Free textbooks › Year 7 Science textbook
KS3 Science · Year 7Chapter 1 · Working scientifically (KS3)
Year 7 · Chapter 1

Working scientifically (KS3)

By the end of this chapter you will be able to

  • Name the independent, dependent and control variables in a fair test
  • Plan a fair test and a risk assessment for a practical
  • Find a mean from repeat readings and spot an anomaly
  • Work out a range as a simple measure of uncertainty
  • Choose and draw a suitable table or graph, with labels and units
  • Write a conclusion that matches the data, and evaluate a method

You should already know

  • Fair tests and tables from primary school science
  • Reading scales and measuring with rulers and timers

Where this leads

  • Cells and microscopes, which uses magnification and measurement (Chapter 2)
  • Every later chapter uses these skills in its practical sections

National Curriculum for England, Key Stage 3 science, Year 7. Content: WS1 ask questions, plan enquiries and fair tests, and identify and control variables, WS2 assess risk and use apparatus and materials safely, WS3 take measurements with accuracy and precision, and repeat readings where needed, WS4 record and present data in tables, bar charts, line graphs and scatter graphs, WS5 evaluate methods, evidence and conclusions, including anomalies and uncertainty, WS6 use scientific models and evidence to support or refute ideas.

Exercise P  Do you remember?

1
FWhat is a test called in which only one thing is changed and everything else is kept the same? Write the two words.
2
FHow many centimetres are in 1 metre? Write the number.
3
FWhat is the mean of 4, 6 and 8? Write the number.
4
FWhat do we call the variable that we change on purpose in an experiment? Write the two words.
5
FWhich tool measures time more precisely: a clock that shows minutes, or a stopwatch that shows hundredths of a second? Write the word: clock or stopwatch.
1.1

Asking questions and variables

Year 7
WS1: ask questions and make predictions that can be tested; identify variables in an enquiry
Video lesson: Asking questions and variablesComing soon
Story. Ruby wants to know whether a toy car travels further when it starts from a higher ramp. She writes her question, then predicts what she thinks will happen. Her teacher says, “A good question names what you will change and what you will measure.”

Good scientific questions can be tested by collecting data. A prediction is what you expect to happen, and it should give a reason. A hypothesis is a testable statement that links two variables.

In an enquiry there are three kinds of variable:

30 cmramp height (cm)
The ramp test: the height of the ramp is changed, and the distance travelled is measured.

Key ideas

  • A testable question names an independent variable and a dependent variable.
  • A prediction states what you expect and gives a reason.
  • Control variables are kept the same so the test is fair.
  • Only one independent variable should change in a fair test.
Worked example 1.1.1
In Ruby's ramp test, which variable is changed on purpose? Write the words.

Method. Find the variable we deliberately change.

  1. Read the question. Ruby changes how high the ramp is, on purpose.
    height of the ramp
  2. Name the variable. The changed variable is the independent variable.
    independent variable
  3. Write the answer.
    the height of the ramp

Check. The distance is the variable that is measured. ✓

Worked example 1.1.2
In the same test, which variable is measured? Write the words.

Method. Find the variable we record.

  1. Read the question. Ruby records how far the car travels on the floor.
    distance travelled
  2. Name the variable. This is the dependent variable, because it depends on the height.
    dependent variable
  3. Write the answer.
    the distance travelled

Check. Changing the height changes the distance. ✓

Worked example 1.1.3
Give one control variable for this test. Write one thing that stays the same.

Method. Think about what else could affect the distance.

  1. List the factors. The car, the floor and the starting point could all affect the distance.
    car, floor, starting point
  2. Choose one. We keep the same car each time.
    the same car
  3. Write the answer.
    the same car

Check. Other control variables include the floor and the starting point. ✓

Watch out

Watch out: a control variable is kept the same. Do not write the thing that is changed, and do not write the thing that is measured.

Exam tip

Exam tip. When asked for a variable, name it clearly, for example “the height of the ramp”, not just “height”.

Try it (with your teacher, or a grown-up at home). Ask a question that you can test with a ruler and a toy car on a book, such as “Does a steeper slope make the car go further?” Write the independent variable, the dependent variable and two control variables before you start.

