Working scientifically
By the end of this chapter you will be able to
- Ask questions that I can test, and say which type of enquiry would answer them
- Plan a fair test: change one thing, measure the result, and keep everything else the same
- Take careful observations and accurate measurements, using standard units
- Record, sort and present my results in a table, a key, a bar chart or a labelled diagram
- Write a report, a conclusion and a prediction that match my results, and suggest an improvement
- Compare differences and similarities, and say which evidence supports an idea
You should already know
- Asking simple questions and making a fair test (Year 2 Science, Chapter 1)
- Measuring with a ruler and reading scales, and reading simple tables and bar charts (Year 2 Maths and Science)
Where this leads
- Planning fair tests and using evidence in the plant and light chapters of this book (Chapters 2 to 8)
- Using a range of enquiries and more precise measurements in Year 4 Working scientifically
National Curriculum for England, Key Stage 2 science, Year 3. Content: WS1 ask relevant questions and use different types of scientific enquiries to answer them, WS2 set up simple practical enquiries, comparative and fair tests, WS3 make systematic and careful observations and take accurate measurements using standard units, with thermometers and data loggers, WS4 gather, record, classify and present data in a variety of ways, WS5 record findings using simple scientific language, drawings, labelled diagrams, keys, bar charts and tables, WS6 report on findings, with oral and written explanations, displays and conclusions, WS7 use results to draw simple conclusions, make predictions for new values, suggest improvements and raise further questions, WS8 identify differences, similarities or changes related to simple scientific ideas and processes, WS9 use straightforward scientific evidence to answer questions or to support findings.
Exercise P Do you remember?
Method. Think about what each tool is for.
- Think about the job. We want to measure a length, not a time.length
- Choose the tool. A ruler measures length in centimetres.ruler: length
- Write the answer. ruler
Check. A timer measures time, so it is not the answer. ✓
Watch out. A ruler measures length. A timer measures time.
Method. A fair test changes only one thing.
- Count the things that change. Two things change: the cup and the water.cup and water change
- Decide whether it is fair. Only one thing should change in a fair test.two changes: not fair
- Write the answer. no
Check. Change only the cup, or only the water, and the test would be fair. ✓
Method. Count the groups of five first. Then count the marks left over.
- Count the full groups of five. Each full group has five marks.2 groups = 10 marks
- Count the marks left over. These marks are not in a full group.3 marks left
- Add them together. 10 and 3 make 13.10 + 3 = 13
- Write the answer. 13
Check. Count every mark one at a time, and you also get 13. ✓
Watch out. Count the groups of five first, then the single marks.
Method. Look at the units. Find the measurement that is not a length.
- Look at the units. Three of the measurements are lengths, in centimetres.3 cm, 7 cm, 9 cm
- Find the one that is different. Kilograms measure mass, not length.2 kg is a mass
- Write the answer. 2 kg
Check. The other three are all lengths in cm. ✓
Method. Think about which tool counts seconds and minutes.
- Think about the job. We want a tool for time, not for length or temperature.time
- Choose the tool. A timer counts how long something takes.timer: time
- Write the answer. timer
Check. A thermometer measures temperature, so it is not the answer. ✓
Asking relevant questions
A relevant question is one about the thing we are studying. We can answer it with evidence: facts that we have measured, observed or read in a reliable source.
“Is the field the best place to play?” is an opinion. People can disagree about it, so it is not a science question.
Scientists answer questions in different ways. These are the types of enquiry that you will meet in this book:
| Type of enquiry | What we do | Example question |
|---|---|---|
| Comparative and fair test | change one thing, measure the result and compare the results | Which paper towel soaks up the most water? |
| Observing over time (practice only) | look at the same thing again and again, and record what changes | How much water is left in a jar each day? |
| Pattern seeking (practice only) | look at the results and find what goes together | Do taller stacks of books have more books? |
| Secondary sources (practice only) | use a book or a reliable website, with a grown-up, to find facts that others have recorded | What do pandas eat? |
Practice only: observing over time, pattern seeking and secondary sources are practice for this chapter. They are not separate statements, but they help you use the enquiry skills in the rest of the chapter.
Key ideas
- A relevant question is about the thing we are studying, and we can find its answer with evidence.
- An opinion, such as “Which is the best?”, is not a science question.
- A comparative test compares results for different things. A fair test changes only one thing.
- Observing over time, pattern seeking and secondary sources are practice only.
Method. Look for a question that we can test by comparing results.
- Is it about what we are studying? It is about paper towels and water, so it is relevant.paper towels and water
- Can we test it? We can use the same water on each towel and compare the results.compare the towels
- Choose the type of enquiry. We compare different towels in a test, so it is a comparative test.comparing towels
- Write the answer. comparative and fair test
Check. We change the towel and measure the water. ✓
Watch out. A comparative test compares different things. A fair test changes only one thing.
Method. Look for the word that asks for a personal view.
- Look for the word best. Best is what someone likes, so the question asks for an opinion.best = opinion
- Ask if a test can give one answer. People disagree about the best place, so no test gives one answer.no single answer
- Write the answer. No, it is an opinion
Check. An opinion is not a science question. ✓
Method. Look for words that ask about change over time.
- Look at the words each day. The question asks what happens again and again, over time.each day, this week
- Match it to an enquiry type. We look at the same jar many times and record the change. This is practice only.same jar, many days
- Write the answer. observing over time (practice only)
Check. We look at the same jar again and again. ✓
Watch out
Watch out: a question can be relevant and still be hard to test. Ask yourself: can we measure, observe or find a reliable source that gives the answer?
Try it at home or school (with a grown-up). Go for a short walk outside, or look out of a window. Each of you writes one question about something you see. Choose one question that you can answer with evidence. Say which type of enquiry would answer it.
Exam tip
Grown-up tip. When your child asks a question, ask: “Can we find out by testing, measuring or looking?” Help them decide if it is an opinion or a question we can answer.
Exercise 1A Relevant questions and types of enquiry
Method. Find the question that asks for a length.
- Read question A. It asks for an opinion, so a ruler cannot answer it.A: opinion
- Read question B. It asks for a length, and a ruler measures length.B: length
- Write the answer. B
Check. Measure the leaf and you have the answer. ✓
Method. Decide whether the question can be answered with evidence.
- Read the question. It asks which colour someone likes.likes a colour
- Decide. A personal choice is an opinion, not a science question.opinion
- Write the answer. no
Check. Two people can give different answers. ✓
Method. Think about what we do to find the answer.
