Year 6 Science: Predictions and further tests
Part of the Year 6 Science working scientifically (years 5-6) chapter. Chapter overview · whole chapter on one page
Predictions and further tests
A prediction is a sensible guess based on evidence. We use patterns in results to predict what might happen next. A prediction is not proof, so we test it.
A further test checks an idea or repeats a result with a new change. It uses the same method as the first test, with one new changed variable.
Key ideas
- A prediction uses evidence and a pattern in the results.
- A prediction is tested; it is not proof.
- A further test changes one variable, and keeps the rest the same.
- Repeat the test to see whether the result happens again.
Method. Use the pattern from the first test.
- Read the evidence. In the first test Towel C had the largest mean, 19 mL.19 mL
- Make the prediction. If the same pattern holds, Towel C would absorb the most again.Towel C
- Write the answer. Towel C
Check. The prediction should be tested, because the amount of water is different. ✓
Method. Add the growth to the height at the start.
- Start from week 5. The bean is 20 cm in week 5.20 cm
- Add the growth. If it grows 4 cm more, the height is 20 + 4.20 + 4 = 24
- Write the answer. 24 cm
Check. The prediction uses the growth as the pattern, and then the next week will test it. ✓
Method. Find the thing that changes in the further test.
- Read the plan. The further test changes the amount of water.amount of water
- Name the variable. So the changed variable is the amount of water.amount of water
- Write the answer. the amount of water
Check. The towel, and the time, stay the same. ✓
Watch out
Watch out: a prediction is an idea to test. If the results do not match it, the prediction was not supported, and we should say so.
Exam tip
Exam tip. Make a prediction using the evidence, and say which pattern in the results you used.
Try it (with your teacher, or a grown-up at home). Put one plant or one bean seed in a dish of damp cotton wool, and predict how many days it takes to start to sprout. Check every day for a week, and write down what you see. Did the result support your prediction?
Exercise 1D Predictions and further tests
Method. Add the growth to the height at the end of week 5.
- Start at week 5. The bean is 20 cm at the end of week 5.20 cm
- Add the growth. Add 4 cm for week 6.20 + 4 = 24
- Write the answer. 24 cm
Check. This is a prediction, so it can be checked next week. ✓
Method. Look at the first test.
- Read the means. Towel C had the largest mean, 19 mL.19 mL
- Predict. So the prediction is that Towel C absorbs the most again.Towel C
- Write the answer. Towel C
Check. A prediction uses the evidence from the first test. ✓
Method. Think about why we can make a prediction.
- Read the idea. A prediction is a sensible guess based on evidence.evidence
- Write the answer. evidence
Check. Evidence is information from earlier tests or observations. ✓
Method. Keep all the other variables the same.
- Read the test. Only the sunlight changes.sunlight
- Name a fixed variable. The type of bean stays the same, so it is fixed.same bean
- Write the answer. Accept any one of: the type of bean, the amount of water, the pot, the number of days.
Check. Any fixed variable keeps the test fair. ✓
Method. Think about how reliable the mean is.
- Think about repeats. More repeats give a more reliable mean, and 3 is the number used in the first test.three repeats
- Choose. So 3 repeats is a good choice.3
- Write the answer. 3
Check. The first test used three repeats for each towel. ✓
Method. Compare the prediction with the results.
- Read the prediction. Tom predicts that Towel B absorbs more.Towel B more
- Compare. The results show Towel A absorbs more, so the results do not support the prediction.does not support
- Write the answer. no
Check. A prediction can be wrong, and then we say so. ✓
Method. Add two weeks of 5 cm growth to the week 5 height.
- Week 6. The bean is 20 + 5 = 25 cm in week 6.25 cm
- Week 7. The bean is 25 + 5 = 30 cm in week 7.30 cm
- Write the answer. 30 cm
Check. Two weeks of 5 cm each is 10 cm, and 20 + 10 = 30. ✓
Method. Find the thing that changes on purpose.
- Read the plan. The further test changes the size of the towel on purpose.size of the towel
- Write the variable. So the changed variable is the size of the towel.size of the towel
- Write the answer. size of the towel
Check. The water and the type of towel stay the same. ✓
Method. Find what Ruby wants to change.
- Read her idea. Ruby wants to change the temperature of the water.temperature
- Write the variable. So the changed variable is the temperature of the water.temperature of the water
- Write the answer. temperature of the water
Check. The amount of water and the towel must be kept the same. ✓
Method. Think about comparing results.
- Think about the method. If the method changes, the results cannot be compared fairly.cannot be compared
- Think about the change. The same method means only the changed variable can cause a difference.one cause
- Write the answer. Accept any sentence that says using the same method means any difference in the results is caused by the changed variable.
Check. A fair comparison needs the same method each time. ✓
Method. Think about what a prediction is.
- Think about the word. A prediction is a sensible guess that must be tested.guess
- Decide. Only evidence from tests can support an idea, so Ali is not right.no
- Write the answer. Accept any answer that says no, because a prediction is an idea to test, and only evidence from tests can support it.
Check. Test the prediction, then decide whether the evidence supports it. ✓
Method. Think about what plants need.
- Think about water. Plants need water to make their cells and grow.water
- Make the prediction. So without water, the growth would stop or slow down.stop or slow
- Write the answer. Accept any answer that says the growth would stop or slow, because plants need water to grow.
Check. This prediction could be tested by keeping one plant without water. ✓