Exercise 1A  Asking questions and variables

1
FIn the ramp test, which variable is changed on purpose? Write the words.
2
FIn the ramp test, which variable is measured? Write the words.
3
FGive one control variable for the ramp test. Write one thing that stays the same.
4
FIs “Does a higher ramp make the car travel further?” a question that can be tested? Write yes or no.
5
FA pupil writes: “The heavier the car, the further it goes.” Is this a prediction or a conclusion? Write the word.
6
FIn a test on how sugar dissolves, the water is heated to different temperatures. Which variable is the independent variable? Write the word.
7
FIn the same sugar test, which variable is the dependent variable? Write the words.
8
PSMo tests whether the colour of a car changes how far it goes. Which variable is the independent variable? Write the words.
9
PSWrite a prediction for the ramp test in the form “If we ... then ... because ...”. Accept any prediction that uses the height, the distance and a reason.
10
PSWorking scientifically: name one thing you would observe to test your prediction in question 9. Accept any one observation of the car.
11
RExplain why the starting point of the car must be the same in every test. Write one sentence.
12
PSRuby says her test is fair because she changed the height and the car colour. Is she right? Write yes or no.
13
RChallenge: a pupil says the distance is caused by the height. Give one reason why we should be careful before we agree. Write one sentence.
1.2

Planning a fair test and managing risk

Year 7
WS1: plan enquiries and fair tests; WS2: assess risk and use apparatus safely
Video lesson: Planning a fair test and managing riskComing soon
Story. Omar is planning a practical with hot water. Before he starts, his teacher asks him to write a risk assessment. “Think about what could cause harm, how likely it is, and how you will stop it,” she says.

A hazard is something that could cause harm. A risk is the chance that harm will happen, and how serious it could be. A risk assessment names the hazards, the risks, and the control measures that reduce them.

A fair test is planned before practical work starts. Decide the independent variable, the dependent variable, how you will measure it, how many repeats you will do, and which control variables you will keep the same.

!hot water in a beaker!a sharp scalpel!a glass thermometer
Three hazards in a school lab. Each one needs a control measure.

The table shows three hazards from practical work and a control measure for each.

HazardHarm it could causeControl measure
hot water in a beakerscalds the skinuse tongs and a heatproof mat; wear eye protection
a sharp scalpelcuts the skincut away from your body; keep it on the bench
a glass thermometerbreaks and cutshold it by the top; never rest it on the bottom of a tank

Key ideas

  • A hazard is something that could cause harm.
  • A risk is the chance of harm happening, and how serious it could be.
  • Control measures reduce the risk, for example tongs, eye protection and a heatproof mat.
  • Plan the repeats and the control variables before the practical.
Worked example 1.2.1
What is the hazard when a beaker of hot water is used in a practical? Write the words.

Method. Find what could cause harm.

  1. Look at the apparatus. Hot water can cause a scald if it touches the skin.
    hot water
  2. Name the hazard. The hazard is the hot water in the beaker.
    hot water in a beaker
  3. Write the answer.
    hot water in a beaker

Check. The hazard is not the same as the risk. ✓

Worked example 1.2.2
Give one control measure for hot water in a beaker. Write one thing you would do.

Method. Think about how to keep your hands away from the water.

  1. Think about the contact. Tongs keep your hands away from the hot beaker.
    tongs
  2. Write the measure. Use tongs and a heatproof mat.
    use tongs
  3. Write the answer.
    Use tongs and a heatproof mat.

Check. Any sensible control measure that reduces contact is correct. ✓

Worked example 1.2.3
In a plan, the car is the same in every test, and the ramp height is 10 cm, 20 cm and 30 cm. How many heights are tested? Write the number.

Method. Count the heights in the plan.

  1. Count. The heights listed are 10 cm, 20 cm and 30 cm.
    10, 20, 30
  2. Write the number. So three heights are tested.
    3
  3. Write the answer.
    3

Check. Three heights, one number each. ✓

Watch out

Watch out: a risk assessment names the control measures for each hazard. Naming a hazard without a control measure is not a complete plan.

Exam tip

Exam tip. In a risk question, give the hazard and one control measure that reduces it.

Try it (with your teacher, or a grown-up at home). With your teacher, plan a fair test for a toy car on a ramp. Write the independent variable, the dependent variable, two control variables, and one hazard with its control measure. Ask your teacher to check your plan before you start.

