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A1.2 · Choose suitable equipment, materials, methods, and procedures

Learn to choose suitable equipment, materials, methods, and procedures through clear examples and targeted practice.

Ontario Grade 11 Physics

Scientific Investigation Skills and Career Exploration

A practical guide to planning a physics investigation

A physics investigation begins before anyone takes a measurement. You first need to understand what question you are trying to answer. Then you choose equipment, materials, a method, and a procedure that fit that question. A method is the general way you will gather evidence. A procedure is the ordered set of steps you will follow. Suitable choices make the evidence relevant and the work practical and safe. This lesson focuses on making those choices; it does not claim that any proposed investigation has been carried out.

What you will learn

1. Start with the question and the quantities

A quantity is something that can be measured or counted, such as length, time, or mass. Before choosing equipment, identify what quantity the question asks you to compare or determine. Also identify what you will change and what you will observe or measure. Keep the question narrow enough that your chosen method can provide relevant evidence.
Review the difference between a scalar and a vector. A scalar has a size and unit, such as a time of 2.0 s2.0\ \mathrm{s}. A vector has size, unit, and direction, such as a displacement of 2.0 m2.0\ \mathrm{m} east. If your question involves direction, select a method and recording plan that preserve it. Do not record a vector as a number alone.
Next, list the equipment and materials the method needs. Equipment is used to measure or carry out a task, such as a ruler or stopwatch. Materials are the objects or substances being investigated, such as a cart or a spring. Check that each item directly supports the question. Avoid adding equipment that does not improve the evidence or the safety of the procedure.

2. Match equipment to the measurement

Consider three practical features when choosing measuring equipment: range, scale, and precision. Range is the span of values the instrument can measure. Scale is the set of marks or display increments used to read it. Precision describes how finely the instrument can distinguish readings. A tool with too small a range may not measure the planned quantity. A very coarse scale may make it hard to compare small changes.
Think about the size of the quantity before choosing. A metre stick may suit a length of a few tens of centimetres, while a short ruler may be easier to handle for a small object. A stopwatch may be suitable for timing an event, but the procedure should account for the person starting and stopping it. If the timing is difficult to repeat consistently, consider a method that makes the start and end events easier to identify.
Choose materials that allow the planned method to work. For example, an object should be visible if its position will be read against a scale. A support should hold an apparatus steadily if movement would affect the reading. Include only materials that are needed, and follow the teacher’s instructions for using equipment safely.

3. Choose a method and plan a usable procedure

A method is the general approach to gathering evidence. Direct measurement means reading a quantity from an instrument, such as measuring a length with a ruler. An indirect method uses measurements to determine another quantity using a relationship already taught in the course. Choose the simplest method that can address the question and can be carried out with the available equipment.
A procedure turns the method into clear, ordered actions. State how the apparatus will be arranged, what will be changed, what will be measured, and how each reading will be recorded. Keep other relevant conditions the same when you want to compare trials. These are controlled conditions: features kept unchanged so the comparison is more useful. Give each recorded value its unit, and include direction when needed.
Plan how to make the evidence dependable. Repeat readings when practical and when repetition helps reveal inconsistent results. Decide in advance what you will record and how you will compare the readings. Do not promise that a procedure will produce a particular result. A planned procedure is not a completed investigation, and a proposed reading is not measured evidence.
A computer model or simulation can help explore a situation, but its output is simulated evidence. It is not a physical measurement from laboratory equipment. State clearly whether evidence comes from an actual measurement or from a simulation, and do not describe one as the other.

4. Review the plan before using it

Before beginning, check whether the equipment can answer the question, whether the procedure gives enough detail for another student to follow, and whether the materials and steps are appropriate for the setting. Check that readings can be recorded clearly and that the plan includes relevant units and directions. If a step is unclear, improve it before collecting evidence.
A strong plan is not necessarily complicated. It is a good match between the question and the tools, materials, method, and procedure. When one choice does not fit, revise the plan rather than trying to force unsuitable equipment to work.

Worked example

Planning a distance-and-time investigation

A class wants to investigate how long a small cart takes to travel a marked straight distance. Choose suitable equipment, materials, a method, and a proposed procedure. No measurements have yet been collected.
  1. Identify the evidence needed
    The plan needs a distance and a travel time. Both are scalar quantities, so each reading needs a number and a unit. The question is about elapsed time over a marked route, not the cart’s direction.
  2. Choose the equipment and materials
    A metre stick or tape measure can mark the route, and a stopwatch can time the cart. The cart and a clear, level path are materials or setup items needed for the proposed method. The chosen distance should fit the measuring tool’s range.
  3. Write a repeatable procedure
    Mark a start and finish point. Measure and record the distance in metres. Release the cart at the start and time its travel to the finish. Record the time in seconds, repeat the timing when practical, and use the same release point and route. These are proposed steps, not completed measurements.
Answer: Use a measuring tool suitable for the route length, a stopwatch, a cart, and a clear path. Record distance in metres and time in seconds. Keep the route and release point consistent.
Check: The plan matches the question and identifies units. It makes no claim about a measured travel time.