- Find the things we compare. We compare three different towels.three towels
- Name the enquiry. Comparing results for different things, with one thing changed, is a comparative and fair test.comparative and fair test
- Write the answer. comparative and fair test
Check. The towels are compared in the same way. ✓
Method. Look for a word that asks for a personal view.
- Look at the word better. Better is a personal judgement.better = opinion
- Decide. We cannot test which animal is better with evidence.opinion
- Write the answer. opinion
Check. People can disagree about this, so it is an opinion. ✓
Method. Look for the same thing being checked again and again.
- Look for repeated checks. The same jar is checked each day.each day
- Name the enquiry. Recording a change again and again over time is observing over time. This is practice only.observing over time
- Write the answer. observing over time (practice only)
Check. We record the same jar on several days. ✓
Method. Look for two things that are compared.
- Read the question. Two balls are compared in the same test.two balls
- Name the enquiry. This compares two things, so it is a comparative and fair test.comparing
- Write the answer. comparative and fair test
Check. Two balls are compared. ✓
Method. Look for a question about a fact.
- Read the question. It asks for a fact that someone else has recorded.a fact
- Name the enquiry. Finding facts in a book or a reliable website is a secondary source. This is practice only.book or website
- Write the answer. secondary source (practice only)
Check. Facts are looked up, not measured here. ✓
Method. Look for a question about what goes together.
- Read the question. It asks whether two things go together.taller and more books
- Name the enquiry. Looking across results for things that go together is pattern seeking. This is practice only.pattern
- Write the answer. pattern seeking (practice only)
Check. We look for a pattern across the stacks. ✓
Method. A relevant question is about the water, and we can answer it with evidence.
- Choose the thing to study. We study the water in the jar.water in a jar
- Check we can answer it. We can measure the water with a measuring cylinder.measure with a cylinder
- Write the answer. Accept any relevant question about the water in a jar that can be answered by measuring or observing, such as “How much water is left after one day?”
Check. Measure the water after one day to answer the question. ✓
Method. Look for the question that is not about how the plant grows.
- Read question A. It asks about height, which we can measure.A: height
- Read question B. It asks for a personal view, so it is an opinion.B: opinion
- Write the answer. B
Check. Only question A can be answered by measuring. ✓
Method. Think about whether counting gives the answer.
- Think about the question. It asks for a number of things.a number
- Decide. We can count the books, so counting gives the answer.count the books
- Write the answer. yes
Check. Counting each book once gives the answer. ✓
Method. Think about what the question asks us to look for.
- Find the key idea. She wants to know whether two things go together across her results.tallest and first to fall
- Choose the enquiry. Looking for what goes together in the results is pattern seeking. This is practice only.pattern seeking
- Write the answer. pattern seeking (practice only)
Check. The question is about what goes together. ✓
Method. Decide whether the question can be tested with evidence.
- Read the question. It asks which colour is best, which is a personal choice.best colour
- Decide. A personal choice cannot be tested, so the answer is no.opinion, not a test
- Write the answer. No. Accept any reason that says the question is an opinion, not a question we can test.
Check. Two people can give different answers. ✓
Method. A comparative test compares two or more things, and we can measure the result.
- Choose what to compare. We compare wet paper with dry paper.wet and dry paper
- Add a measure. We can time the snail on each paper.time each snail
- Write the answer. Accept any question that compares wet and dry paper and can be tested, such as “Do snails move faster on wet paper or dry paper?”
Check. A timer can measure how fast the snail moves. ✓
Setting up a fair test
A fair test is a test in which only one thing changes. We change the one thing we want to test. We measure what happens, and we keep everything else the same.
A comparative test compares the results for different things, such as three kinds of towel. If only the towel changes, the test is also a fair test.
A fair test helps us trust the answer. If we changed two things, we could not tell which one made the difference.
Key ideas
- In a fair test, only one thing changes.
- Measure the result of the change in the same way each time.
- Keep the other things the same: the size, the amount, the place and the way the test is done.
- If two things change, we cannot tell which one made the difference.
Method. Find the things that are different between the two tests.
- Read the material. The sponge and the cloth are different materials.material changes
- Read the size. The sponge is big and the cloth is small, so the size also changes.size changes too
- Write the answer. no
Check. Two things changed: the material and the size. ✓
Watch out. Use the same size of sponge and cloth, so that only the material changes.
Method. Find the thing that stays the same, then the thing that changes.
- Read the drop height. The drop height is 50 cm for every ball, so it stays the same.drop: 50 cm every time
- Find the thing that changes. The ball is different each time, so the ball changes.ball changes
- Write the answer. the ball
Check. The drop height stays at 50 cm. ✓
Method. Find the thing we change, and the things we keep the same.
- Read A. The kind of towel is the thing we change, so it does not stay the same.A: changes
- Read B and C. The amount of water and the pouring height are kept the same.B and C: same
- Write the answer. B and C
Check. Only the towel changes. ✓
Watch out
Watch out: a pupil who uses a bigger towel as well as a different kind of towel has changed two things. Check every thing before you start.
Try it at home or school (with a grown-up). Use three paper towels or kitchen cloths of the same size. Put a tray under each one. Pour the same amount of water (for example, 100 ml from a measuring jug) onto each one, from the same height. Compare how much water drips into the tray.
Exam tip
Grown-up tip. Ask your child: “What are we changing? What are we keeping the same?” Let them point to each thing as they name it.
Exercise 1B Fair tests and comparative tests
Method. Look for the thing that is different in each test.
- Read what we compare. We are comparing three towels.compare towels
- Find the thing that is different. Each test uses a different kind of towel.kind of towel
- Write the answer. the kind of paper towel
Check. The towel is the one thing that changes. ✓
Method. Think about the result we want to know.
- Think about the result. We want to know how much water did not soak into the towel.water in the tray
- Name the measurement. We measure the water that drips into the tray, in ml.ml in the tray
- Write the answer. the ml of water in the tray
Check. We measure the result, not the thing we change. ✓
Method. Check whether the amount of water stays the same.
- Read the amounts. One towel has 100 ml and the other has 50 ml.100 ml and 50 ml
- Decide. The amount of water changed, so the test is not fair.amount changed
- Write the answer. no
Check. The same amount of water must go on each towel. ✓
Method. Find the thing that we change.