Exercise 1B  Planning a fair test and managing risk

1
FWhat do we call something that could cause harm? Write the word.
2
FWhat do we call the chance that harm will happen, together with how serious it could be? Write the word.
3
FName one item of eye protection used in a school lab. Write one item.
4
FIs a glass beaker of hot water a hazard? Write yes or no.
5
FWrite the word for the things we do to reduce a risk, such as using tongs. Write the two words.
6
PSBen plans to test each ramp height once only. Give one reason why he should repeat each test. Write one sentence.
7
PSEllie plans to use a ramp with a different toy car in each height test. Is her plan fair? Write yes or no.
8
PSWhich of these is the best control measure for a sharp scalpel? Write the letter: A, B or C. A: hold it by the blade. B: cut away from your body. C: pass it blade first.
9
PSWorking scientifically: a pupil wants to heat a liquid in a test tube. Name one thing the risk assessment should say. Accept any one of the following: a control measure, a hazard, or who must supervise.
10
PSRuby writes “Use tongs” as the control measure for a hot beaker, and does not name the hazard. Is her risk assessment complete? Write yes or no.
11
RChallenge: explain why a pupil must follow a risk assessment even if the practical looks safe. Write one sentence.
1.3

Accuracy, precision, repeats and anomalies

Year 7
WS3: take measurements with accuracy and precision, repeating readings where needed; spot an anomaly
Video lesson: Accuracy, precision, repeats and anomaliesComing soon
Story. Ellie measures how far the toy car travels three times for each ramp height. For the 30 cm ramp, one trial is much larger than the others. “Is that wrong, or is it a real result?” she asks. Her teacher says, “Let us look at the data and decide.”

Precision is how close repeated readings are to each other. Accuracy is how close a reading is to the true value. A ruler marked in millimetres is more precise than one marked in centimetres.

Repeat each reading at least three times. The mean is the total divided by the number of readings. An anomaly is a result that does not fit the pattern, and it should be checked. A result can be left out of the mean only with a clear reason, such as a mistake in the measurement.

The range is the biggest reading minus the smallest. It is a simple measure of uncertainty: the readings spread across the range.

The table shows the three trials for each ramp height. The 150 cm trial for the 30 cm ramp is an anomaly.

Ramp height (cm)Trial 1 (cm)Trial 2 (cm)Trial 3 (cm)
10504852
20889290
30120126150

Key ideas

  • Precision: repeated readings close together.
  • The mean = total of the readings divided by how many readings.
  • An anomaly must be checked, and left out of the mean only with a reason.
  • The range = biggest reading minus smallest reading.
Worked example 1.3.1
Find the mean distance for the 10 cm ramp, using the three trials 50, 48 and 52. Write the number of centimetres.

Method. Add the trials, then divide by three.

  1. Add. The total is 50 + 48 + 52 = 150.
    150
  2. Divide. Divide the total by 3.
    150 / 3 = 50
  3. Write the answer.
    50 cm

Check. Three trials that add to 150 have a mean of 50. ✓

Worked example 1.3.2
The 30 cm ramp trials are 120, 126 and 150 cm. Which trial is the anomaly? Write the number of centimetres.

Method. Find the reading that does not fit the pattern.

  1. Compare. The 10 cm and 20 cm trials are close together, but 150 is much bigger than 120 and 126.
    much bigger
  2. Check. The check shows the trial did not fit, so it is the anomaly.
    anomaly
  3. Write the answer.
    150 cm

Check. The other two trials are close to each other. ✓

Worked example 1.3.3
For the 10 cm ramp, the trials are 50, 48 and 52. What is the range? Write the number of centimetres.

Method. Subtract the smallest reading from the biggest.

  1. Find the biggest. The biggest reading is 52 cm.
    52
  2. Find the smallest. The smallest reading is 48 cm.
    48
  3. Subtract. The range is 52 minus 48.
    52 - 48 = 4
  4. Write the answer.
    4 cm

Check. The readings lie within 2 cm either side of the mean of 50 cm. ✓

Watch out

Watch out: do not drop a reading just because it is inconvenient. Only leave an anomaly out when you can give a reason, and say so in your report.

Exam tip

Exam tip. When you find a mean, always show the total and the number you divided by.

Try it (with your teacher, or a grown-up at home). Roll a toy car down a ramp three times at the same height, and measure how far it goes each time with a ruler. Find the mean and the range. Do the three readings agree closely? Write down whether the result is precise.

