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GOOD DATA STARTS WITH A GOOD QUESTION

Published: Sep-2026 | Category: General

Collecting data is easy. Making it useful is the tricky part.

Before you pick up a sensor, start with one simple question: What am I actually trying to find out?

That question shapes everything that follows. It helps you decide what to measure, which sensor to use, how often to take a reading, how long to collect data and how best to present the results.

Get those first decisions right and it becomes much easier to spot patterns, investigate unusual results and reach a conclusion supported by evidence.

Start with a clear question

A useful scientific question tells you which variables matter and how they are related. For example:

How does the temperature of water change as it cools?

This question shows that temperature must be measured over time. It also suggests that a line graph will be helpful because the aim is to see how a measurement changes continuously.

Before collecting any readings, ask:

  • What am I changing or observing?
  • What am I measuring?
  • How often should I take a reading?
  • How long should I collect data for?
  • Which conditions need to stay the same?

Choose the right sensor

Once the question is clear, choose a sensor that suits the measurement. Check five things before you begin:

  • Suitability: Is the sensor designed to measure what you need?
  • Range: Can it measure the values you expect?
  • Sampling: How often should it record a value?
  • Position: Is it placed correctly and consistently?
  • Conditions: Are the other conditions kept consistent?

For cooling water, a Wireless Temperature Sensor should remain in a consistent position in the water throughout the investigation. Changing its depth or letting it touch the container could affect the measurements and make comparisons less reliable.

Choose the right display

The best display depends on what you need to see. EasySense offers several ways to view data:

  • Dial Meter: useful for watching a measurement change.
  • Number Display: useful when you need an exact current value.
  • Table: useful for comparing a series of individual readings.
  • Graph: useful for seeing a relationship or pattern in the data.

You can move between displays as the investigation develops. A number display may help while setting up the apparatus, while a graph may make the overall pattern much clearer once readings have been collected.

Record numbers with their units

A number on its own is incomplete. A useful measurement needs a value and the correct unit, such as:

  • Temperature = 21.4 °C
  • Time = 30 s
  • Distance = 2.5 m

Data Harvest loggers report the units selected for the connected device. Take extra care to check the units when using calculated values or Snapshot data.

Use the graph that fits the question

A graph is only useful if it matches the type of data being presented.

Use a bar chart when comparing separate groups or categories, such as the temperature measured in four different rooms.

Use a line graph when showing how a measurement changes continuously, such as the temperature of water as it cools. Time normally goes on the x-axis and the measured variable on the y-axis.

Whichever graph you choose, make it easy to understand:

  • label both axes;
  • include the correct units;
  • use equal intervals and a sensible scale;
  • add a clear, descriptive title.

A good scale uses the available space and makes meaningful differences visible. Large measurements might use intervals of 10, while smaller measurements might need intervals of 0.2.

Look carefully at what the data is telling you

You do not need complicated analysis to get started. Begin with straightforward questions:

  • What is the highest value?
  • What is the lowest value?
  • What is the difference between them?
  • Is the result increasing, decreasing or staying steady?
  • Is there a pattern or trend?
  • Is there an unusual result worth investigating?

For example, the temperature readings 18.2, 18.7, 19.1, 20.0 and 21.3 °C show an increasing trend. That is a useful first observation, but the next step is to consider why the increase happened and whether the evidence answers the original question.

Do not automatically remove a reading simply because it looks unusual. Check the apparatus, sensor position and conditions first. An unexpected result may be an error, but it may also reveal something worth exploring.

Summarise the results

Simple statistics can make a set of measurements easier to describe:

  • Mean: the average value.
  • Minimum: the lowest value.
  • Maximum: the highest value.
  • Range: the difference between the highest and lowest values.
  • Standard deviation: an indication of how spread out the measurements are.

When two variables show a relationship, a Least Squares Fit can add a best-fit line to the data. This helps describe the overall trend, judge how closely the points follow it and make careful predictions within the measured range.

Check before drawing a conclusion

Before finishing, work through a quick check:

  • Are the numbers accurate and shown with the correct units?
  • Does the display or graph suit the type of data?
  • Are the axes labelled and is the scale sensible?
  • Does the graph have a clear title?
  • Have appropriate statistics been used?
  • Can the main pattern be described clearly?
  • Does the evidence answer the original question?

Follow the data journey

Question → Sensor → Data → Graph → Analysis → Conclusion

Good data does not begin with pressing record. It begins with a clear question and a sensible plan. Choose the right sensor, collect measurements consistently and present them in a way that makes the pattern easy to see.

Better measurements. Clearer data. Better conclusions.

Download the full activity

The Data Presentation: Practical Advice guide provides a classroom-ready summary of choosing sensors and displays, using units, selecting graphs, setting scales and analysing results.

Find and download the worksheet in Practical Explorer

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