- Find the thing we change. We change the kind of towel.kind of towel: changes
- Find the thing we keep the same. The size of the squares stays the same.size: same
- Write the answer. the size of the squares
Check. Only the kind of towel changes. ✓
Method. Think about what could change the bounce height besides the ball.
- Think about the test. The ball changes, so the other things must stay the same.ball changes
- Name one thing to keep. The drop height is one thing that must stay the same.drop height: same
- Write the answer. Accept any one of: the drop height, the table or the way the ball is dropped.
Check. Keep the same drop height, so that only the ball changes. ✓
Method. A comparative test compares results for different things.
- Read A. It compares two cups and what they hold.compares cups
- Read B. It asks for a personal view, so it is not a comparison.opinion
- Write the answer. A
Check. Two cups are compared with the same water. ✓
Method. Count how many things change.
- Count the changes. Three things change: the colour, the size and the weight.3 changes
- Decide. In a fair test only one thing changes.not fair
- Write the answer. no
Check. Change one thing only, and the test would be fair. ✓
Method. Think about the rule for a fair test.
- Think about the rule. Only one thing changes in a fair test.one thing
- Read the number. So the number of things that change is one.one
- Write the answer. 1
Check. One changed thing keeps the test fair. ✓
Method. Think about the rest of the test.
- Think about the rest. All the other things are kept the same.the same
- Check the rule. This is what makes the test fair.kept the same
- Write the answer. stay the same
Check. Keeping everything else the same makes the test fair. ✓
| Test | Towel | Water poured (ml) | Size of square (cm) |
|---|---|---|---|
| 1 | Cloth | 100 | 10 by 10 |
| 2 | Sponge | 100 | 10 by 10 |
| 3 | Cloth | 150 | 10 by 10 |
Method. Find the two tests where only one thing changes.
- Compare Test 1 and Test 2. The water (100 ml) and the size (10 by 10) are the same. Only the towel changes.only the towel
- Check Test 3. Test 3 has more water than Test 1, so two things change if we compare them with Test 1.water changes
- Write the answer. Tests 1 and 2
Check. Only the towel changes between Test 1 and Test 2. ✓
Method. Choose one thing to change, and keep the rest the same.
- Choose the thing to change. We want to compare balls, so the ball changes.the ball
- Keep the rest the same. The drop height and the table stay the same.drop height and table: same
- Write the answer. Accept any answer that names the ball as the thing that changes, such as “the ball”, because the drop height and the table stay the same.
Check. Only the ball changes in this plan. ✓
Method. Work out how much each towel soaked up. The biggest amount soaked up is the best towel.
- Work out the ml soaked up by each towel. Take the ml that dripped into the tray away from the 100 ml poured.A: 100 − 30 = 70; B: 100 − 12 = 88; C: 100 − 45 = 55
- Find the biggest amount. 88 ml is more than 70 ml and 55 ml.biggest: 88 ml
- Write the answer. Towel B
Check. Towel B soaked up 88 ml, the most of the three. ✓
Watch out. The number in the tray is not the amount soaked up. Take it away from 100 ml first.
Method. Count the things that changed, whatever their size.
- Count the changes. Two things changed: the towel and the pouring height.two changes
- Decide. When two things change we cannot tell which one made the difference, however small the changes are.not fair
- Write the answer. No. Accept any reason that says two things changed, so we cannot tell which one made the difference.
Check. Change only one thing for a fair test. ✓
Careful observations and accurate measurements
An observation is something we notice with our senses or with a tool. A careful observation looks closely, uses the same method each time, and records exactly what we see.
A measurement is a number with a unit, such as 7 cm, 60 ml or 18 °C. We use standard units: centimetres (cm), millilitres (ml), grams (g), kilograms (kg), seconds, minutes and degrees Celsius (°C).
To measure accurately:
- start a ruler at 0;
- read the scale at eye level, straight across from the mark;
- read to the nearest mark and write the unit;
- repeat the measurement to check it.
A thermometer measures temperature. The liquid inside rises when it gets warmer. A measuring cylinder measures the volume of a liquid in millilitres (ml). A data logger is a small electronic device that records readings, such as temperature, at set times.
Practice only: observing over time means looking at the same thing again and again and writing down what changes. It is practice for careful observation, and it is not a separate statement.
Key ideas
- Use standard units, and write the unit with every measurement.
- Start a ruler at 0 and read it at eye level.
- A thermometer measures temperature in degrees Celsius (°C).
- A data logger records readings at set times, without a person.
Method. Read the scale, then find the mark that the red liquid reaches.
- Find the scale. The numbers go up in steps of 5, with a small mark for each degree.0, 5, 10, 15, 20, 25, 30
- Find the level of the red liquid. The liquid stops above the 15 mark, at the third small mark.above 15
- Count the marks above 15. Three small marks above 15 make 18.15 + 3 = 18
- Write the answer. 18 °C
Check. The thermometer reads 18 degrees, the same as the data logger at 11 am. ✓
Watch out. Read the number on the scale, then add the small marks. Do not guess.
Method. Start at 0, then read the other end of the stick.
- Find the 0 mark. Measuring starts at 0, so the stick begins at 0.starts at 0
- Read the other end. The end of the stick is at the 7 cm mark.ends at 7
- Write the length with the unit. A length is written in centimetres, cm.7 cm
- Write the answer. 7 cm
Check. Count along the ruler from 0 to 7, one centimetre at a time. ✓
Watch out. If you do not start at 0, the answer will be wrong.
Method. Find the scale, then read the level of the water.
- Find the scale. The numbers go up in steps of 20 ml, with a mark every 10 ml.0, 20, 40, 60, 80, 100
- Find the water level. The blue line is at the mark for 60 ml.blue line at 60
- Write the answer with the unit. The volume of a liquid is measured in ml.60 ml
- Write the answer. 60 ml
Check. The blue line sits level with the 60 mark. ✓
Watch out. Read the scale at eye level. Looking from above or below can give a wrong number.
Watch out
Watch out: a measurement with no unit does not say what was measured. “7” could mean 7 cm, 7 ml or 7 °C.
Try it at home or school (with a grown-up). Pour 100 ml of water into a jar, using a measuring jug. Put a strip of tape on the jar to mark the water level. Look at the jar at the same time each day for a few days, and write down the level. (This is practice only: observing over time.)
Exam tip
Grown-up tip. Ask: “What is the unit? Where does the scale start? Can you read it again, at eye level?”
Exercise 1C Careful observations and accurate measurements
Method. Find the 5 mark, then count the small marks above it.