Exercise 1C  Accuracy, precision, repeats and anomalies

1
FFind the mean of 88, 92 and 90 centimetres. Write the number of centimetres.
2
FWhat is the range of the 20 cm trials, 88, 92 and 90 cm? Write the number of centimetres.
3
FWhich 30 cm trial is the anomaly? Write the number of centimetres.
4
FWhich ruler gives a more precise reading: one marked in millimetres, or one marked in centimetres? Write the word: millimetres or centimetres.
5
FRepeating a measurement several times makes the results more what? Write one word.
6
PSFind the mean of the 30 cm trials, leaving out the anomaly. Write the number of centimetres.
7
PSFind the mean of all three 30 cm trials, including the anomaly. Write the number of centimetres.
8
PSBen says the 10 cm ramp always gives a distance of exactly 50 cm. Is Ben right? Write yes or no.
9
PSEllie's mean for the 10 cm ramp is 50 cm, and the range is 4 cm. Write the lowest and highest readings as a range, in centimetres, from lowest to highest.
10
PSA stopwatch that shows hundredths of a second is used instead of one that shows whole seconds. Is the stopwatch more precise? Write yes or no.
11
RExplain why a result should not be left out of a mean unless you have a reason. Write one sentence.
12
RChallenge: the 30 cm ramp was tested three times with a result of 150 cm for the third trial. Suggest one reason why this might be a mistake, and one way to check it. Write one sentence for each.
1.4

Recording and presenting data

Year 7
WS4: record and present data in tables, bar charts, line graphs and scatter graphs, with labels and units
Video lesson: Recording and presenting dataComing soon
Story. Mo has a table of results from the ramp test. His teacher asks him to show the means as a graph. “Which graph should I use?” he asks. She says, “Look at the kind of data first. Is the height a number that can be any value, or is it a group?”

Choose the graph from the type of data. Categoric data are groups, such as colours; they are shown in a bar chart, with a gap between the bars. Continuous data can take any value in a range; a scatter graph shows two sets of such values and can show a correlation. A line of best fit is a straight line drawn through the middle of the points.

Every graph needs a title, labelled axes with units, and an even scale.

020406080100120140mean distance (cm)5010 cm9020 cm12330 cmramp height (cm)
Bar chart of the mean distance for each ramp height.
010203040020406080100120140mean distance (cm)ramp height (cm)
Scatter graph of the mean distance against ramp height, with a line of best fit.

The table gives the mean distance for each height, with the anomaly left out of the 30 cm mean.

Ramp height (cm)Mean distance (cm)
1050
2090
30123

Key ideas

  • Categoric data (groups) go in a bar chart.
  • Continuous data go in a scatter graph or a line graph.
  • Put the independent variable on the horizontal axis.
  • Always label the axes with units, and give the graph a title.
Worked example 1.4.1
Mo counts the cars of each colour that went furthest. Which graph should he use? Write the words.

Method. Decide whether the data are groups.

  1. Look at the data. The colours are groups, not numbers on a continuous scale.
    groups
  2. Choose the graph. Groups of data are shown in a bar chart.
    bar chart
  3. Write the answer.
    bar chart

Check. A line of best fit is only for continuous data. ✓

Worked example 1.4.2
From the bar chart, what is the mean distance for the 20 cm ramp? Write the number of centimetres.

Method. Read the bar for 20 cm.

  1. Find the bar. The middle bar is for the 20 cm ramp.
    20 cm
  2. Read the top. The top of that bar is at 90 cm.
    90
  3. Write the answer.
    90 cm

Check. The table also gives 90 cm for 20 cm. ✓

Worked example 1.4.3
In a scatter graph, which variable goes on the horizontal axis? Write the words.

Method. Recall where the independent variable goes.

  1. Recall. The independent variable is the one we change, so it is plotted on the horizontal axis.
    horizontal
  2. Apply it. Here the ramp height is changed, so it goes on the horizontal axis.
    ramp height
  3. Write the answer.
    the ramp height

Check. The distance is plotted on the vertical axis. ✓

Watch out

Watch out: a bar chart has gaps between the bars. A scatter graph has points, and you may draw a line of best fit through them.

Exam tip

Exam tip. Every axis needs a label and a unit. Without units, a graph loses marks.

Try it (with your teacher, or a grown-up at home). Use a ruler to measure how far a toy car travels from three ramp heights, three times each. Draw a bar chart of the means, with labelled axes and a title. Then draw a scatter graph of the same means, and a line of best fit by eye.

