Year 8 · Questions, explanations and predictions

Learn the idea

A scientific question identifies something that observations or measurements could help answer. State what will be compared and how the outcome will be recognised. A broad word such as best needs a chosen measure before it becomes a useful investigation. Some questions about values or preferences have no single scientific verdict.

Observation, explanation and evidence

An observation records what is noticed or measured. An inference is an explanation drawn from observations, rather than a direct observation itself. Evidence is the observations and measurements used to judge an idea. Keep an original record and separate it from a possible explanation so another person can check the reasoning.

Make a reasoned prediction

A prediction states what you expect before checking the outcome. Add a scientific reason: I expect this change because this process should have that effect. A hypothesis is a proposed explanation that can be tested; a prediction follows from an explanation or model. Neither becomes a recorded result just because it sounds convincing.

Testability has limits

An experiment is one way to gather evidence; careful observations of things that cannot be changed by a learner can also be scientific. A question may be testable in principle but unsuitable or unsafe for a classroom. Use supplied data or simulations here, and revise an explanation when the evidence conflicts with it.

Separate a pattern from its cause

A supplied street survey shows warmer readings at darker-looking surfaces. Colour, material, shade, time and location may all differ. The observed pattern can suggest a question, but it cannot isolate colour as the cause. A stronger virtual comparison keeps material and exposure alike while changing surface colour.

Build a testable explanation

One hypothesis is that a stated darker surface absorbs more of the incident light under the model conditions, producing a greater temperature rise. Predict a measurable temperature change after a stated time. The prediction needs the same starting temperature and exposure to support a useful comparison; it is not a rule about every dark object in all conditions.

Use a prediction model openly

A fictional model starts at 20 °C and predicts an increase of 2 °C each minute over a short stated interval. At three minutes its prediction is 26 °C. This is an output from an assumed rule, not an observed temperature. If the supplied reading differs, retain it and check the rule and conditions rather than calling the model a measurement.

Make the question answerable

Which surface is good? leaves the outcome undefined. How does colour affect temperature rise after five minutes for matched virtual surfaces under equal exposure? sets a measurable question. Whether a surface should be used in a public place also involves values and other evidence, such as accessibility and maintenance, beyond this one temperature comparison.

Common mistake

A darker surface reading in a street survey is not by itself a controlled comparison of colour.

An alternative explanation

If one surface was shaded and another sunlit, exposure could contribute to the difference even when the colours differ.

A model limit

A straight 2 °C-per-minute rule over a short virtual interval does not establish indefinite warming at the same rate.

Your written practice

Show your working on paper and enter your answer here. If it does not match, compare the model and try again.