- Find the 5 mark. The number 5 is labelled on the scale.5
- Count the small marks above 5. The liquid stops two small marks above 5.5 + 2 = 7
- Write the answer. 7 °C
Check. Two marks above 5 is 7 degrees. ✓
Method. Start at 0 and read the end of the stick.
- Find the 0 mark. The stick starts at 0.starts at 0
- Read the end. The stick ends at the 9 cm mark.ends at 9 cm
- Write the answer. 9 cm
Check. Count from 0 to 9 along the ruler. ✓
Method. Read the level of the water on the scale.
- Find the scale. The numbers go up in steps of 20 ml.0, 20, 40
- Read the water level. The blue line is at the 40 mark.blue line at 40
- Write the answer. 40 ml
Check. The level is at 40 ml. ✓
Method. Think about what mass is, and which unit measures it.
- Think about mass. Mass is how heavy something is. A pencil case is light.light: grams
- Check the other unit. Kilometres measure distance, not mass.km: distance
- Write the answer. g
Check. Grams are used for small masses. ✓
Method. Think about the tool for temperature.
- Think about the job. We want to know how hot or cold something is.temperature
- Name the tool. A thermometer measures temperature in degrees Celsius.thermometer
- Write the answer. thermometer
Check. A ruler measures length, not temperature. ✓
Method. Compare the two lengths using the same unit.
- Change the units. 1 cm = 10 mm, so 6 cm = 60 mm.6 × 10 = 60
- Compare. The two lengths are equal.60 mm = 60 mm
- Write the answer. the same length
Check. 6 cm is the same as 60 mm. ✓
Method. Change both masses to the same unit.
- Change the units. 1 kg = 1000 g.1000 g
- Compare. 1000 g is more than 900 g.1000 > 900
- Write the answer. 1 kg
Check. 1 kg is heavier than 900 g. ✓
Method. Think about where your eyes should be.
- Think about the reading. The level of the water is seen most clearly straight across.straight across
- Choose the answer. Reading at eye level helps to avoid a wrong reading.eye level
- Write the answer. eye level
Check. Look straight across at the water level. ✓
Method. A standard unit is a unit that everyone agrees on, such as cm.
- Read A. Spoons are not a standard unit.A: spoons
- Read B. Centimetres are a standard unit.B: cm
- Write the answer. B
Check. Centimetres are a unit that everyone agrees on. ✓
Method. Think about what a data logger does.
- Think about the job. A data logger records readings at set times, by itself.by itself
- Decide. So nobody has to write each reading down as it happens.no person needed
- Write the answer. no
Check. The data logger records 17 °C at 10 am on its own. ✓
Method. Think about what we want to see over time.
- Think about the change. We want to see how the level changes from day to day.change each day
- Choose the record. A table with a reading for each day shows the change. One reading does not.table
- Write the answer. a table with a level for each day
Check. Each day gives a new reading to compare. ✓
Method. Think about how each measurement was made.
- Look at Aisha. She read the ruler at a slant, which can give a wrong number.slant
- Look at Ben. He read from 0 at eye level, but the two answers still differ, so both should check again.differ
- Write the answer. Accept any answer that says both should measure again, reading from 0 at eye level, because a slanted reading can give a wrong number.
Check. Repeat the measurement to check the answer. ✓
Method. A careful observation says what we see and how we know.
- Choose what to observe. We observe the leaf.leaf
- Add a tool or unit. A unit or a tool shows how the observation was made.cm or ruler
- Write the answer. Accept any careful observation that uses a tool or a unit, such as “The leaf is 6 cm long, measured with a ruler.”
Check. A tool or a unit makes the observation careful and checkable. ✓
Recording, classifying and presenting data
When we record results, we write them down straight away, in a table, with units. When we classify, we put things into groups using a rule.
A key is a set of yes or no questions. You answer each question in order, and each answer leads you to a group. A key helps other people sort things in the same way.
We can present data in different ways:
- a table, with a row for each thing and a column for each measurement;
- a bar chart, where the height of each bar shows the number;
- a labelled diagram, with a label for each part and a short title;
- a drawing that shows what we saw.
| Object | Material |
|---|---|
| wooden ruler | wood |
| metal paper clip | metal |
| plastic cup | plastic |
| wooden spoon | wood |
| cardboard box | cardboard |
Key ideas
- A table records each thing and its result, with a unit.
- A key uses yes or no questions, in order, to sort things into groups.
- A bar chart needs a title, labels and a scale.
- A labelled diagram names each part, so that a reader can understand it.
Method. Start at the top of the key and follow the answers.
- Start at the top. The first question is: is it made of wood?Is it made of wood?
- Answer the question for the spoon. A wooden spoon is made of wood, so the answer is yes.wood: yes
- Follow the yes arrow. A yes takes us to the wood group, so we stop there.wood group
- Write the answer. wood
Check. The wooden spoon is in the wood group. ✓
Watch out. Start at the top every time, and answer the first question for each object.
Method. Find the bar for Towel B, then read the top of the bar on the scale.
- Find the bar for Towel B. It is the middle bar.Towel B
- Read the top of the bar. The bar reaches the 88 mark on the scale, in ml.88 ml
- Write the answer. 88 ml
Check. Towel B soaked up 88 ml, the most of the three. ✓
Watch out. Read the value on the bar, and write the unit ml.
Method. Find the label on the dashed line, then check the ruler.
- Find the label. The label on the dashed line says drop 50 cm.drop 50 cm
- Check the ruler. The dashed line lines up with the 50 mark on the ruler.50 on the ruler
- Write the answer. 50 cm
Check. The label and the ruler both show 50 cm. ✓
Watch out
Watch out: a bar chart without a title or units cannot be read properly. Always write what the numbers mean.
Try it at home or school (with a grown-up). Find five things from around your home that are made of different materials, such as wood, metal, plastic, paper or cloth. Make a yes or no key to sort them into groups. Ask someone else to sort the things using your key.
Exam tip
Grown-up tip. Ask your child to read each question of the key aloud, in order. If a thing does not fit, ask them to change the key, not the answer.
Exercise 1D Recording, classifying and presenting data
Method. Follow the key for the plastic cup.
- Question 1. Is it made of wood? A plastic cup is not made of wood, so the answer is no.no
- Question 2. Is it made of metal? A plastic cup is not made of metal, so the answer is no.no
- Find the group. Both answers are no, so the cup goes in the other group.other
- Write the answer. other
Check. The plastic cup is not wood and not metal. ✓
| Object | Material |
|---|---|
| wooden ruler | wood |
| metal paper clip | metal |
| plastic cup | plastic |
| wooden spoon | wood |
| cardboard box | cardboard |
Method. Use the key. Count the objects that end up in the wood group.
