Models and Representations
Section: Thinking and Working Scientifically | Syllabus: Cambridge Primary Stage 5 Science (0097)
What Is a Scientific Model?
- A scientific model presents an object, process or idea in a way that shows some of its important features.
- A model can be a diagram, a physical object, a sequence of stages, a table or a computer animation.
- Models are useful because some things are too large, too small, too slow, too fast, too dangerous or too hidden to observe directly
- a globe and lamp model the Earth and Sun without needing to travel into space
- a particle diagram models something far too small to see, even with a microscope
- A model is never a perfect copy of the real thing
- it leaves out details that are not needed for the explanation
- its limits should always be remembered when using it as evidence
Models can take many forms, from particle diagrams to physical objects
Using Diagrams to Explain Science
- Give a diagram a clear title and use simple, neat labels.
- Use arrows to show movement, direction or the order of a sequence.
- Explain what each part of the model represents and what the model helps the reader understand.
| Model | Useful for | Limit |
|---|---|---|
| Particle diagram | Showing particle spacing and arrangement | Particles are not really coloured circles |
| Water-cycle diagram | Showing a repeating process | Distances and times are not to scale |
| Globe and lamp | Showing Earth, sunlight and seasons | Sizes and distances are greatly simplified |
Question: A learner wants to explain why water droplets form on the cool lid of a container. Which model would be most useful, and what should it show? [2]
The explanation concerns particles changing from a gas to a liquid. Choose a particle diagram and show gas particles losing energy and becoming closer together. AnswerUse a particle model. It should show water-vapour particles cooling, losing energy and moving closer together to form liquid droplets.
Common Mistakes
MistakeA model must include every detail of the real object.
FixA useful model highlights the features needed for the explanation and may leave other details out.
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