🌈 Does a wider paper strip walk water faster?

My hypothesis

If I change how wide the paper towel strip is, then how high the colour climbs up the strip in five minutes will ______, because ______.

🔊 You fill in the blanks. Think about the tiny gaps in the paper, and whether a wider strip has bigger gaps or just more of them. A guess is a good because: the test finds out.

Change, measure, keep the same

Scientists call the thing you change the independent variable and the thing you measure the dependent variable. The things you keep the same are the controls: if one of them changed too, you wouldn't know which change made the difference. Try each of the 3 levels 3 times.

What you need

• 🧻 Paper towels: 2 sheets
• 🌈 Food colouring: one dark colour
• 🚰 Water from the tap
• 🫙 A clear jar or tall glass: a tall glass
• ✏️ A pencil
• ⏱️ A stopwatch or a kitchen timer
• 🖍️ Crayons or markers
• ✂️ Kid scissors
• 📏 A ruler
• 🩹 Tape

Steps

1. Pour water into a tall glass and stir in lots of food colouring.🔊
2. Cut nine strips 12 cm long: three 1 cm wide, three 3 cm wide and three 6 cm wide.🔊
3. Write each strip's width at its top with a crayon.🔊
4. Tape the top of a 1 cm strip to a pencil laid across the glass.🔊
5. Add or pour out water until the bottom 1 cm of the strip dips in, then start the timer.🔊
6. After five minutes, lift the strip out and lay it flat.🔊
7. Measure from the bottom of the strip up to where the colour stops, and write it in your table.🔊
8. Test the other widths the same way, with a new strip every time.🔊
9. Do all three widths two more times, then draw a line graph with width along the bottom.🔊

Every step is one you can do yourself, with a grown-up nearby. Write each number down straight away, in the table below, so nothing is lost.

Your results table

From 4th grade, add the tries for each level and divide by how many there were: that's the mean, and it goes in the last column. Then draw a line graph, because the thing you change is a number that goes up.

Why it works

🔊 A paper towel is made of tiny fibres with gaps between them. Water clings to the fibres and climbs through the gaps, which is called capillary action. How high it climbs depends on the size of the gaps, so strips of different widths may climb about the same height, but a wider strip carries more water.

Going further (7th and up): Change a second thing: cut the strips from a coffee filter as well, and graph the climb for each kind of paper at each width.

Board layout

This project at your grade

From 4th grade up, the table gets a mean column. See every project for 2nd grade, or print a blank results table.

What a judge will ask

• What did you change, and what did you measure? I changed how wide the paper towel strip is and measured how high the colour climbs up the strip in five minutes, in cm.
• What did you keep the same, and why does that matter? I kept strips cut from the same paper towel and the same strip length the same, so the only difference was how wide the paper towel strip is.
• How many times did you test it? 3 times at each of my 3 levels.
• If you did it again, what would you change or test next? I'd cut the strips from a coffee filter as well, and graph the climb for each kind of paper at each width.

Make it yours

Keep this project on this device and Peabody counts down to your fair day, with a plan for each day. Nothing is sent anywhere.

Try next

• 📄 Which paper pulls water up the highest?2nd–6th grade · 1 day of testing · about $1🧪 Water, ice and mixing · 🧂 Kitchen things
• 🥬 Do leaves help celery pull up coloured water?3rd–8th grade · 1 day of testing · about $2🧪 Water, ice and mixing · 🧂 Kitchen things

🔨 From the Workshop: this project grows from a Workshop build, with picture steps of its own.