Worked example

Choosing a method for a small length change

A student plans to compare the length of a spring before and after adding a small load. The expected change is small. Choose suitable equipment and describe how to improve the comparison.
  1. Match scale to the change
    A measuring tool with marks that are too far apart may not show a small length change clearly. Choose a ruler with a suitable scale and a range long enough for the spring’s full length.
  2. Set up a consistent comparison
    Secure the spring vertically beside the ruler and use the same reference point for both readings. Record the initial and final lengths in metres or centimetres, using the same unit throughout. Keep the ruler and reference point in place so the comparison is not affected by moving the scale.
  3. Review the limitations
    The plan should explain how the spring is supported and how the reading is taken. If the marks or spring end are hard to see, revise the setup before collecting readings. Do not claim a length change until it has actually been measured.
Answer: Use a ruler whose scale can show the planned small change and whose range covers the full spring length. Read both lengths from the same reference point and record them using one unit.
Check: The scale and reference point are chosen to make the comparison clearer. The plan distinguishes intended measurements from actual evidence.

Worked example

Deciding whether a simulation fits the question

A group wants to study a circuit but has no access to circuit equipment during planning. They can use a computer simulation. Choose a suitable planning approach and explain what the output can and cannot show.
  1. Match the method to available tools
    A simulation is suitable for exploring a circuit model when physical equipment is unavailable. The group should identify the circuit components and the quantities the simulation displays before choosing what to record.
  2. Plan the comparison
    Change one planned setting at a time and record the displayed values with their units. Keep other settings unchanged for a fair comparison within the model. State that these values are simulation output.
  3. Describe the evidence accurately
    The simulation can provide evidence about the model’s output. It does not provide a reading measured from a physical circuit. If the group later has equipment, a physical investigation would require a separate procedure and actual measurements.
Answer: Use the simulation as a planned method for examining model output. Record settings and displayed values with units, and label the results as simulated rather than experimentally measured.
Check: The evidence is described honestly, and the plan does not claim that a physical circuit was tested.

Common mistakes and how to avoid them

Choosing equipment because it is available, without checking whether its range or scale suits the measurement.
Correction: Compare the instrument’s range and scale with the quantity and size of change you plan to measure.
Writing a vague procedure such as “measure the motion” without stating what to measure or how to record it.
Correction: List the ordered actions and identify each quantity, unit, and direction that must be recorded.
Changing several conditions at once when comparing trials.
Correction: Keep relevant conditions consistent so the planned comparison is easier to interpret.
Reporting a planned reading or simulation output as if it were measured in a laboratory.
Correction: Label each result as proposed, simulated, or actually measured.

Lesson summary

Check your understanding

Question 1

A planned measurement is much smaller than the spacing between the marks on a ruler. What is the best response?
  1. Use the ruler anyway and report extra decimal places.
  2. Choose a measuring tool with a more suitable scale and range.
  3. Record the result without a unit.
  4. Replace the measurement with a simulated value without saying so.
Show answer and explanation
Choose a measuring tool with a more suitable scale and range.
The tool’s scale must suit the measurement. Reporting extra decimal places does not make a coarse scale more precise.

Question 2

Which statement correctly distinguishes a method from a procedure?
  1. A method is the general approach; a procedure is the ordered set of steps.
  2. A method is a measurement unit; a procedure is an instrument.
  3. A method is always a simulation; a procedure is always a physical test.
  4. They mean exactly the same thing.
Show answer and explanation
A method is the general approach; a procedure is the ordered set of steps.
The method describes how evidence will generally be gathered. The procedure gives the steps for carrying it out.

Question 3

A computer model displays a value for a circuit quantity. How should a student describe that value?
  1. As a physical measurement from laboratory equipment.
  2. As a measured result, because the display includes digits.
  3. As simulation output, not a physical measurement.
  4. As a result that needs no units or explanation.
Show answer and explanation
As simulation output, not a physical measurement.
A simulation produces model output. It is not a reading taken from a physical circuit.

Key terms

Quantity
A feature that can be measured or counted, such as length or time.
Scalar
A quantity with size and unit but no direction.
Vector
A quantity with size, unit, and direction.
Range
The span of values an instrument can measure.
Scale
The marks or display increments used to read a measuring instrument.
Precision
How finely an instrument can distinguish readings.
Method
The general approach used to gather evidence.
Procedure
The ordered steps for carrying out a method.

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About this lesson and its review

Published by DoAssignment. This AI-assisted lesson follows Ontario Grade 11 Physics (SPH3U), expectation A1.2. 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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