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A1.1 · Form scientific questions, predictions, and testable hypotheses

Learn to form scientific questions, predictions, and testable hypotheses through clear examples and targeted practice.

Ontario Grade 11 Physics

Scientific Investigation Skills and Career Exploration

Forming scientific questions, predictions, and testable hypotheses

Physics begins with curiosity, but curiosity alone does not tell us what to investigate. A useful scientific question points to something that can be observed or measured. A prediction states what you expect to happen. A testable hypothesis proposes an answer that can be checked with evidence. These are related, but they are not interchangeable. In this lesson, you will practise forming each one without treating a planned investigation or a simulation as if it had already produced real-world evidence.

What you will learn

1. From a topic to a scientific question

A topic is a broad area of interest, such as motion, sound, or circuits. A scientific question narrows a topic to something that could be investigated. For example, “How does a ramp affect a toy car’s motion?” is more focused than “What is motion?” The focused question points toward a change that can be made and an outcome that can be observed.
A variable is a factor that can change or take different values. In a question about a ramp and a toy car, the ramp’s steepness could be one variable. The car’s travel time over a marked section could be another. Naming these variables helps you decide whether a question is answerable with evidence.
A question is testable when you can describe what observations or measurements would help answer it. “Does ramp steepness affect the car’s travel time over a marked section?” is testable in principle: a student could vary steepness and record travel time. It does not claim that the investigation has been done or that any particular result was found.
Good questions are focused and clear about the situation. If several factors change at once, it may be difficult to know which one is linked to the outcome. For a fair comparison, plan to change the factor you are investigating while keeping other relevant conditions as similar as practical. This planning makes the evidence easier to interpret.

2. Prediction and hypothesis: related, but different

A prediction says what you expect to observe in a particular situation. It is often written as an “if … then …” statement. For example: “If the ramp is made steeper, then the car will take less time to cross the marked section.” The prediction gives an expected outcome. It does not, by itself, explain why the outcome should happen.
A hypothesis is a proposed explanation or answer that can be checked against evidence. For this example, a hypothesis could be: “Increasing the ramp’s steepness will reduce the car’s travel time over the marked section because the car will gain speed more quickly on the steeper ramp.” The explanation is a reasoned proposal, not a fact established by writing it down.
A testable hypothesis connects the change being investigated to an outcome that can be observed. It must be possible for evidence to support or fail to support the proposed connection. A hypothesis is not testable if it depends only on an opinion, uses unclear terms, or cannot be linked to any possible observation.
Before using a word such as “faster,” be clear about what you would observe or measure. In the example, the outcome is travel time across a marked section, recorded in seconds. The car’s direction along the ramp could also be described if direction matters to the question. Not every inquiry needs a numerical calculation; the key is to say what evidence would address the question.
A hypothesis does not need to be correct to be useful. Its value is that it makes a clear claim that can be checked. If the evidence does not support it, that is still useful information. It is important to report what was actually observed rather than changing the hypothesis afterward and presenting the new idea as the original one.

3. Plan for evidence before drawing conclusions

Before investigating, decide what would count as evidence. Evidence is information gathered by observing or measuring. In a planned ramp investigation, possible evidence could be recorded travel times for repeated trials at chosen ramp settings. Those are examples of data a student might collect; they are not results from a completed investigation.
A procedure is a planned sequence of actions for gathering evidence. It should make clear what factor will be changed, what outcome will be recorded, and which conditions should be kept similar. For the ramp example, a plan might use the same car, the same marked travel distance, and a consistent release method while testing selected ramp settings. This describes a proposed procedure only.
A simulation is a computer-based model of a situation. Its output is generated by the model and its settings. It can help explore a question, but simulated output is not a physical measurement from a real car. State clearly whether information came from direct observation, measurement, or a simulation.
A useful planning check is to ask: Could someone tell what to change, what to observe, and what evidence to record? If not, make the question or method more specific. Also ask whether the planned evidence could distinguish between the expected outcome and a different outcome. This prevents a question from being only a statement of belief.

4. A reliable way to write all three

Start with a topic, then name a possible change and an observable outcome. Turn those into a question. Decide what outcome you expect and write it as a prediction. Finally, propose a testable explanation or connection as a hypothesis. Check that the hypothesis matches the question and that a possible investigation could gather relevant evidence.
The pattern below is a writing aid, not a physics law. “If” identifies the factor being changed; “then” states the outcome to look for. A hypothesis can add a reason, but the reason must still connect to something that evidence can check.
For the toy-car example, the question asks whether ramp steepness is related to travel time. The prediction says which way the time is expected to change. The hypothesis proposes a reason for that expected connection. A different result could lead the student to reconsider the hypothesis, the procedure, or other factors that might have affected the observations.
Before accepting your own draft, read it as if you were a classmate asked to investigate it. Could that classmate identify the situation and the outcome? Is the expected result clear? Could observations or measurements provide evidence relevant to the claim? If the answer to any of these is no, revise the wording.
If change, then expected outcome.

