A prototype test supports only the claims that match it. State the conditions, the result and the limit, and your explanation will be accurate and easy to trust.
This lesson is part of the SPM subjects and learning resources section. The building and testing itself is arranged by your school; here we practise writing about what you observed.
What does an honest observation include?
Use four parts: what you tested, how, what happened, and what this does not show. Numbers and units make each part checkable.
Worked example: a carry handle
Here is an original example. A student makes a cardboard carry handle for a box of books. The test: hang a 2 kg load from the handle for 10 seconds, five times.
Observation. In all five trials the handle held the 2 kg load for 10 seconds, with no tearing. After the fifth trial a small crease appeared near one edge.
Overclaim. “The handle is strong and can carry heavy loads.”
Honest explanation. “In five trials with a 2 kg load held for 10 seconds, the handle did not tear, which suggests it can carry 2 kg for short periods. A crease appeared after the fifth trial, so repeated use may weaken it. The test did not use heavier loads or long carrying times, so I cannot say it is suitable for 5 kg or for daily use.”
The mistake that costs marks
Two slips appear together: a word such as “strong” that has no measurement, and a general claim from a specific test.
| Overclaim | What the test supports |
|---|---|
| “Strong” | Held 2 kg with no tearing |
| “Heavy loads” | Only 2 kg was tested |
| “Reliable” | Five trials, with a crease at trial five |
| “Suitable for daily use” | 10-second tests only |
A claim check in three questions
For each claim in your write-up, ask: which test supports this, under what conditions, and how many times did it happen? If you cannot answer, narrow the claim or add a test.
Check yourself
A student tests a plant-watering bottle by turning it upside down over a pot. It released 200 ml in 30 seconds on one trial. The write-up says “the bottle waters plants evenly all day.” Rewrite it honestly.
Answer
The test shows one release of 200 ml in 30 seconds. It does not show an even release, a full day or different plants.
Honest version: “In one trial, the bottle released 200 ml in 30 seconds when turned upside down over a pot. This shows that water flows out when the bottle is turned over. I have not tested it over a full day or repeated the trial, so I cannot say it waters evenly all day.”
What to study next
After a test, you decide what to change. Continue with reflect on an original development decision and then the Invention original practice set.
The structured answer self-review helps you check that each claim has a test behind it. A teacher can read your write-up with you in online one-to-one Invention tuition.