Years 5 and 6 science · Key Stage 2 · Working scientifically

Years 5 and 6 working scientifically: planning and evidence

Working scientifically is the part of primary science about how scientists find things out. In Years 5 and 6, children plan their own enquiries and choose the right type, control variables, take careful repeat measurements, record data in tables and graphs, draw conclusions that link cause and effect, and judge how far results can be trusted. It is taught through other topics, such as forces or living things, not as a separate unit.

Working scientifically, explained

By Year 5, children are expected to take much more responsibility for the planning than in earlier years. They choose which type of enquiry will answer a question. That might be observing something over time, looking for a pattern, grouping and classifying, carrying out a comparative or fair test, or using books and other sources when the question cannot be tested directly. They explain what must be controlled and why. In a fair test, the thing that is changed is sometimes called the independent variable, and the thing that is measured is the dependent variable. Everything else that could affect the result is kept the same: these are the control variables.

Measuring becomes more careful. Children choose equipment, such as a stopwatch, a newton meter, a thermometer, a measuring cylinder or a data logger, and explain how to use it accurately. They take repeat readings when it matters, for example timing a fall three times, so that one odd result stands out and a typical value (the mean, introduced in maths in Year 6) can be found. They also begin to think about precision: a ruler marked in millimetres gives more detail than one marked in centimetres.

Results are recorded in tables and presented in the form that suits the data: bar graphs for categories, line graphs for measurements that change continuously, such as temperature over time, and scatter graphs when looking for a link between two measurements, such as height and arm span. Keys and labelled scientific diagrams are also used. Children then write or talk about their conclusions. A good conclusion says what the results show, uses the words “because” or “so” to give a causal explanation, and does not claim more than the evidence supports.

The last strand is judging evidence. Children think about how far to trust a result: were there enough repeats, were measurements accurate, was the test fair? They use the results to make predictions and to plan a further test. They also begin to separate fact from opinion in sources and to identify evidence that supports or disproves an idea. Teachers often connect this to the way scientific ideas have changed over time as new evidence was found.

Words your child will hear

Variable: Something that can change in an investigation, such as the size of a parachute or the temperature of water.
Independent and dependent variable: The one thing you change, and the thing you measure to see its effect.
Control variables: The things you keep the same so that the test is fair.
Repeat readings: Measuring the same thing more than once to check the results are reliable.
Scatter graph: A graph of points that shows whether two measurements are linked.
Conclusion: A summary of what the results show and why, using the evidence.
Evidence: Observations and measurements that support or disprove an idea.

What the National Curriculum says

In Years 5 and 6, pupils should be taught to:

Plan different types of scientific enquiries to answer questions, including recognising and controlling variables where necessary
Take measurements, using a range of scientific equipment, with increasing accuracy and precision, taking repeat readings when appropriate
Record data and results of increasing complexity using scientific diagrams and labels, classification keys, tables, scatter graphs, bar and line graphs
Use test results to make predictions to set up further comparative and fair tests
Report and present findings from enquiries, including conclusions, causal relationships and explanations of and a degree of trust in results, in oral and written forms such as displays and other presentations
Identify scientific evidence that has been used to support or refute ideas or arguments

Objectives from the National Curriculum in England, © Crown copyright, used under the Open Government Licence v3.0.

Try it: investigating parachutes

A child asks: does the size of a parachute canopy change how long it takes to fall? Plan the test, handle the results and write a conclusion.

Plan. Change the size of the canopy: squares of plastic bag with sides 10 cm, 20 cm, 30 cm and 40 cm. Measure the fall time with a stopwatch. Keep the same: the material, the string length, the load (for example one small washer) and the drop height.
Predict, with a reason. “The bigger the canopy, the longer it takes to fall, because it catches more air.”

Measure each parachute three times from the same height and record the times. Three readings let you spot a result that does not fit and take a typical value, the mean (add the three, then divide by 3).

Fall time in seconds (s)
Size   1st  2nd  3rd  Mean
10 cm  1.1  1.0  1.2  1.1
20 cm  1.6  1.7  1.5  1.6
30 cm  2.3  2.1  2.2  2.2
40 cm  2.6  2.8  2.7  2.7

10 cm: 1.1 + 1.0 + 1.2 = 3.3
       3.3 ÷ 3 = 1.1

Present. Plot canopy size on the bottom axis and mean fall time up the side. A line graph or scatter graph shows the pattern, because both are measurements, not categories.
Conclude and evaluate. The bigger the canopy, the longer the fall, because a bigger canopy pushes against more air, so there is more air resistance slowing it down. The repeat readings were close together, which gives some trust in the results. But reaction time on the stopwatch affects every reading, and only one material was tested. A further test could use 50 cm and 60 cm squares to see if the pattern continues.

Larger canopies took longer to fall: 1.1 s, 1.6 s, 2.2 s and 2.7 s. The results support the prediction that a bigger canopy catches more air and slows the fall, with reasonable trust because the repeats agreed.

Common mistakes and how to help

Thinking an investigation is only a fair test

Fair tests are the best-known practical work, so children use them for every question, even ones such as “How do shadows change in the day?” that need observing over time.

What helps: Before starting, ask “What type of enquiry fits best: observing, spotting a pattern, grouping, a fair test or research?” and ask your child to explain why.

Treating one result as the answer

A single result feels complete, and repeating it can seem like a waste of time or an admission that the first go was wrong.

What helps: Make a game of it: do the same simple test three times (roll a car down a ramp) and see how much the results differ. Ask which result you would trust and why.

Confusing the independent and dependent variables, or controlling the wrong thing

The words sound alike. Children also find it hard to list everything that could change a result, and often control one thing but miss another.

What helps: Use plain phrases at home: “what we change”, “what we measure” and “what we keep the same”. Then, before testing, ask “What else could change the result?”.

Drawing a conclusion that the data can’t support

Children want a tidy story. They may say “this proves…” after one small test, or claim one thing causes another when the data only show that the two go together.

What helps: Ask “How do you know?” and “What would make you more sure?”. Practise phrases such as “the results suggest” and “this was only tested with…”.

How to help at home

Turn everyday questions into investigations. When your child wonders something, such as which surface a ball bounces highest on, ask them to plan it. What will they change, what will they measure, and what will they keep the same? Even if you don’t run the test, planning it is the key skill.
Repeat and compare. Time how long it takes an ice cube to melt in a cup of room-temperature water, or how long a paper helicopter takes to fall from the same height, three times. Work out the typical time together.
Draw the right graph. Record a week of outdoor temperatures at the same time each day and draw a line graph. Or measure family members’ height and hand span and plot a scatter graph. Ask what the graph shows and what it does not.
Spot fact and opinion. Read a short news item or product claim together. Which parts are evidence, which are opinion, and what extra evidence would you want to see?

Builds on

Years 3 and 4: Fair tests and enquiries
Years 3 and 4: Results and conclusions

Leads on to

Key Stage 3: Scientific attitudes
Key Stage 3: Planning science investigations
Key Stage 3: Analysing and evaluating data
Key Stage 3: Units, equations and calculations

Everything in Years 5 and 6 science

Updated 20 October 2026.