Year 8 Science • AC9S8I03 • Authored homework
Measure with Useful Precision
Choose equipment and record data with suitable units, precision and consistency so measurements are useful evidence. Show reasoning in full sentences where useful, and check calculations or conclusions before finishing.
Part A
Short-answer questions
What is the difference between accuracy and precision?
Which tool is more suitable for measuring 25 mL of water: a beaker or measuring cylinder? Explain.
Record 3.456 cm to one decimal place and to two decimal places.
Why should units be written in every data table heading?
What is a parallax error when reading a scale?
Why are repeated measurements useful?
Give one example of a digital sensor used in science.
Explain why measuring to the nearest metre is not useful for a leaf length.
What should you do if one measurement is very different from the others?
Write a correct table heading for time measured in seconds.
Part B
Long-answer questions
A student measures reaction time with a stopwatch three times: 0.42 s, 0.45 s and 0.43 s. Calculate the mean and comment on precision.
Compare using a ruler, tape measure and laser measure for measuring a classroom. Which is most suitable and why?
Explain how to reduce measurement error when measuring the temperature change of water over 10 minutes.
A balance reads to the nearest 0.1 g. Explain what this tells you about precision and why it matters.
Design a measurement plan for plant growth over two weeks, including tool, units, frequency and table format.
Explain how poor measurement choices could make a fair investigation unreliable.
A student writes lengths as 12, 13 cm, and 0.14 m. Explain the problem and rewrite the data consistently.
Describe how to use repeated readings and averaging to improve confidence in results.
Choose suitable equipment to measure time, mass, length and temperature in a dissolving investigation. Justify each choice.
Evaluate whether a graph based on poorly labelled, inconsistent measurements can support a strong conclusion.
Part C
Research and understanding task
Find a real scientific instrument such as a microscope, thermometer, sensor, seismometer or data logger. Explain what it measures, its units, and why precision matters.