A valid conclusion is supported by results from a fair test. It describes the relationship, quotes data, and explains it using science ideas: 'As the temperature of the acid increased, the reaction time decreased, from 80 s at 20 °C to 20 s at 60 °C, because particles move faster and collide more often.'
Avoid over-claiming. Results from five temperatures cannot prove what happens at 100 °C. Words like 'always' and 'proves' are rarely justified; 'suggests' and 'supports' are more honest. If the data are spread out or there are anomalies, say so.
Worked example
A test of three plant foods found food B gave the tallest plants. Is 'Food B is the best plant food in the world' a valid conclusion?
- Only three foods and one kind of plant were tested.
- The result cannot be applied to all foods and plants.
Answer:No: 'Food B gave the tallest plants in our test' is valid.
Key words
- valid
- based on a fair test that answers the question
- over-claim
- say more than the evidence shows
- suggests
- shows evidence for, but not proof
- explain
- give a scientific reason
New questions every time.