- Follow the key for each object. Ask the yes or no questions in order.wooden ruler, wooden spoon
- Count the objects in the group. There are 2 objects that end in the wood group.1 + 1 = 2
- Write the answer. 2
Check. Count the names in the list again: 2. ✓
Watch out. Check every object against the first question, not only the first one you see.
Method. Use the key. Count the objects that end up in the metal group.
- Follow the key for each object. Ask the yes or no questions in order.metal paper clip
- Count the objects in the group. There is 1 object that end in the metal group.1 = 1
- Write the answer. 1
Check. Count the names in the list again: 1. ✓
Watch out. Check every object against the first question, not only the first one you see.
Method. Use the key. Count the objects that end up in the other group.
- Follow the key for each object. Ask the yes or no questions in order.plastic cup, cardboard box
- Count the objects in the group. There are 2 objects that end in the other group.1 + 1 = 2
- Write the answer. 2
Check. Count the names in the list again: 2. ✓
Watch out. Check every object against the first question, not only the first one you see.
Method. Count the groups of five first. Then count the marks left over.
- Count the full groups. One full group has five marks.1 group = 5 marks
- Count the marks left over. Three single marks are left over.3 marks
- Add them together. Five and three make eight.5 + 3 = 8
- Write the answer. 8
Check. Count all the marks one at a time, and you get 8. ✓
| Group | Number of objects |
|---|---|
| wood | 2 |
| metal | ? |
| other | 2 |
Method. Use the total of five objects to find the missing number.
- Find the total. There are five objects in all.total = 5
- Add the known groups. The wood group and the other group make 4 objects.2 + 2 = 4
- Find the missing number. The total is 5, so the metal group has 5 minus 4 objects.5 − 4 = 1
- Write the answer. 1
Check. The metal group has 1 object: 2 + 1 + 2 = 5. ✓
Method. Read the label on the ruler, then look at its marks.
- Read the label. The label on the ruler says ruler, cm.ruler, cm
- Look at the marks. The marks go up from the table, in centimetres, from 0 to 60.marks: 0 to 60 cm
- Write the answer. height in cm
Check. The ruler measures how high the ball is above the table. ✓
Method. Think about which way makes the numbers easy to compare.
- Think about a list with no units. A list with no units does not say what the numbers mean.no units
- Choose the best way. A bar chart shows the three values side by side, with a scale.bar chart
- Write the answer. a bar chart
Check. A bar chart lets us compare the three towels at a glance. ✓
Method. Find the bar for Towel C, then read its top.
- Find the bar for Towel C. It is the last bar.Towel C
- Read the top of the bar. The bar reaches 55 on the scale, in ml.55 ml
- Write the answer. 55 ml
Check. Towel C soaked up 55 ml. ✓
Method. Follow the key for the paper clip.
- Question 1. Is it made of wood? A metal paper clip is not wood, so the answer is no.no
- Question 2. Is it made of metal? Yes, a paper clip is made of metal.yes
- Find the group. The yes arrow leads to the metal group.metal
- Write the answer. metal
Check. Follow the arrows, and check the group name. ✓
Method. The question must split the cardboard box away from the other objects.
- Look at the cardboard box. The cardboard box is the only object made of cardboard.cardboard
- Write the question. A question about cardboard puts the box alone in its group.is it cardboard?
- Write the answer. Accept any yes or no question that separates the cardboard box from the other objects, such as “Is it made of cardboard?”
Check. Only the cardboard box answers yes. ✓
Reporting findings and drawing conclusions
A report tells other people what you did and what you found. It can be spoken or written, and it can include a display of your results. Use the same order each time:
A conclusion is a short sentence that says what the results show. It must match the results, not what you wish had happened.
A prediction is a sensible guess about a new value, based on a pattern in your results. We check it by testing. For example, if each book in a stack is 3 cm thick, we can predict the height of 5 books: 5 × 3 cm = 15 cm.
To suggest an improvement, think about what made the test less fair or less accurate, and how to fix it. To raise a further question, ask a new question that the test makes you wonder about.
Key ideas
- A report says what we did, what we found, what it means and what we will test next.
- A conclusion must match the results.
- A prediction is a guess based on a pattern, and we test it to check it.
- Suggest improvements, and raise further questions.
Method. Find the biggest result, then say what it shows.
- Find the biggest amount. Towel B soaked up 88 ml, which is the most.88 ml is the biggest
- Write a sentence about the results. The conclusion says what the results show.Towel B soaked up the most water
- Write the answer. Towel B soaked up the most water.
Check. The conclusion matches the biggest result, 88 ml. ✓
Watch out. A conclusion is not what you hoped would happen. It is what the results show.
Method. Use the pattern in the test: each book adds the same height to the stack.
- Find the pattern in the results. Each book is the same thickness, so the stack grows by the same amount.1 book = 3 cm; 2 books = 6 cm; 3 books = 9 cm
- Predict the height for 5 books. Multiply the thickness of one book by 5.5 × 3 = 15
- Write the answer. 15 cm
Check. Add 3 cm for each book: 5 books is 15 cm. ✓
Watch out. A prediction is a sensible guess from the pattern. It is only checked when we measure it.
Method. Find the thing that changed, then choose a fix that keeps it the same.
- Find the thing that changed. The pouring speed changed, which is a second thing that changed.pouring speed
- Choose a fix. Pour at the same speed for every towel, so only the towel changes.same speed
- Write the answer. Pour at the same speed for every towel
Check. Only the towel now changes. ✓
Watch out
Watch out: a prediction is not proof. It is a guess that we must test. Always say that a prediction is a guess until it is tested.
Try it at home or school (with a grown-up). Stack identical books, or identical boxes, one on top of another. Measure the height of the stack with a ruler after one, two and three. Predict the height of four, then check it by measuring.
Exam tip
Grown-up tip. Ask your child to tell you the story of their test in three sentences: what we did, what we found, what it means.
Exercise 1E Reporting, conclusions and predictions
Method. A report sentence says what was done and what was found.
- Name the towel. The report is about Towel B.Towel B
- Add the result. The result is 88 ml soaked up.88 ml
- Write the answer. Accept any sentence that says Towel B soaked up 88 ml of water.
