Practical 2

Overview

This lesson gives you another chance to practise planning and carrying out an investigation. The main focus is timing: how to make timing results as accurate as possible and how to write a conclusion that actually uses the data.

What You Need to Know

• Timing experiments can be affected by reaction time, so repeated readings are important.
• A good method says what to change, what to measure, what to keep the same, and how to repeat the measurement.
• The range of a quantity is the difference between the largest and smallest values.
• A conclusion should compare results using clear language such as greater than, less than, faster, slower, increases, or decreases.
• A strong conclusion uses evidence from the results instead of only describing what you expected.

How to Work Through It

1. Start by identifying the timing measurement and the main source of uncertainty.
2. Plan a method that includes repeats and any control variables.
3. Record results clearly and calculate a range or average where needed.
4. Write a conclusion that compares results and refers directly to the data.

Check Your Understanding

• How can you reduce the effect of reaction time in a timing experiment?
• What does range tell you about a set of results?
• Which words help you compare two results clearly?
• Does your conclusion include evidence from the results?

Common Mistakes

• Taking only one timing measurement and treating it as reliable.
• Writing a conclusion that is too vague, such as “it changed”, without saying how.
• Confusing range with average.
• Forgetting to keep other variables the same when testing one variable.

Next Steps

• Complete the timing homework to practise writing methods and conclusions.
• Keep using comparison language whenever you describe results in future practicals.