Worked example

Example 1: Improve a broad question

A student is interested in sound and asks, “Is loud sound different?” Make the question more focused and testable without claiming that measurements have been made.
  1. Choose an observable change
    “Loud sound” is vague. A more specific question could compare the setting of a speaker’s volume control with a sound-level reading at a fixed location. The setting can be changed, and the reading can be recorded. This describes a possible investigation, not collected evidence.
  2. State the focused question
    Name the factor to change and the outcome to record. Keeping the speaker and measurement location fixed in the proposed plan would make the comparison easier to interpret.
  3. Separate plan from result
    A suitable question is: “How does the speaker’s volume setting affect the sound-level reading at a fixed location?” It can be investigated, but it does not report any result.
Answer: “How does the speaker’s volume setting affect the sound-level reading at a fixed location?”
Check: The question names a change and an observable outcome. It does not claim that a reading has already been taken.

Worked example

Example 2: Match a prediction to a question

A proposed inquiry asks whether changing the angle of a ramp affects how long a toy car takes to travel between two marks. Write a prediction that gives a clear expected result.
  1. Identify the change and outcome
    The ramp angle is the factor the plan changes. The time for the car to travel between fixed marks is the outcome. Time is recorded in seconds, but no value is assumed here.
  2. State an expected direction of change
    A prediction should say which way the outcome is expected to change. The following statement is an expectation to check, not a measured result.
  3. Write the prediction
    If the ramp angle is increased, then the car’s travel time between the marks is expected to decrease. The statement directly matches the proposed question.
Answer: If the ramp angle is increased, then the car’s travel time between the marks is expected to decrease.
Check: The prediction names the changed factor and the expected outcome. It gives no invented measurement or claim of experimental evidence.

Worked example

Example 3: Make a hypothesis testable

For the ramp inquiry, assess the statement “The car will be better on the steep ramp” and revise it as a testable hypothesis.
  1. Find the unclear wording
    “Better” does not identify an observable outcome. Different people could mean a shorter travel time, a longer distance, or something else. The statement cannot guide a clear evidence check.
  2. Connect the claim to evidence
    Use the outcome already named in the question: travel time between fixed marks. Propose a relationship between ramp angle and that time. A reason may be included, but it remains a proposed explanation until checked.
  3. Write the revised hypothesis
    A testable version is: “Increasing the ramp angle will reduce the car’s travel time between the marks because the car is expected to gain speed more quickly on the steeper ramp.” The proposed procedure would record times; no result is being reported.
Answer: Increasing the ramp angle will reduce the car’s travel time between the marks because the car is expected to gain speed more quickly on the steeper ramp.
Check: The revised claim identifies an outcome that can be recorded and a proposed reason. Evidence could support or fail to support it.

Common mistakes and how to avoid them

Treating a prediction and a hypothesis as the same thing.
Correction: A prediction states an expected observation. A hypothesis proposes an answer or explanation that can be checked. Write both so they address the same question.
Using vague words such as “better,” “stronger,” or “different” without saying what could be observed.
Correction: Name a clear outcome, such as a reading, a distance, or a time, and say how it could be observed or recorded.
Writing a question that asks only for an opinion or cannot be checked with evidence.
Correction: Revise it to identify an observable situation and evidence that could help answer it.
Writing a planned procedure as though it were a completed experiment.
Correction: Use future or conditional wording for a plan. Report measurements as evidence only if they were actually collected.
Calling a simulation result a physical measurement.
Correction: Identify simulated output as output from a model. Do not present it as an observation of a real-world event.

Lesson summary

Check your understanding

Question 1

Which is the most testable question?
  1. Is sound interesting?
  2. How does the speaker’s volume setting affect a sound-level reading at a fixed location?
  3. Why is sound always better when it is loud?
  4. correctIndex: 1,
Show answer and explanation
How does the speaker’s volume setting affect a sound-level reading at a fixed location?
It identifies a change and an observable outcome that could be recorded.

Question 2

A student writes, “If the ramp is made steeper, the car is expected to take less time between the marks.” What is this statement?
  1. A prediction
  2. A recorded measurement
  3. A simulation
  4. correctIndex: 0,
Show answer and explanation
A prediction
It states an expected outcome. It does not report evidence or identify a simulation.

Question 3

A computer model produces a value for a car’s travel time. How should the value be described?
  1. A physical measurement collected from a real car
  2. Output generated by the simulation
  3. Proof that the hypothesis is correct
  4. correctIndex: 1,
Show answer and explanation
Output generated by the simulation
A simulation produces model output, not a physical measurement. One output alone does not prove a hypothesis.

Key terms

Scientific question
A focused question about a situation that can be investigated using observations or measurements.
Variable
A factor that can change or take different values.
Prediction
A statement of what is expected to be observed in a particular situation.
Hypothesis
A proposed answer or explanation that can be checked against evidence.
Evidence
Information gathered through observation or measurement that can help answer a question.
Procedure
A planned sequence of actions for gathering evidence.
Simulation
A computer-based model that generates output from its setup and settings.

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Published by DoAssignment. This AI-assisted lesson follows Ontario Grade 11 Physics (SPH3U), expectation A1.1. It is a study resource, not an official curriculum publication.

Before publication, the draft is checked for structure, mathematical or chemical notation, calculations, course boundaries, and readability, and then requires administrator approval. Errors can still occur, so corrections are welcomed.

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