Check. Write the towel, the result and the unit in one sentence. ✓
Method. A conclusion says what the results show, not a personal choice.
- Read the first sentence. It says what the results show: 88 ml is the most.results
- Read the second sentence. It is a personal choice, so it is not a conclusion from the results.opinion
- Write the answer. Towel B soaked up the most water.
Check. Only the first sentence comes from the results. ✓
Method. Use the pattern in the test: each book adds the same height to the stack.
- Find the pattern in the results. Each book is the same thickness, so the stack grows by the same amount.1 book = 3 cm; 2 books = 6 cm; 3 books = 9 cm
- Predict the height for 6 books. Multiply the thickness of one book by 6.6 × 3 = 18
- Write the answer. 18 cm
Check. Add 3 cm for each book: 6 books is 18 cm. ✓
Watch out. A prediction is a sensible guess from the pattern. It is only checked when we measure it.
| Day | ml left in the jar |
|---|---|
| Day 1 | 80 |
| Day 2 | 72 |
| Day 3 | 64 |
Method. Find how much the water level falls each day, then continue the pattern for one more day.
- Find the fall from day 1 to day 2. Take the day 2 reading from the day 1 reading.80 − 72 = 8 ml
- Check the fall from day 2 to day 3. The fall is the same, so the pattern is steady.72 − 64 = 8 ml
- Continue the pattern to day 4. Take 8 ml away from the day 3 reading.64 − 8 = 56 ml
- Write the answer. 56 ml
Check. 56 + 8 = 64, the day 3 reading. ✓
Watch out. This is a prediction from three readings. It is not a fact until we measure day 4.
Method. Think about what could make the test unfair or inaccurate.
- Find a weak point. If the drop height changes, the test is not fair.drop height
- Suggest a fix. Drop each ball from the same height, and repeat each drop to check.same height, repeat
- Write the answer. Accept any improvement that makes the test fairer or more accurate, such as dropping each ball from the same height or repeating each drop.
Check. Repeating and keeping the height the same makes the test more reliable. ✓
Method. A further question is one that the test makes us wonder about.
- Read A. A thicker towel is a new thing to test, so this is a good further question.A: new test
- Read B. The colour of the tray does not link to what the test found.B: not linked
- Write the answer. A
Check. Question A can be tested with the same method. ✓
Method. Compare the results with the conclusion.
- Find the biggest result. Towel B soaked up 88 ml, which is the most.88 ml
- Check the conclusion. Towel A soaked up 70 ml, which is less than 88 ml.70 is not the most
- Write the answer. no
Check. The conclusion does not match the results. ✓
Method. Find the smallest result.
- Compare the results. The results are 70, 88 and 55 ml.70, 88, 55
- Find the smallest. The smallest number of ml soaked up is 55.55 is the smallest
- Write the answer. Towel C
Check. Towel C soaked up the least. ✓
Method. Read the result for that towel.
- Find the towel. Towel C is the towel from part (a).Towel C
- Read its result. Towel C soaked up 55 ml.55 ml
- Write the answer. 55 ml
Check. Towel C soaked up 55 ml. ✓
Method. Use the pattern in the test: each book adds the same height to the stack.
- Find the pattern in the results. Each book is the same thickness, so the stack grows by the same amount.1 book = 3 cm; 2 books = 6 cm; 3 books = 9 cm
- Predict the height for 8 books. Multiply the thickness of one book by 8.8 × 3 = 24
- Write the answer. 24 cm
Check. Add 3 cm for each book: 8 books is 24 cm. ✓
Watch out. A prediction is a sensible guess from the pattern. It is only checked when we measure it.
Method. Think about how much evidence one test gives.
- Look at the test. Three towels in one test give some evidence about those towels only.three towels
- Decide. To prove a claim for all towels we need more tests with many kinds of towel.more tests
- Write the answer. No. Accept any reason that says three towels in one test cannot prove this for all towels, and that more tests would be needed.
Check. One test gives evidence, not proof for everything. ✓
Method. Compare the two results and say what they show.
- Compare the results. The rubber ball bounced to 38 cm and the sponge ball to 9 cm.38 and 9
- Write the conclusion. The bigger bounce is the rubber ball.rubber ball higher
- Write the answer. Accept any conclusion that says the rubber ball bounced higher (38 cm) than the sponge ball (9 cm).
Check. 38 cm is more than 9 cm. ✓
Differences, similarities and evidence
To compare two things, look for differences (what is not the same) and similarities (what is the same). A change is something that becomes different over time, or after a test.
Evidence is information that helps us answer a question or support an idea. Measurements from our own test are evidence. So are facts from a reliable source, checked with a grown-up.
| Feature | Rubber ball | Sponge ball |
|---|---|---|
| Shape | round | round |
| Material | rubber | sponge |
| Bounce from 50 cm | 38 cm | 9 cm |
Evidence supports a finding when it points to the same answer. One test with one of each ball is some evidence, but it is not enough to be sure about all balls.
Practice only: pattern seeking means looking across your results for things that go together, such as taller stacks having more books. Secondary sources means finding facts in a book or a reliable website, checked with a grown-up. These are practice only, and they are not separate statements.
Key ideas
- A difference is something that is not the same.
- A similarity is something that is the same.
- Evidence is measured, or reliable, information that helps to answer a question.
- One test is not always enough to prove something for all cases.
Method. Decide which statement describes something that is not the same.
- Read A. Both balls are round, so this is a similarity.A: same
- Read B. The rubber ball bounced to 38 cm and the sponge ball to 9 cm, so the heights are different.B: different
- Write the answer. B
Check. The bounce heights are different. ✓
Method. Find a feature that is the same in both columns.
- Look at the shape. The table says round for both balls.round: rubber, round: sponge
- Find the same thing. The same word in both columns is a similarity.round = round
- Write the answer. both are round
Check. The shape is the same for both balls. ✓
Method. Read the evidence, and check whether it supports the idea.
- Read the evidence. The rubber ball bounced to 38 cm.38 cm
- Compare it with the other ball. The sponge ball bounced to only 9 cm, so the rubber ball bounced higher in this test.38 is more than 9
- Write the answer. yes
Check. The measurements point to the same answer. ✓
Watch out
Watch out: “I think” is not evidence. A measurement is evidence, because someone else can measure it again and check it.
Try it at home or school (with a grown-up). Drop two different balls from the same height, with a grown-up. Measure how high each one bounces, using a ruler. Write one difference and one similarity from your results. Then decide whether one test is enough to say what happens for all balls.
