Once you know the pattern, you can predict results you did not measure. If the car rolled 120 cm from a 20 cm ramp and 180 cm from a 30 cm ramp, then a 25 cm ramp should give a distance between 120 cm and 180 cm, probably about 150 cm.
Predictions are best between values you measured. Predicting far beyond your results is risky, because the pattern might change; a very steep ramp might make the car crash instead of rolling further. You can test a prediction by doing the experiment and checking whether you were close.
Worked example
Cress grew 14 mm with 2 hours of light and 24 mm with 4 hours. Predict the height for 3 hours.
- 3 hours is halfway between 2 and 4 hours.
- The height should be between 14 mm and 24 mm.
Answer:About 19 mm, halfway between.
Key words
- predict
- say what you think will happen, using evidence
- between
- in the gap from one value to another
- estimate
- a sensible guess using evidence
- check
- test whether a prediction was right
Practise this
New questions every time.