⬇️ Do roots grow down even if you turn the seed?

My hypothesis

If I change how the beans are turned on day three, then how many of the three roots in a bag have their tips pointing down on day seven will ______, because ______.

🔊 You fill in the blanks. Think about what a root is for, and how its very tip could sense which way to grow. 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

• 🫘 Dried beans from the grocery bag (pinto, lima or kidney): 27, all the same kind
• 🥣 A big bowl: 1, for soaking
• 🛍️ Plastic bags: 9 zip bags
• 🧻 Paper towels
• 📦 Flat cardboard: 3 pieces, bigger than three bags side by side
• 🚰 Water from the tap
• 🩹 Masking tape, to mark lines
• 🖍️ Crayons or markers

Steps

1. Soak 27 beans in a big bowl of water overnight.🔊
2. Fold a damp paper towel to fit inside each of nine zip bags.🔊
3. Slide three beans between the towel and the front of each bag, spaced out in a row.🔊
4. Zip each bag almost shut, and tape three bags onto each piece of cardboard.🔊
5. Label the boards never, quarter and upside down, and stand them against a wall in one warm room.🔊
6. Every day, add a few drops of water to any dry towel, and tell a grown-up if a bag smells bad.🔊
7. On day three, check that every bean has a short root.🔊
8. Leave the first board as it is, turn the second a quarter turn, and turn the third upside down.🔊
9. Stand the boards up again, and watch the roots each day.🔊
10. On day seven, count the roots in each bag with their tips pointing down, and write it in your table.🔊
11. Find the mean count for each way of turning and draw a bar graph.🔊
12. Wash your hands after touching the beans, and never eat them.🔊

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 bar graph, one bar for each thing you tried.

Why it works

🔊 Roots can feel which way is down. Tiny heavy grains in a root's tip sink to the low side of its cells, and that tells the root which way to bend. So when you turn the seed, the root usually curves round until its tip points down again, which helps the plant hold on and find water.

Going further (7th and up): Change a second thing: count the bent roots after one, two and three days since the turn, and draw a line of how many point down each day.

Board layout

This project at your grade

From 4th grade up, the table gets a mean column. See every project for 3rd grade, or print a blank results table.

What a judge will ask

• What did you change, and what did you measure? I changed how the beans are turned on day three and measured how many of the three roots in a bag have their tips pointing down on day seven, in roots pointing down, of 3.
• What did you keep the same, and why does that matter? I kept the same kind of bean, soaked overnight and three beans and a damp towel in every bag the same, so the only difference was how the beans are turned on day three.
• 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 count the bent roots after one, two and three days since the turn, and draw a line of how many point down each day.

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

• 🌱 Do beans grow best in soil, sand or cotton?2nd–6th grade · 14 days of testing · about $3🌦️ Growing and weather · 🌱 Outside and plants
• 🌱 Do plants bend toward the window?1st–5th grade · 12 days of testing · free🌦️ Growing and weather · 🌱 Outside and plants