Exam tip
Grown-up tip. Ask: “Is that a measurement or a guess? How could someone else check it?”
Exercise 1F Differences, similarities and evidence
Method. A difference is a feature that is not the same in both columns.
- Look at the material. Rubber and sponge are different materials.rubber and sponge
- Look at the bounce height. The bounce heights are 38 cm and 9 cm.38 and 9
- Write the answer. Accept any difference in the table, such as the material or the bounce height.
Check. The two balls differ in material and in bounce height. ✓
Method. Compare the two bounce heights.
- Read the heights. Rubber ball 38 cm, sponge ball 9 cm.38 and 9
- Find the lower one. 9 cm is less than 38 cm.sponge ball
- Write the answer. sponge ball
Check. 9 cm is the smaller bounce. ✓
Method. Find the two bounce heights, then take the smaller one away from the bigger one.
- Read the rubber ball bounce. It bounced to this height.rubber ball: 38 cm
- Read the sponge ball bounce. It bounced to this height.sponge ball: 9 cm
- Take the smaller height away from the bigger one. The difference is how much higher.38 − 9 = 29
- Write the answer. 29 cm
Check. 9 + 29 = 38, so the sums match. ✓
Watch out. Subtract the smaller number from the bigger number.
Method. Evidence is a measurement or reliable information, not a personal view.
- Read A. This is a personal view, so it is not evidence.opinion
- Read B. This is a measurement, so it is evidence.measurement
- Write the answer. B
Check. A measurement can be checked by someone else. ✓
Method. Look for a number with a unit.
- Look for a number. The sentence gives 38 cm.38 cm
- Decide. A number with a unit is a measurement.measurement
- Write the answer. measurement
Check. The number and unit come from a measurement. ✓
Method. Look across the three results for a pattern.
- Read the heights. The heights are 3 cm, 6 cm and 9 cm.3, 6, 9
- Compare them. Each extra book makes the stack taller, so the height goes up.goes up
- Write the answer. yes
Check. The heights get bigger each time. ✓
Method. A reliable source is one that is checked, not a guess.
- Read A. A checked book or website gives facts that someone recorded.A: checked
- Read B. A guess is not a reliable source.B: a guess
- Write the answer. A
Check. A reliable source gives checked facts. ✓
Method. Compare the two bounce heights.
- Read the heights. Rubber ball 38 cm, sponge ball 9 cm.38 and 9
- Find the higher one. 38 cm is more than 9 cm.rubber ball
- Write the answer. rubber ball
Check. The rubber ball bounced higher. ✓
Method. Think about what is being measured.
- Think about the measure. A bounce height is a length.length
- Choose the unit. Lengths are measured in centimetres, cm.cm
- Write the answer. cm
Check. Millilitres measure volume, not height. ✓
Method. Think about how much evidence one test gives.
- Count the balls tested. Only one rubber ball and one sponge ball were tested.one of each
- Decide. One test with one ball of each kind is not enough to prove what happens for all balls.not enough
- Write the answer. no
Check. More tests would be needed to be sure. ✓
Method. Take the smaller amount away from the bigger amount.
- Read the two amounts. Towel A soaked up 70 ml. Towel C soaked up 55 ml.70 and 55
- Take the smaller away from the bigger. The difference is how many ml more.70 − 55 = 15
- Write the answer. 15 ml
Check. 55 + 15 = 70, so the answer is right. ✓
Method. Think about how many balls were tested.
- Think about the test. We tested one rubber ball and one sponge ball.one of each
- Decide. The word always needs evidence from many balls, so more tests would be needed.more tests
- Write the answer. Accept any answer that says one test with one ball of each kind is not enough evidence to say always, and more tests would be needed.
Check. Evidence from a few balls cannot prove a rule for all balls. ✓
Method. A pattern question asks what goes together in the results.
- Choose a pattern. Taller stacks may go with more books.taller and more
- Say what kind of question it is. Looking for patterns is practice only in this chapter.practice only
- Write the answer. Accept any pattern question about our results, such as “Do taller stacks have more books?”, and the words practice only.
Check. A question that looks across results is pattern seeking. ✓
Chapter summary
| Skill | Method |
|---|---|
| Ask relevant questions | A relevant question is about what we study and can be answered with evidence. Know the type of enquiry to use. |
| Fair test | Change one thing, measure the result and keep everything else the same. |
| Measure carefully | Use standard units, start a ruler at 0, read at eye level, and use a thermometer, a measuring cylinder or a data logger. |
| Record and classify | Record results at once, with units. Sort things with a key of yes or no questions. |
| Present data | Use a table, a bar chart, a labelled diagram or a drawing. Give it a title and labels. |
| Report and conclude | Say what you did and found. Write a conclusion that matches the results. Predict from a pattern, then test. |
| Compare and use evidence | Find differences and similarities. Use evidence from tests to answer a question or support a finding. |
Can you…?
- I can ask a question that I can test, and say which type of enquiry would answer it
- I can set up a fair test in which only one thing changes
- I can measure with standard units, and read a scale at eye level
- I can use a thermometer, a measuring cylinder and a data logger
- I can record, classify and present data in a table, a key, a bar chart or a labelled diagram
- I can write a report, a conclusion and a prediction that match my results
- I can suggest an improvement and raise a further question
- I can compare differences and similarities, and use evidence to support an idea
Key terms
- relevant question
- a question about the thing we are studying that we can answer with evidence
- enquiry
- a way of finding out, such as a test, an observation or a search in a reliable source
- fair test
- a test in which only one thing changes and everything else is kept the same
- comparative test
- a test that compares the results for different things
- observation
- something we notice with our senses or with a tool
- measurement
- a number with a unit, such as 7 cm or 60 ml
- thermometer
- a tool that measures temperature in degrees Celsius
- data logger
- a small electronic device that records readings at set times
- key
- a set of yes or no questions used to sort things into groups
- conclusion
- a short sentence that says what the results show
- prediction
- a sensible guess about a new value, based on a pattern, which we then test
- evidence
- information from measurements or reliable sources that helps answer a question
- practice only
- an enquiry skill used as practice in this chapter, which is not a separate statement
Exercise 1Z Check-up
Method. A relevant question can be answered with evidence.
- Read A. This is a personal view, so it is not a science question.A: opinion
- Read B. We can measure how much water soaks in.B: measure
- Write the answer. B
Check. Measuring the water gives the answer. ✓
Method. Think about what must be kept the same in a fair test.