Exercise 1D  Recording and presenting data

1
FWhich graph should be used to show the number of sweets of each colour in a packet? Write the words.
2
FWhich graph is used for data that can take any value, such as a measured height? Write the words.
3
FOn the bar chart, what is the mean distance for the 30 cm ramp? Write the number of centimetres.
4
FWhat should go on the horizontal axis of the scatter graph? Write the words.
5
FWrite the unit that should be on the vertical axis of the scatter graph. Write the unit.
6
FWhat does a title on a graph tell the reader? Write one sentence.
7
PSWhat is the difference between the mean distance for the 30 cm ramp and the 10 cm ramp? Write the number of centimetres.
8
PSEllie says the bar for 10 cm is the tallest bar on the chart. Is she right? Write yes or no.
9
PSWhat should the vertical axis label of the bar chart say? Write the label, with a unit.
10
PSA line of best fit is drawn through the points of a scatter graph. Give one reason it is drawn. Write one sentence.
11
PSWorking scientifically: Ruby records her results in a table with the height first, then the three trials. Give one improvement to the table. Write one sentence.
12
RChallenge: explain why a scatter graph is better than a bar chart for the means of the ramp heights when the heights are a measured value. Write one sentence.
1.5

Evaluating evidence, conclusions and models

Year 7
WS5: evaluate methods, evidence and conclusions; WS6: use models and evidence to support or refute ideas
Video lesson: Evaluating evidence, conclusions and modelsComing soon
Story. Ellie writes her conclusion: “A higher ramp makes the car go further.” Her teacher asks two questions: “Does your data support that? And what could make the test better next time?”

A conclusion must match the data. It should say what the data show, and it should not claim more than the data show. Evaluating a method means deciding what went well, what could be improved, and how much you can trust the result.

Scientists use models to explain observations, for example the particle model explains why gases spread out. A model is supported when the evidence fits it, and it is refuted when evidence does not fit. Ideas change when the evidence changes.

Key ideas

  • A conclusion matches the data and does not claim more.
  • Evaluation covers the method, the repeats, anomalies and the uncertainty.
  • Evidence supports an idea when it fits the idea, and refutes it when it does not.
  • Improvements should target the biggest weakness in the method.
Worked example 1.5.1
Ellie's means are 50 cm, 90 cm and 123 cm for 10 cm, 20 cm and 30 cm. Does this data support the conclusion that a higher ramp makes the car go further? Write yes or no.

Method. Check whether the mean rises as the height rises.

  1. Read the means. The mean goes up from 50 cm to 90 cm to 123 cm as the height goes up.
    goes up
  2. Decide. The data support the conclusion, so the answer is yes.
    yes
  3. Write the answer.
    yes

Check. The pattern holds for all three heights. ✓

Worked example 1.5.2
Name one way to improve Ellie's test. Write one improvement.

Method. Find the weakest part of the method.

  1. Look at the method. The 30 cm anomaly was left out, so more repeats would show if it happens again.
    more repeats
  2. Write the improvement. Repeat each height at least five times, and record any anomaly with a reason.
    five times
  3. Write the answer.
    Repeat each height at least five times, and record any anomaly with a reason.

Check. Any sensible improvement that addresses a weakness is correct. ✓

Worked example 1.5.3
The particle model says gas particles move around freely. A gas spreads out to fill a room. Does this support the model? Write yes or no.

Method. Check whether the observation fits the model.

  1. Read the observation. A gas spreads out to fill its container.
    spreads out
  2. Decide. Moving particles spread out to fill the space, so the observation fits the model.
    yes
  3. Write the answer.
    yes

Check. Evidence that fits a model supports it. ✓

Watch out

Watch out: a conclusion should say what the data show, not what you hoped for. Do not say “proves” when the test only shows a pattern.

Exam tip

Exam tip. In an evaluation, name one strength, one weakness and one improvement that would fix the weakness.

Try it (with your teacher, or a grown-up at home). Write a conclusion from your ramp results in one sentence, using the words “the data show”. Then write one thing that would make the test more reliable next time.

