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A1.5 · Conduct inquiries while controlling variables and recording observations

Learn to conduct inquiries while controlling variables and recording observations through clear examples and targeted practice.

Ontario Grade 10 Science

Scientific Investigation and Careers

Conducting inquiries by controlling variables and recording what happens

In Grade 9, you learned to observe materials and events and to record information. An inquiry uses those skills to answer a focused question. For a fair comparison, change one chosen factor while keeping other relevant conditions the same. Record what actually happens rather than what you expect. This lesson focuses on planning that comparison and making a useful record. The examples use safe, hypothetical observations; they are not claimed laboratory results.

What you will learn

Describe a question that can be investigated by observing or comparing results.
Identify the factor changed, the result observed, and the conditions kept the same.
Record observations clearly, with labels, units when needed, and enough detail to compare trials.
Use recorded observations as evidence while recognizing what they do and do not show.

1. From a question to a fair comparison

An observation is information gathered by noticing or measuring something. You might describe a colour, count objects, or measure a length with an appropriate tool. A result is what you observe during an inquiry. Keep observations separate from explanations: “the paper looks darker” is an observation, while “water caused the change” is a possible explanation.

An inquiry begins with a question that can be explored through observations. A broad question such as “What happens to paper?” needs more focus. A clearer question is “Does the amount of water added affect how dark this paper looks?” It names a factor to compare and a result to observe.

A variable is a factor that can change. In a simple comparison, identify three roles. The changed variable is the factor you deliberately vary. The responding variable is the result you observe or measure. Controlled variables are relevant conditions you keep the same so the comparison is fair. These names help you plan; they do not replace careful observations.

For the paper question, the amount of water is changed. The paper’s appearance is observed. The paper type, size, lighting, and time allowed for drying could affect the appearance, so keep them as similar as possible. If several important conditions change at once, it becomes harder to tell which change is connected to a different result.

Make the question focused and observable.
Change one chosen factor in a comparison.
Keep other relevant conditions the same.
Describe what you see before offering an explanation.

2. Plan, observe, and record

Before starting, decide what you will compare and how you will record the result. Use the same observation method for each condition. For example, if appearance is judged by looking, use the same lighting and the same description scale each time. A scale is a set of labels used consistently, such as “light,” “medium,” and “dark.” It is a record of judgment, not a precise measurement.

A useful record makes clear what each entry means. Give a table a descriptive title. Label each column, and include units when you measure quantities such as length or time. Write observations as they happen, not later from memory. Record unexpected outcomes too. Do not change an observation to match what you predicted.

If a result is difficult to judge, say so. For example, write “between light and medium” rather than forcing it into a category that does not fit. If you use numbers, describe what was measured and with what unit. A number without a label or unit may be hard to interpret.

A prediction is what you think may happen. It can help you plan what to watch for, but it is not evidence that the outcome happened. Evidence is the recorded observation that relates to the question. A conclusion should match that evidence and should not claim more than the inquiry can show.

Use the same observation method across conditions.
Label records so another reader can understand them.
Record actual observations, including unexpected ones.
Keep predictions, observations, and explanations distinct.

3. Reading a record with care

A comparison is only useful when you know what changed and what stayed the same. Look across the recorded entries and describe a pattern only if the observations support it. A pattern might be that one condition was repeatedly associated with a particular result. A single observation can suggest a possibility, but it may not be enough to support a broad claim.

Conditions kept the same make a comparison fairer, but they do not guarantee perfect results. Observations can be uncertain. Lighting may shift, a measuring tool may be difficult to read, or two people may describe a colour differently. Note such limits instead of hiding them.

The goal is not to force a definite answer. If the observations are mixed or unclear, report that. You can say that the recorded evidence does not show a clear pattern. Honest uncertainty is more useful than a confident claim that the record cannot support.

Connect any conclusion to the observations recorded.
Mention unclear observations or conditions that may affect comparison.
Do not treat one result as proof of a general rule.

4. Safe and responsible inquiry

Choose a method that is suitable for the question and follow the teacher’s directions. Use only approved materials and equipment. Do not taste or directly handle unknown substances. Wear any protective equipment the teacher requires, and report spills, breakage, or discomfort promptly.

Safety is part of planning, not an afterthought. If a comparison would require an unsafe action, do not try it. Ask the teacher for a safe alternative. A useful inquiry is one that gathers relevant observations while protecting everyone involved.

When sharing results, state whether information is hypothetical or actually observed. In this lesson’s examples, all data are hypothetical. Labelling them prevents a made-up illustration from being mistaken for experimental evidence.

Follow teacher directions and use approved materials.
Do not carry out unsafe tests.
Clearly identify hypothetical information.

Hypothetical paper appearance record

Water added	Observation after drying
Small amount	Light
Medium amount	Medium
Larger amount	Dark

Hypothetical toy-car record

Starting point	Trial	Distance travelled (cm)
Lower	1	42
Lower	2	45
Higher	1	61
Higher	2	59

Worked example

Comparing paper appearance

A class asks whether adding different amounts of water changes how dark a small paper square looks after drying. Plan a fair comparison and interpret the hypothetical record.

Name the comparison
The changed variable is the amount of water. The responding variable is the paper’s appearance after drying. Keep the paper type and size, lighting, and drying time the same. These conditions matter because they could also affect how the paper looks.
Choose a record
Use the same labels for every square and inspect them under the same lighting. The following entries are hypothetical, not measured results.
Interpret the record
The hypothetical entries suggest that the squares receiving more water looked darker in this comparison. The record supports a description of this set of observations. It does not establish that every paper will behave the same way.

