Lesson focus: A results table should allow another scientist to check exactly what was measured.
Record raw dataThe measurements you write down during an experiment, before you do any calculations. with headingThe label at the top of a table column, saying what was measured and its unit, such as "Time (s)"., units, consistent precisionHow finely a measurement is given, for example 12.4 cm is more precise than 12 cm. and space for repeats.
Build on earlier learning
Laboratory equipmentRevisit units, resolution and sensible precision before recording raw data.
You will be successful when you can…
- Construct headings in the form quantity / unit.
- Place the independent variable in the first column.
- Separate raw measurements from calculated values.
- Record consistent precision without altering unexpected values.
Words that carry the science
- raw data
- Measurements or observations recorded before calculation.
- processed data
- Values calculated or transformed from raw data.
- heading
- A label naming the quantity and, where relevant, its unit.
- precision
- How finely a measurement is expressed, linked to scale or resolution.
- anomalous result
- A value that differs unexpectedly from the overall pattern or repeats.
Record data so it can be checked
01Build the structure first
Place the independent variableThe one thing you choose to change in an investigation. in the first column. Use headingThe label at the top of a table column, saying what was measured and its unit, such as "Time (s)". such as “temperature / °C” and “time / s”, so each cell contains a number rather than a repeated unit.
Give every repeated raw dataThe measurements you write down during an experiment, before you do any calculations. its own column. Put calculated processed dataValues worked out from raw data, such as a mean or a percentage., such as a mean, in a separate labelled column.
02Preserve what was measured
Record values immediately and to precisionHow finely a measurement is given, for example 12.4 cm is more precise than 12 cm. supported by the apparatus. Measurements from the same instrument are usually recorded consistently.
Do not erase an anomalous resultA result that does not fit the pattern of the others, like one runner's time being far slower than everyone else's. because it looks inconvenient. Retain it, check for a reason and repeat if the plan allows.
03Use categories clearly
Qualitative observations need defined categories or precise descriptions. “Lots” and “a little” are hard to compare unless a scale is defined.
Table titles can state the investigation context, while column headings carry the measured quantities and units.
Keep the evidence trail visible from measurement to calculation.
- Raw repeat 1Recorded directly; never replaced by the mean.
- Raw repeat 2Shows whether the outcome varies.
- Raw repeat 3May reveal an unusual value requiring investigation.
- MeanProcessed summary; calculation and exclusions must be transparent.
Results table and line of best fit
Each reading adds a weight (1 N) to the spring. The table has the independent variable in the first column and units in the headings; the graph gets a line of best fit once there are three points.
Controls
Readings are illustrative. The points scatter a little either side of the line: that is random error.
| Force / N | Extension / cm |
|---|---|
| 1 | 2.7 |
Repair the headings
A table has columns “Temp”, “18 seconds”, “20 seconds”, “19 seconds” and “Average”.
- Rename “Temp” as “temperature / °C”.
- Create repeat columns: “time trial 1 / s”, “time trial 2 / s”, “time trial 3 / s”.
- Move 18, 20 and 19 into one row for the relevant temperature.
- Label the final column “mean time / s”.
How to make the reasoning visible: Headings name quantities and units; cells hold the values.
Temperature and dissolving data
Inspect the table, calculate the means and keep any unusual raw value visible.
| Temperature / °C | Time 1 / s | Time 2 / s | Time 3 / s | Mean time / s |
|---|---|---|---|---|
| 20 | 94 | 92 | 93 | 93 |
| 30 | 73 | 75 | 74 | 74 |
| 40 | 58 | 82 | 57 | 65.7 |
| 50 | 45 | 44 | 46 | 45 |
Look at the 40 °C row. Which result looks odd (anomalous resultA result that does not fit the pattern of the others, like one runner's time being far slower than everyone else's.)?
Why should you keep 82 s in the table, even if you do that test again?
Recalculate the mean for 40 °C without the anomalous 82 s result.
Check your understanding
Answer from memory, then check against the suggested answer.
Which column does the independent variable go in?
Where do you write the unit?
What is processed data?
What is raw data?
What is an anomalous result?
You measure a plant’s height in millimetres every two days. Write the two column headings.
Why does writing every value to two decimal places not make the results more accurate?
Why is it useful to write the units in the column heading instead of after every number?
Exam Question Practice
Exam Question Practice
Mark points shown after marking
You measure the extension of a spring (how much it stretches, in mm) at each force (in N). You do three repeats and work out a mean. Construct the column headings for your results table.
(4)Total for this question: 4 marks
Command word: For constructA command word: draw or build something, such as a table or graph, using the correct layout., write the actual headings, not a description of them.