- Think about the test. Only the towel changes in a fair test.towel changes
- Name the thing kept the same. The same amount of water is poured on each towel.the amount of water
- Write the answer. the amount of water
Check. The amount of water is kept the same. ✓
Method. Find the 10 mark, then count the small marks above it.
- Find the 10 mark. The number 10 is labelled on the scale.10
- Count the small marks above 10. The liquid stops four small marks above 10.10 + 4 = 14
- Write the answer. 14 °C
Check. Four marks above 10 is 14 degrees. ✓
Method. Follow the key for the wooden ruler.
- Question 1. Is it made of wood? A wooden ruler is made of wood, so the answer is yes.yes
- Find the group. The yes arrow leads to the wood group.wood
- Write the answer. wood
Check. The wooden ruler is in the wood group. ✓
Method. Find the bar for Towel A, then read its top.
- Find the bar for Towel A. It is the first bar.Towel A
- Read the top of the bar. The bar reaches 70 on the scale, in ml.70 ml
- Write the answer. 70 ml
Check. Towel A soaked up 70 ml. ✓
Method. Take the smaller amount away from the bigger amount.
- Read the two amounts. Towel B soaked up 88 ml. Towel C soaked up 55 ml.88 and 55
- Take the smaller away from the bigger. The difference is how many ml more.88 − 55 = 33
- Write the answer. 33 ml
Check. 55 + 33 = 88, so the answer is right. ✓
Method. Use the pattern in the test: each book adds the same height to the stack.
- Find the pattern in the results. Each book is the same thickness, so the stack grows by the same amount.1 book = 3 cm; 2 books = 6 cm; 3 books = 9 cm
- Predict the height for 5 books. Multiply the thickness of one book by 5.5 × 3 = 15
- Write the answer. 15 cm
Check. Add 3 cm for each book: 5 books is 15 cm. ✓
Watch out. A prediction is a sensible guess from the pattern. It is only checked when we measure it.
Method. A conclusion says what the results show.
- Compare the results. Towel B soaked up 88 ml and Towel C soaked up 55 ml.88 and 55
- Write the conclusion. The bigger amount soaked up is Towel B.Towel B more
- Write the answer. Accept any conclusion that says Towel B soaked up more water than Towel C.
Check. The conclusion matches the results. ✓
Method. Compare the two bounce heights.
- Read the heights. Rubber ball 38 cm, sponge ball 9 cm.38 and 9
- Find the higher one. 38 cm is more than 9 cm.rubber ball
- Write the answer. rubber ball
Check. 38 is more than 9. ✓
Method. Look at the picture and think about its job.
- Look at the device. The picture shows a box with a screen and a reading on it.box with a screen
- Name the tool. A data logger records readings at set times, by itself.data logger
- Write the answer. data logger
Check. The data logger records readings without a person. ✓
Total 16 marks. Allow about 16 minutes.
Exercise 1X Practice test questions
Method. Look for the one thing that is different in each test.
- Read the test. Each test uses a different kind of paper towel.kind of towel
- Name the thing that changes. Only this thing changes in a fair test.the kind of paper towel
- Write the answer. the kind of paper towel
Check. Everything else is kept the same. ✓
Method. Think about which tool measures volume of a liquid.
- Read A. A ruler measures length, not volume.A: length
- Read B. A measuring cylinder measures volume in ml.B: ml
- Write the answer. B
Check. A measuring cylinder reads ml directly. ✓
| Test | Ball | Drop height | Bounce height |
|---|---|---|---|
| 1 | rubber ball | 50 cm | 38 cm |
| 2 | sponge ball | 50 cm | 9 cm |
Method. Find the two tests where only one thing changes.
- Compare the drop heights. Both tests use a drop height of 50 cm.50 cm and 50 cm
- Compare the balls. Only the ball is different, so only one thing changes.only the ball
- Write the answer. Tests 1 and 2, because only the ball changes
Check. The drop height stays the same in both tests. ✓
Method. Find the 20 mark, then count the small marks above it.
- Find the 20 mark. The number 20 is labelled on the scale.20
- Count the small marks above 20. The liquid stops two small marks above 20.20 + 2 = 22
- Write the answer. 22 °C
Check. Two marks above 20 is 22 degrees. ✓
Method. Read the two bars, then take the smaller number away from the bigger one.
- Read the wood bar. The wood group has 2 objects.wood: 2
- Read the metal bar. The metal group has 1 object.metal: 1
- Take the smaller away from the bigger. The difference is how many more.2 − 1 = 1
- Write the answer. 1
Check. 1 + 1 = 2, the wood group size. ✓
Method. Find the height of one box, then multiply by 5.
- Find one box. Three boxes make 36 cm, so one box is 36 divided by 3.36 ÷ 3 = 12 cm
- Predict for 5 boxes. Five boxes, each 12 cm, make 60 cm.5 × 12 = 60
- Write the answer. 60 cm
Check. Three boxes at 12 cm each make 36 cm. ✓
Method. Think about the job of a data logger.
- Think about the job. A data logger records readings at set times by itself.by itself
- Give the reason. Nobody has to write each reading down, so fewer readings are missed.no writing needed
- Write the answer. Accept any reason that says it records readings automatically, at set times, without a person writing each reading down.
Check. Automatic recording saves time and reduces mistakes. ✓
Method. Think about the rules for accurate measuring.
- Think about the start. Measuring starts at the 0 mark.start at 0
- Think about the reading. The scale is read straight across, at eye level.eye level
- Write the answer. Accept any answer that says the stick started at 0 and the scale was read at eye level.
Check. Both rules make the measurement accurate. ✓
Method. Check each statement against the results.
- Read A. Towel C soaked up 55 ml, which is the least, so statement A is not supported.55 is the least
- Read B. Towel B soaked up 88 ml, which is the most, so statement B is supported.88 is the most
- Write the answer. B
Check. The results support only statement B. ✓
Method. Use the three parts of a fair test: change, measure and keep the same.
- Change. We change the sponge: we use a different sponge each time.the sponge
- Measure. We measure the ml of water in the tray, or the ml soaked up.ml in the tray
- Keep the same. We keep the same amount of water and the same pouring height.same water and height
- Write the answer. Accept any plan that changes the sponge, measures the ml of water in a tray or the ml soaked up, and keeps one thing the same, such as the amount of water.
Check. Change one thing, measure the result and keep everything else the same. ✓