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Lesson 14 ~35 min Unit 4 · Data Science +85 XP

Mini Data Investigation

In 2022, Year 9 students at Wollongong High tested 3 paper towel brands across 20 trials and published their findings in the school science journal — genuine scientific process in 60 minutes.

Today's hook: In 2022, a Year 9 class at Wollongong High School of the Performing Arts ran a proper investigation in one 60-minute lesson. They tested 3 brands of paper towel, did 20 trials each, built a data table, graphed the results and wrote a 150-word conclusion. They followed the same steps that professional scientists use — question, prediction, fair test, data collection, analysis, communication. Today you do the same. You have one lesson, basic equipment, and a real question to answer. The only thing standing between you and a real scientific result is good planning — so what is your question?
0/5QUESTS
Think First
warm-up

You have one lesson to investigate a question about your classroom or school using only simple equipment like a stopwatch, ruler, thermometer or survey.

What question could you realistically answer? What data would you need, and how would you make sure your test is fair?

Write your prediction in your book before reading on.
Cross-lesson links: This mini investigation is where you put the whole unit to work — you'll need the fair-test variables from Lesson 3, the data tables from Lesson 4, the graph skills from Lesson 5, and the claims-evidence-reasoning structure from Lesson 11 all in one session.
1
Choosing Your Question
+5 XP

Pick up a ruler. You could measure how far a ball rolls, how tall a stack of books is, or how much a rubber band stretches under different loads. Each of those is a starting observation — something you can see and measure. Now turn it into a question: does the surface type change how far the ball rolls? A good investigation starts with a clear, specific question like that, one that can be answered with data. Examples include: 'Does the height of a ramp affect how far a ball rolls?' or 'Which type of paper towel absorbs the most water?'

Once you have a question, write a prediction or hypothesis so you know what outcome you expect and why.

Quick check — which of these is a testable scientific question?
2
Planning the Fair Test
+5 XP

Identify your independent, dependent and controlled variables before you begin. Decide how many repeats you will do and what equipment you need.

Design your data table in advance with headings and units. Think about safety and ethics, even in simple classroom investigations.

True or false?
In a fair test, you should change both the independent variable and one controlled variable at the same time.
3
Collecting and Recording Data
+5 XP

Follow your plan carefully and record all data as you go, even if it looks wrong. Anomalous results are part of real science and should be investigated, not hidden.

Take your time with measurements. Rushing leads to random errors. If you are working in a group, make sure everyone uses the same technique.

Quick check — what should you do with an anomalous result?
4
Spot the Trap
heads-up

Wrong: A mini investigation is just messing around with equipment.

Right: Even small investigations need clear questions, controlled variables, repeated trials and honest analysis to produce meaningful results.

Wrong: If your results do not match your prediction, the investigation failed.

Right: Unexpected results are still valuable. They may reveal errors, new questions or genuine phenomena you did not anticipate.

Wrong: Changing the method halfway through data collection.

Right: Changing your procedure during the experiment introduces uncontrolled variables. If you must change something, start again with the new method consistently.

Wrong: Only recording data that supports the hypothesis.

Right: All data must be recorded and reported, even if it is surprising or unwelcome. Cherry-picking is scientifically dishonest.

5
Analysing and Presenting
+5 XP

Calculate averages, identify trends and create appropriate graphs from your data. Look for patterns and consider whether your results support or contradict your hypothesis.

Write a brief report with sections for aim, method, results, discussion and conclusion. Be honest about limitations. Self-criticism makes your work more credible, not less.

True or false?
A good scientific report includes an honest discussion of limitations and anomalies.
Speed round +6 XP

True or false? Tap as fast as you can. Build a streak.

Q · 1 / 6 Streak · 0 Score · 0

A mini investigation does not need a clear question or hypothesis.

How are you completing this lesson?

Revisit Your Thinking
reflect

Revisit your chosen question from the opening scenario.

Write a complete plan for your mini investigation, including the question, variables, method outline and how you will present your results.

Write your updated thinking in your book.
1
What is the first step in any scientific investigation?
+10 XP
2
Why is it important to decide on controlled variables before starting data collection?
+10 XP
3
What should you do with data that does not support your hypothesis?
+10 XP
4
How many repeats are generally recommended for a classroom investigation?
+10 XP
5
Which best describes the purpose of a hypothesis?
+10 XP
Check Your Understanding
short answer

1. Write one testable question that could be investigated in a classroom using a stopwatch and a ball.

Write your answer in your book.

2. Why should you design your data table before starting the experiment?

Write your answer in your book.

3. What should you do if your results do not match your hypothesis?

Write your answer in your book.
Show Your Working
12 marks total
5 MARKS

SA1. Plan a mini investigation to test how the amount of salt affects the boiling point of water. Identify the variables, describe the method and explain how you would ensure a fair test. (5 marks)

Hint: Consider what must stay the same and what you will measure.

Write your answer in your book.
4 MARKS

SA2. Explain why repeating trials and calculating a mean is important in a mini investigation, using the concepts of random error and reliability. (4 marks)

Write your answer in your book.
3 MARKS

SA3. Describe how you would present the results of your mini investigation to make them clear and convincing to another student. (3 marks)

Write your answer in your book.
Comprehensive Answers

Quick Check

1. C — Every investigation starts with a clear, testable question.

2. B — Controlled variables ensure the test is fair and the cause of any effect can be identified.

3. C — All data must be reported honestly and discussed.

4. B — At least three repeats are recommended for a classroom investigation.

5. B — A hypothesis makes a testable prediction that guides the investigation.

Check Your Understanding Model Answers

1. Any reasonable testable question using a stopwatch and a ball, e.g. 'Does the height of a ramp affect how far a ball rolls?'

2. Designing the data table beforehand ensures you record the right variables with correct units, helps you stay organised during the experiment, and prevents you from forgetting to measure something important.

3. Report the results honestly, discuss possible reasons such as random error or uncontrolled variables, and consider whether the hypothesis needs to be revised or the experiment repeated.

Show Your Working Model Answers

SA1 (5 marks): Independent variable: amount of salt [1]. Dependent variable: boiling point (temperature) [1]. Controlled variables: volume of water, heat source, container, thermometer [1]. Method: add measured amounts of salt to equal water volumes, heat to boiling, record temperature, repeat [1]. Fair test: only change salt amount, keep all other variables constant [1].

SA2 (4 marks): Random errors occur in every measurement [1]. Repeating trials lets you spot anomalous results [1]. Calculating a mean gives a more reliable value than a single measurement [1]. Reliability means another scientist would obtain a similar result using the same method [1].

SA3 (3 marks): Present results in a table with clear headings and units [1]. Use an appropriate graph to show trends [1]. Write a brief report with aim, method, results, discussion and conclusion [1].

R
Quick Review

Investigation

A systematic process of collecting and analysing data

Hypothesis

A testable prediction about the expected outcome

Fair test

Only the independent variable is changed

Data collection

Gathering measurements or observations

Analysis

Identifying patterns, trends and relationships

Presentation

Communicating findings through reports and graphs

Test Your Knowledge
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