suitable calibrated equipment and read it correctly.

What is validity in an experiment?

Whether the investigation fairly tests the question asked.

How can validity be improved?

Control other variables and measure the intended DV.

What does a conclusion need?

The finding, supporting data and whether the hypothesis was supported.

What belongs in a discussion?

Trends, scientific explanation, errors and possible improvements.

What does a positive correlation mean?

As one variable increases, the other generally increases.

What does a negative correlation mean?

As one variable increases, the other generally decreases.

In the skateboard graph, what is the IV?

Mass on the skateboard, measured in kilograms (kg).

In the skateboard graph, what is the DV?

Friction force, measured in newtons (N).

What is the skateboard result at 20 kg?

6 N of friction force.

What is the skateboard result at 30 kg?

8 N of friction force.

What trend does the skateboard experiment show?

More mass generally produces greater friction force.