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Class 6 · Science and environment

Which paper towel soaks up most? A fair test

Which paper soaks up the most water: kitchen towel, tissue or newspaper? How can you make the test fair?

What you will learn: Plan a fair test by changing one variable and keeping others the same.

Small test at the end: scroll down to the end of this page for five short questions that check what you have learnt. Tap an answer, then press Check answer. Go to the questions ↓

Jump to: Check yourself · For grown-ups · For teachers

Safety first

A grown-up does any cutting. Wipe spills.

Keep it safe:

  • A grown-up cuts the paper squares if scissors are needed.
  • Wipe spills at once.

You will need

  • Three kinds of paperKitchen towel, tissue, newspaper, or any three.
  • A ruler and pencilTo mark 10 cm squares.
  • A measuring cup or syringe marked in mL
  • Three small bowlsAll the same size and shape.
  • A clock with seconds

Time: About 45 minutes.

The story

Tanmay knocks over a glass of water on Dadi's counter. Tara grabs a tissue, Tanmay grabs a newspaper and Dhruv grabs kitchen towel. "Mine soaks up the most!" they all shout at once. How could they test which paper really soaks up most, in a way nobody can argue with?

The idea

In a fair test, you change one thing on purpose. This is the independent variable: here, the type of paper.

You measure one thing to see the effect. This is the dependent variable: here, how much water is soaked up, in mL.

Everything else stays the same. These are the control variables: the size of the paper, the amount of water, how long it is dipped, and the same size and shape of bowl.

Soaked up = water at the start − water left.

A results table. Each 10 centimetre square was dipped in 50 millilitres of water for 10 seconds. Kitchen towel left 32 millilitres, so it soaked up 18. Tissue left 38, so it soaked up 12. Newspaper left 44, so it soaked up 6.10 cm squares, 50 mL water, 10 s dipPaperWater leftSoaked upKitchen towel32 mL18 mLTissue38 mL12 mLNewspaper44 mL6 mL
A results table. Each 10 centimetre square was dipped in 50 millilitres of water for 10 seconds. Kitchen towel left 32 millilitres, so it soaked up 18. Tissue left 38, so it soaked up 12. Newspaper left 44, so it soaked up 6.

Worked example

Priya's paper test

  1. Change: type of paper. Measure: water soaked up. Keep the same: 10 cm square, 50 mL of water, 10 seconds.
  2. Kitchen towel: 50 − 32 = 18 mL soaked up.
  3. Tissue: 50 − 38 = 12 mL.
  4. Newspaper: 50 − 44 = 6 mL.

In her test the kitchen towel soaked up the most: three times as much as newspaper.

Try it

  1. Plan.

    Write the three variables: what you change, what you measure, what you keep the same.

  2. Prepare.

    Mark and cut a 10 cm square of each paper.

    Put exactly 50 mL of water in each bowl.

  3. Test.

    Dip one square for 10 seconds, lift it out and let it drip over the bowl for 5 seconds.

  4. Measure.

    Pour the water left back into the measuring cup and read it.

    Soaked up = 50 − water left.

  5. Repeat for each paper.

    Same size, same water, same time.

  6. Conclude.

    Which soaked up most in your test? By how much?

What you make (paper or offline)

Your fair-test plan and results

A results table of water soaked up by three kinds of paper.10 cm squares, 50 mL water, 10 s dipPaperWater leftSoaked upKitchen towel32 mL18 mLTissue38 mL12 mLNewspaper44 mL6 mL
A results table of water soaked up by three kinds of paper.

Your three kinds of variable, written out.

A results table with water left and water soaked up.

A conclusion with numbers.

Make it on paper. Keep it with you. Nothing to upload.

Check yourself

Five questions about what this page teaches. Choose an answer and press Check answer, or open "See the answer and why". Nothing is saved or sent: your choices stay on this screen and disappear when you leave or reload the page.

  1. Question 1 of 5In the paper test, what is the independent variable (the thing you change on purpose)?

    See the answer and why
    • A. The 10 seconds of dipping Not this one. The time is kept the same: a control variable.
    • B. The amount of water soaked up Not this one. That is what you measure: the dependent variable.
    • C. The size of each square Not this one. Size is kept the same: a control variable.
    • D. The type of paper Correct. That is the one thing changed on purpose.
  2. Question 2 of 5What is the dependent variable (the thing you measure)?

    See the answer and why
    • A. The type of paper being tested Not this one. That is what you change, not what you measure.
    • B. The size of the bowl Not this one. The bowl is not what you measure. Use the same size and shape of bowl for every paper, because a different bowl could change how the paper is dipped.
    • C. Who does the dipping Not this one. The same person should do it. It is not what you measure.
    • D. The water soaked up, in mL Correct. You measure it to see what effect the paper type has.
  3. Question 3 of 5A paper started with 50 mL of water and left 35 mL. How much did it soak up?

    See the answer and why
    • A. 50 mL Not this one. 50 mL is what was there at the start.
    • B. 35 mL Not this one. 35 mL is what was left, not what was soaked up.
    • C. 15 mL Correct. 50 − 35 = 15 mL.
    • D. 85 mL Not this one. That adds them. Soaked up = start − left.
  4. Question 4 of 5Why must all the squares be the same size?

    See the answer and why
    • A. So they fit on one page of your book Not this one. Fitting on a page is not the reason. A fair test is.
    • B. Because paper only comes in 10 cm squares Not this one. You cut them to 10 cm on purpose, to keep size the same.
    • C. A bigger square could soak up more just because it is bigger Correct. Then you would not know whether size or paper type caused the difference.
    • D. So the test finishes quicker Not this one. Speed is not the reason. Fairness is.
  5. Question 5 of 5Ravi dipped the tissue for 10 seconds and the newspaper for 30 seconds. What is wrong?

    See the answer and why
    • A. Newspaper should always be dipped longest Not this one. Every paper must get the same time for a fair test.
    • B. He changed two things, so the test is not fair Correct. Paper type and time both changed, so you cannot tell which caused the difference.
    • C. He should not have used a clock Not this one. A clock is needed to keep the time the same.
    • D. Nothing, because longer is more accurate Not this one. Longer is fine only if every paper gets the same time.

Think back

Which control variable was hardest to keep the same?

Would you get the same order if you repeated the test?

Investigate further

  • Repeat each paper three times and find the average.
  • Test cloths: cotton, polyester and wool. Predict first.

For grown-upsTap a heading to open it. The safety notes are at the top of the page.

Before you start
  • Three kinds of paper, a measuring cup marked in mL, bowls, a clock.
  • Cut the squares if scissors are needed.
Questions that help
  • "What are you changing? What are you measuring? What stays the same?"
  • "How would it change the result if one square was bigger?"
What's really going on

Naming the independent, dependent and control variables is the core of planning an investigation, in school science and in real research.

Small differences of 1 or 2 mL may just be measuring error; repeats help show whether a difference is real.

Other ways to do it
  • No measuring cup? Count spoonfuls of water left, using the same spoon.

For teachersLearning aims, classroom ideas and what to look for.

Learning aims
  • Identify independent, dependent and control variables.
  • Plan and carry out a fair test with measurements.
Subject links
  • Science: materials and fair testing.
  • Mathematics: subtraction and measuring volume.

These links are general. They have not been checked against a specific board syllabus.

In the classroom
  • Groups test different papers; pool results in one class table and discuss differences between groups.
What to look for
  • All three kinds of variable named correctly.
  • Same size, water and time for every paper.
ProLearners Assist