Answer: A fair plan changes only the amount of water, keeps relevant conditions similar, and records appearance in the same way. The hypothetical record suggests a pattern for the squares compared, but does not justify a universal claim.

Check: The changed amount is the factor being compared; paper size, paper type, lighting, and drying time are held steady.

Worked example

Comparing how far a toy rolls

A student wonders whether a toy car rolls farther from a higher starting point. Explain what to control and how to record the observations. Use the hypothetical distances below.

Identify the variables
The starting height is the changed variable. The distance from the ramp’s end to the car’s stopping point is the responding variable. Use the same car, ramp surface, release method, and floor surface so these conditions do not become other possible reasons for a difference.
Record each result
Measure from the same starting mark to the stopping point and label the distance in centimetres. These are hypothetical observations for practising how to read a record.
State what the evidence shows
Both hypothetical trials from the higher point have a greater recorded distance than both trials from the lower point. This supports a pattern in these observations. It is still careful to say “in these trials,” because the record covers only these comparisons.

Answer: Keep the car, surfaces, release method, and measurement points the same. The hypothetical record shows larger distances for the higher starting point in these trials, but the conclusion should stay limited to the observations made.

Check: Repeating observations can show whether a pattern appears more than once; recording each result prevents a single value from hiding differences.

Worked example

Comparing paper-towel absorbency

A group wants to compare how much water two brands of paper towel absorb. Describe a controlled comparison and assess a hypothetical record where one square of each brand is tested once.

Make the comparison fair
The towel brand is the changed variable. The amount absorbed is the responding result. Use equal-sized squares, the same starting amount of water, the same contact time, and the same way of judging the remaining water. Follow the teacher’s safe procedure.
Assess the limited record
Suppose the hypothetical record says Brand A absorbed more than Brand B in one trial. That entry is an observation for those tested pieces. It is not enough to know whether the difference would appear again, and the record should not be described as repeated evidence.
Report the limitation
State the result and its limit: one tested square of Brand A appeared to absorb more in this hypothetical comparison. Do not claim that Brand A always absorbs more. If the teacher approves, further fair comparisons could help show whether the same pattern is observed again.

Answer: A fair test keeps square size, starting water amount, contact time, and observation method consistent. One hypothetical comparison suggests a difference for the tested pieces, but cannot establish that the difference will always occur.

Check: The result is limited because only one square of each brand was included in the hypothetical record.

Common mistakes and how to avoid them

Changing several conditions at once and then crediting one change for the result.

Correction: Choose one factor to change and keep other relevant conditions the same.

Writing a prediction as though it were an observation.

Correction: Record what happened. Keep predictions and explanations separate from observed evidence.

Leaving out labels, units, or the conditions being compared.

Correction: Use clear titles and column labels, include units for measurements, and identify each condition.

Making a broad claim from one observation.

Correction: Describe the result narrowly and say when the record is too limited to show a clear pattern.

Leaving out an unexpected result because it does not match a prediction.

Correction: Record unexpected observations honestly. They are part of the evidence.

Lesson summary

A focused inquiry asks about an observable result.
Identify what you change, what you observe, and what relevant conditions you keep the same.
Use the same method and clear labels when recording observations.
Base conclusions on the record and state its limits.
Use only teacher-approved, safe procedures.

Check your understanding

Question 1

A student compares two plants but gives one more water and places it in brighter light. Why is the comparison difficult to interpret?

Two conditions changed, so the record cannot clearly connect a result to just one change.
The plants were observed instead of predicted.
A fair comparison must have no observations.
Bright light is always the responding variable.

Show answer and explanation

Two conditions changed, so the record cannot clearly connect a result to just one change.

Water and light both changed. Either could be related to a difference, so a clearer comparison changes one chosen factor and keeps other relevant conditions the same.

Question 2

Which entry is the clearest observation record?

The second strip was better.
I knew the blue strip would win.
Strip B looked darker than Strip A under the same lamp.
Strip B changed because it was stronger.

Show answer and explanation

Strip B looked darker than Strip A under the same lamp.

This entry describes what was seen and gives a relevant condition. The other options are vague, predictions, or explanations rather than a direct observation.

Question 3

A hypothetical comparison records one result for each of two materials. What is the most careful conclusion?

The material with the larger result always performs better.
The record shows a difference in these two observations, but more evidence would be needed for a broader claim.
The observations should be ignored because there was only one comparison.
The result proves that all materials of that type behave the same way.

Show answer and explanation

The record shows a difference in these two observations, but more evidence would be needed for a broader claim.

The record can be described, but one observation for each material is limited evidence. A broad claim would go beyond what was observed.

Key terms

Observation: Information gathered by noticing or measuring something.
Inquiry: A planned way to explore a question by gathering observations.
Variable: A factor that can change.
Changed variable: The factor deliberately varied in a comparison.
Responding variable: The result observed or measured.
Controlled variable: A relevant condition kept the same during a comparison.
Evidence: Recorded observations used to support a statement about an inquiry.
Prediction: A statement about what may happen, made before the result is observed.

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About this lesson and its review

Published by DoAssignment. This reviewed lesson follows Ontario Grade 10 Science (SNC2D), expectation A1.5. It is a study resource, not an official curriculum publication.

Before publication, content is checked for structure, mathematical or chemical notation, calculations, course boundaries, and readability. Errors can still occur, so corrections are welcomed.

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