Exercise 1E  Evaluating evidence, conclusions and models

1
FAre the means 50 cm, 90 cm and 123 cm consistent with a higher ramp giving a longer distance? Write yes or no.
2
FWhat does a conclusion need to match? Write one word.
3
FName one weakness of testing each height only three times. Write one sentence.
4
FA gas spreads out to fill its container. Which model explains this best? Write the name of the model.
5
FEvidence fits an idea, so we say the evidence is what? Write one word: supports or refutes.
6
PSWhich is the best improvement to a ramp test: more repeats, or a different colour for the car? Write the words.
7
PSBen says his results prove that height causes distance. Is his claim stronger than the data allow? Write yes or no.
8
PSMo says the 30 cm mean of 123 cm is the true distance for every car. Give one reason he is not right. Write one sentence.
9
PSWorking scientifically: a pupil says the ramp test shows that friction is zero. Name one piece of evidence you would need to check this. Accept any one observation of friction.
10
RChallenge: explain why a scientific model can be changed when new evidence does not fit it. Write one sentence.

Chapter summary

SkillMethod
VariablesChange the independent variable, measure the dependent variable, keep the control variables the same.
RiskName the hazard and one control measure for each practical.
Repeats and meansRepeat at least three times. Mean = total divided by the number of readings.
Anomalies and rangeCheck an anomaly, and leave it out only with a reason. Range = biggest minus smallest.
GraphsBar chart for groups. Scatter graph for continuous data. Label axes with units.
EvaluationA conclusion must match the data. Evaluate the method, and name an improvement.

Can you…?

  • I can name the independent, dependent and control variables in a fair test
  • I can plan a fair test with a risk assessment
  • I can find a mean and a range from repeat readings
  • I can spot an anomaly and say why it may be left out
  • I can choose and draw a bar chart or a scatter graph with labels and units
  • I can write a conclusion that matches the data, and evaluate a method

Key terms

independent variable
the variable that we change on purpose
dependent variable
the variable that we measure; it depends on the independent variable
control variable
a variable that is kept the same so the test is fair
hazard
something that could cause harm
risk
the chance of harm happening, and how serious it could be
control measure
an action that reduces a risk
precision
how close repeated readings are to each other
accuracy
how close a reading is to the true value
anomaly
a result that does not fit the pattern of the others
range
the biggest reading minus the smallest reading
uncertainty
how much a result could vary; the spread of the readings
line of best fit
a straight line drawn through the middle of the points on a scatter graph

Exercise 1Z  Check-up

1
What is the independent variable in an experiment? Write the two words.
2
Find the mean of 10, 12 and 14. Write the number.
3
Name one control measure for a sharp scalpel. Write one control measure.
4
Which is the anomaly in the trials 40, 42, 41 and 90 cm? Write the number.
5
The range of the trials 40, 42 and 41 cm is what? Write the number of centimetres.
6
Which graph is best for showing the number of cars of each colour? Write the words.
7
What does a fair test change? Write the phrase: one variable or many variables.
8
A hazard is something that could cause harm. Write the word for the chance of harm, together with how serious it could be.
9
A pupil's test has a 10 cm ramp mean of 50 cm and a 20 cm ramp mean of 90 cm. By how much does the mean rise? Write the number of centimetres.
10
Explain why repeating a measurement helps a scientist. Write one sentence.

Total 16 marks. Allow about 16 minutes.

Exercise 1X  Practice test questions

1
PSA pupil's bar chart shows the mean for 10 cm as 50 cm and for 20 cm as 90 cm. Write the difference between the two means, in centimetres.[2 marks]
2
PSA class repeated a test three times and got the results 20 cm, 22 cm and 21 cm. Write the mean of these three results, in centimetres.[2 marks]
3
FName the variable that is measured in a test on how far a car travels. Write the two words.[1 mark]
4
FWrite one control variable for a test on how far a car travels down a ramp. Write one thing.[1 mark]
5
FGive the hazard and one control measure for a glass beaker of hot water. Write the hazard, then one control measure.[2 marks]
6
PSA pupil says the 10 cm trial mean is 50 cm, so every trial at 10 cm is exactly 50 cm. Is the pupil right? Write yes or no, and give the reason in one word.[2 marks]
7
FWrite the type of graph used for data that can take any value, such as a measured distance. Write the words.[1 mark]
8
RGive one reason why a pupil should leave out an anomaly from a mean. Write one sentence.[2 marks]
9
RName one conclusion that the ramp data support. Write one sentence.[2 marks]
10
FWrite the unit that must be on each axis of a graph of mean distance against ramp height, for the distance axis. Write the unit.[1 mark]
Chapter 2: Cells and microscopes →

Want a tutor to go through this chapter with your child?

Same tutor, same time, every week, live online. The first session is a free introduction.

💬 Book a Free Intro on WhatsApp
Chat on WhatsApp