Natural sciences
Matter, measuring and reactions
Educator section
Memorandum
- Organic: living; non-organic: non-living
- Observation: The vinegar reacted with the milk to form a "new" substance with "new" properties
- Conclusion: The special characteristics of milk and vinegar were used to produce a new synthetic material
- Uses of "new" substance: As plug to seal something; protection; decoration, etc.
- As in given illustration, but with the containers used and the heat source (purpose: to practise the learner's ability to represent his/her observation in a sketch).
Leaner section
Content
Activity: to investigate plastic as an example of a synthetic or man-made substance [lo 1.2, lo 1.3]
Plastic is a man-made substance. It was developed because of its special properties and because it is cheaper to manufacture than to find natural materials. Plastic, for instance, is light and waterproof. It is very useful as a packaging material and as protection for other materials.
Experiment: making your own plastic
Although most plastics are manufactured from petroleum, a similar plastic can be produced from milk. Milk contains carbon and can therefore be classified as an organic substance.
- Consult a dictionary to find the meaning of “organic”.
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REQUIREMENTS:
20 ml vinegar;
a cooking pot;
200 ml full-cream milk
METHOD:
- Pour the milk into the pot and slowly heat it to boiling point.
- Add 20 ml vinegar to the milk.
- Keep the pot on the heat and stir the mixture continuously until it becomes rubbery.
- Remove the pot from the heat and allow the mixture to cool down properly.
- Use water to rinse the mixture.
OBSERVATION:
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DEDUCTION:
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- Possible uses for the “new” material:
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- Refer to the verbal description of the experiment and illustrate the experiment by means of a sketch or a diagrammatic representation of the process.
ASSESSMENT
| LO | MARKS | LEVEL | KEY TO LEVEL |
| 1 | Less than 5 | 1 | The sketch/representation is meaningless, presented without observation or deduction |
| 5 – 7(25% – 39%) | 2 | A basic representation reflecting little observation and no deduction | |
| 8 – 13(40% – 69%) | 3 | A satisfactory representation /sketch showing basic observation, but hardly any deduction | |
| 14 – 20(70% – 100%) | 4 | A complete representation with captions showing the experiment and reflecting both observation and deduction |
Assessment
Learning Outcome 1: The learner will be able to act confidently on curiosity about natural phenomena, and to investigate relationships and solve problems in scientific, technological and environmental contexts.
Assessment Standard 1.2: We know this when the learner conducts investigations and collects data: organises and uses apparatus/equipment or sources to gain and record information;
Assessment Standard 1.3: We know this when the learner evaluates data and communicates findings: generalises in terms of relevant aspects and describes how the data support the generalisation.