What a context report has to do
Physics first, context second
A context report is about how deeply you understand the physics, not about how well you describe the context. There are three things the writing can do, and each one demonstrates more than the last.
| What the writing does | What that means you write |
|---|---|
| Describe — give characteristics of, or an account of, the physics related to the context | Correctly describe the relevant physics concepts, using the right terms |
| Explain — give reasons as to how or why the physics applies to the context | Explain the mechanism — why this concept produces this effect here |
| Integrate — link ideas together, and elaborate, justify, relate, evaluate, compare and contrast, or analyse | Connect two or more concepts into one explanation, and use them to justify or evaluate something specific |
The single most important rule
- The report is about the physics, not about the context. A beautifully written description of how an airbag is manufactured does nothing for you; a short paragraph explaining how it increases the time of impact and therefore reduces the force is the actual work.
- Ask of every sentence you write: which physics concept is this sentence about? If the honest answer is "none", it is background, not evidence.
What counts as evidence
- Explanations in your own words, using correct physics terminology.
- Calculations using the physics of the context, with realistic values.
- Diagrams — force diagrams, ray diagrams, circuit diagrams, energy-flow diagrams — properly labelled.
- Your own measurements and observations, where the context allows them (timing a swing, measuring a temperature drop, reading a power rating off an appliance).
- Not evidence: copied text, or a paraphrase that changes the words but shows no sign that you understood them.
Choosing which physics to include
- Include physics that genuinely explains a feature of the context.
- Leave out physics that is correct but irrelevant. A definition of momentum in a report on lens design explains nothing about lenses, and it dilutes the report.
- Two or three concepts explained thoroughly beats six concepts mentioned.
One idea, taken all the way
Take a bicycle helmet as the example.
- Describe: "A helmet contains a layer of polystyrene foam, which is crushable. Impulse is the product of force and the time over which it acts, ."
- Explain how or why: "The foam crushes during an impact, so the head takes longer to come to rest. The change in momentum is fixed by the speed the head was travelling at, and since , spreading the same change in momentum over a longer time means the force on the skull is smaller."
- Integrate and justify: links impulse–momentum with energy: "...the foam also does work as it crushes, converting the head's kinetic energy into deformation of the foam. This is why the foam must be permanently crushable rather than springy: a springy material would return the energy and push the head back, whereas a crushable one absorbs it. Both ideas point to the same design rule and explain why a helmet that has taken one impact must be replaced even if it looks intact."
Worked ExampleRewriting a weak paragraph, one step at a time
A student writing about car braking systems submits this paragraph:
"Cars have anti-lock braking systems (ABS). ABS stops the wheels locking up when you brake hard. This helps the car stop safely and lets the driver steer. Modern cars all have ABS and it is much safer than older systems."
Assess this paragraph and rewrite it until the physics is doing the work.
Step 1 — Assess what is there
The paragraph is accurate and clearly written, but it contains no physics at all. Every sentence describes what the technology does; none explains why it works. A person with no physics knowledge could have written it from a car advertisement.
As it stands there is nothing in it to assess as physics at all. A report has to describe physics concepts, not just the technology they are hiding behind.
Step 2 — Add the physics concepts
Name the relevant physics and define it:
Physics is now present and correct. That is the foundation — and on its own it is still only description.
Step 3 — Give reasons why
Explain how the physics produces the observed behaviour:
The physics now explains the technology instead of sitting alongside it.
Step 4 — Connect the concepts and justify
Bring in a second concept and use both together:
Two concepts — friction and circular motion — are now integrated to explain a single feature, and the explanation is used to justify a real-world consequence. That is what integrating the physics means.