Planning a Fair Test: Variables, Tables and Graphs — Answers
Answer sheet with model answers and success criteria for the Year 6 working scientifically worksheet.
Success TutoringWorksheetsAnswer sheetYear 6 · Science · Working ScientificallyPlanning a Fair Test: Variables, Tables and Graphs — Answers
Part A: Planning an investigation
Read the passage. Then circle the best answer.
A fair test changes only one thing and keeps everything else the same.
The independent variable is the one thing you change on purpose. The dependent variable is what you measure to see the effect. The controlled variables are everything you keep the same.
Scientists repeat each test (usually three times) and find the average: add the results and divide by how many there are. This makes results more reliable.
Put the independent variable in the first column of your results table. Use a line graph when the independent variable is a measurement that can change smoothly, such as height or temperature. Use a bar graph (also called a column graph) when it is a set of separate groups, such as types of ball.
A conclusion says what you found out, using your data: “As ___ increased, ___ increased.”
- Anone
- Bone
- Ctwo
- Das many as possible
Answer: one
Change only one variable. Then any difference in the results is caused by that one change.
- Athe drop height
- Bthe type of ball
- Cthe bounce height
- Dthe floor
Answer: the bounce height
The dependent variable is what you measure — the bounce height.
- ATo make the results more reliable and spot mistakes.
- BTo make the test take longer.
- CTo change the variables.
- DBecause the first result is always wrong.
Answer: To make the results more reliable and spot mistakes.
Repeating and averaging smooths out small measuring errors and shows up any odd results.
- A28 cm
- B31 cm
- C29 cm
- D30 cm
Answer: 30 cm
Add them and divide by 3: (28 + 31 + 31) ÷ 3 = 90 ÷ 3 = 30 cm.
- Aa line graph
- Ba pie chart
- Ca picture graph
- Da bar graph of ball colours
Answer: a line graph
Drop height is measured in numbers that go up smoothly, so a line graph shows the trend best.
Part B: Variables
Answer: independent
Answer: controlled
Answer: Any two of: the same ball, the same floor surface, dropping (not throwing) the ball, measuring from the bottom of the ball, the same person measuring.
Part C: True or false?
Write True or False.
Answer: False
If two things change, you cannot tell which one caused the difference.
Answer: True
The table then reads from what you changed to what you measured.
Answer: True
Types of ball are separate groups, so a bar (column) graph suits them.
Part D: Working scientifically: Tom's bouncing-ball results
Use Tom's results to answer. Show your working.
Tom dropped the same tennis ball onto the same floor from three heights and measured the bounce three times at each height.
50 cm drop: 30 cm, 47 cm, 30 cm · 100 cm drop: 56 cm, 60 cm, 58 cm · 150 cm drop: 86 cm, 90 cm, 88 cm
Answer: 58 cm ((56 + 60 + 58) ÷ 3 = 174 ÷ 3 = 58).
Answer: The 47 cm trial at 50 cm drop height — it is much higher than the other two (30 cm, 30 cm). Tom should repeat that trial.
Answer: 88 cm ((86 + 90 + 88) ÷ 3 = 264 ÷ 3 = 88).
Model answer: As the drop height increased, the bounce height increased. When the ball was dropped from 100 cm it bounced 58 cm on average, and from 150 cm it bounced 88 cm. The bounce was always a little more than half the drop height.
Success criteria:
- States the pattern (as drop height increased, bounce height increased)
- Quotes average values from the data
- Any extra insight, e.g. bounce about 60% of drop height
Marking tips
- Give credit for correct method even when the final answer slips — the working shows where the thinking went right.
- For open-ended tasks, use the success criteria as a checklist rather than looking for one "right" answer.
- Celebrate what went well first, then pick one thing to work on next.