Science tuition for Yishun families should help students distinguish the values an investigation actually records from the values later calculated from those observations. This matters because a difference, percentage, average or rate can be useful without being a direct measurement.
This rebuilt legacy URL now owns one distinct Science data-literacy job: raw observation → recorded value → derived calculation → unit check → evidence statement → claim. Old generic promotional copy and stale Yishun-centre wording have been removed.
eduKateSG does not claim a current Yishun branch. Current centres are at 83 Punggol Central, Singapore 828761 and 8 Fourth Avenue, Singapore 268674. Selected Primary Science classes run in focused 3-pax small groups, typically 1.5 hours.
The Direct Answer
Raw data is what was directly observed or measured.
Derived data is calculated from raw data.
Example:
Raw: starting temperature = 70°C; final temperature = 52°C.
Derived: temperature decrease = 18°C.
Always know which numbers came from the instrument and which came from your calculation.
Worked Example: Plant Growth
Raw measurements:
- Day 1 height = 8 cm;
- Day 7 height = 14 cm.
Derived value:
growth = 14 − 8 = 6 cm.
If the question asks how much the plant grew, the derived value is the relevant answer.
Worked Example: Cooling
Raw:
- 0 min = 70°C;
- 5 min = 60°C;
- 10 min = 54°C.
Derived:
- first interval decrease = 10°C;
- second interval decrease = 6°C;
- total decrease = 16°C.
The raw readings remain unchanged even when several useful calculations are derived from them.
Worked Example: Rate
Raw:
water volume falls by 12 mL over 4 hours.
Derived average rate:
12 ÷ 4 = 3 mL/hour.
The instrument did not directly display “3 mL/hour”; the student calculated it.
Worked Example: Percentage
Raw:
18 seeds germinated out of 20.
Derived:
18/20 = 90%.
The percentage summarises the raw count relative to the total.
Worked Example: Average
Raw trial times:
20 s, 22 s, 21 s.
Derived mean:
(20 + 22 + 21) ÷ 3 = 21 s.
The average is a useful summary, but the raw trials should still be available because variation matters.
Why Raw Data Matters
If the student keeps only the average, they can no longer see whether one trial was unusual.
Raw values preserve the evidence history.
Why Derived Data Matters
Derived values answer questions that raw readings alone may not answer directly:
- how much changed?
- how fast?
- what proportion?
- what average?
- what difference between groups?
The Provenance Question
Ask of every number:
Where did this value come from?
- instrument reading?
- count?
- calculation?
- graph estimate?
This prevents students from treating all numbers as equally direct evidence.
Measured vs Calculated Units
Raw temperature: °C.
Temperature difference: °C.
Rate of temperature change: °C/min.
Derived quantities may require new compound units.
Worked Example: Absorbency
Raw:
sample mass before = 10 g.
sample mass after = 18 g.
Derived water absorbed = 8 g.
If comparing unequal sample sizes, another derived value such as absorbed amount per gram may be needed.
Raw Data Should Not Be “Cleaned” Silently
If one trial looks unusual, do not erase or replace it simply because it does not fit the expected pattern.
Record it, investigate the method, and explain any justified decision about whether to repeat or exclude it.
Derived Data Can Hide Variation
Two groups may have the same average but very different raw values.
Group A: 10, 10, 10.
Group B: 5, 10, 15.
Both average 10, but Group B varies much more.
At Primary level, students need not perform advanced statistics; they should simply recognise that an average can hide the spread of raw results.
Rounded Values
If a derived calculation produces a long decimal, follow the precision appropriate to the task and the raw measurements.
Do not imply more precision than the original instrument supported.
Graph-Read Values
A value read approximately from a graph is not the same as an exact raw instrument reading unless the graph plots the exact original data and the point can be recovered precisely.
Label approximate readings appropriately.
The Raw/Derived Table
| Value | Type | Source |
|---|---|---|
| 14 cm final height | Raw | Ruler measurement |
| 6 cm growth | Derived | 14 − 8 |
| 90% germination | Derived | 18/20 |
| 52°C | Raw | Thermometer reading |
The Reverse Calculation Check
If growth = 6 cm and initial height = 8 cm, final height should be 14 cm.
Reverse-checking derived values can catch arithmetic errors.
The Sign Check
Final − initial can be positive or negative.
70°C → 52°C gives −18°C if signed change is used, or an 18°C decrease in ordinary school language.
Be explicit about direction.
Raw Data vs Claim
Raw:
Plant A = 14 cm; Plant B = 11 cm after seven days.
Derived difference:
A is 3 cm taller at Day 7.
Claim:
“Plant A was taller than Plant B after seven days under the tested conditions.”
Do not jump from one derived value to an unrelated universal claim.
Calculation Is Not Explanation
Finding that A cooled 6°C more than B tells us what differed.
Explaining why requires the relevant Science mechanism and experimental conditions.
Data Workflow
- observe/measure;
- record raw data;
- check units;
- calculate only what the question needs;
- label the derived quantity;
- compare;
- explain if required;
- state the evidence boundary.
Primary Science Context
MOE’s Primary Science syllabus integrates measurement, data processing, comparison and evidence communication across P3–P6. Distinguishing raw from derived values supports tables, graphs and investigations. Official reference: MOE Primary Science Syllabus.
Common Raw/Derived Data Failure Modes
| Symptom | Issue | Repair |
|---|---|---|
| Growth treated as direct ruler reading | Derived value misunderstood | Show subtraction |
| Average replaces raw trials | Variation hidden | Keep raw values |
| Compound unit missing | Derived rate unclear | Add per-time unit |
| Outlier silently deleted | Evidence record altered | Record and investigate |
| Calculation used as cause | Description/explanation mixed | Add mechanism separately |
Why Three Students Helps
One student identifies raw values, one calculates the derived quantity and the third audits the unit, arithmetic and whether the final claim goes beyond either.
When Yishun Families May Consider This Support
- The child confuses final value with change.
- Rates and percentages are calculated without understanding their source.
- Averages replace the original trial data.
- Data calculations are correct but conclusions overreach.
What Progress Should Look Like
A stronger learner can trace every value back to its source, distinguish direct observation from calculation, preserve units and use derived data as evidence without confusing calculation with scientific explanation.
Independent location notice: eduKateSG does not claim a current Yishun branch. Current centres: 83 Punggol Central, Singapore 828761 and 8 Fourth Avenue, Singapore 268674. Contact +65 8823 1234.