🍃 Do leaves give off more water in sun or shade?

My hypothesis

If I change how much sun the leaves get, then how many drops of water collect in the bag in three hours will ______, because ______.

🔊 You fill in the blanks. Think about what leaves need the sun for, and what comes out of them while they work. 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

• 🌿 A leafy bush or tree outside, or a big potted plant: a bush or tree with branches in sun and in shade
• 🛍️ Plastic bags: 9 clear ones, big enough to cover a leafy branch
• ➰ Rubber bands: 9
• 🩹 Masking tape, to mark lines
• 🖍️ Crayons or markers
• 🥛 Clear plastic cups, all the same size: 9
• 💧 An eyedropper or a medicine dropper

Steps

1. With a grown-up, pick a bush or tree that has branches in full sun, part shade and full shade.🔊
2. Write sun, part or shade on a bit of masking tape, three of each, and stick one on each bag.🔊
3. Choose nine leafy branches that are still on the plant, three in each spot, with about the same leaves.🔊
4. Slip a clear bag over each branch and close its mouth around the stem with a rubber band, not too tight.🔊
5. Write down the time, and never look at the sun while you work.🔊
6. Leave the bags on for three hours on a dry day.🔊
7. Slide each bag off its branch for good and pour its water into its own clear cup.🔊
8. Draw up each cup's water with the dropper and count the drops as you squeeze them back out.🔊
9. Write each count in your results table.🔊
10. Find the mean drops for each spot and draw a bar graph.🔊
11. Wash your hands after touching the plants.🔊

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

🔊 Leaves have tiny holes that open to let air in so the plant can make food, and water vapour escapes through them too. In bright, warm light the holes are usually open and the warm air pulls out more vapour, so a bag in the sun often collects more. The vapour cools against the plastic and turns back into drops you can count.

Going further (7th and up): Change a second thing: bag a thin-leaved plant and a thick, waxy-leaved plant in the same spot, and graph the drops for each.

Board layout

This project at your grade

Every grade this project fits works out a mean. See every project for 4th grade, or print a blank results table.

What a judge will ask

• What did you change, and what did you measure? I changed how much sun the leaves get and measured how many drops of water collect in the bag in three hours, in drops.
• What did you keep the same, and why does that matter? I kept the same kind of plant, with about the same number of leaves in each bag and bags of the same size the same, so the only difference was how much sun the leaves get.
• 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 bag a thin-leaved plant and a thick, waxy-leaved plant in the same spot, and graph the drops for each.

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

• ☀️ Where does a puddle dry fastest: sun, shade or wind?2nd–6th grade · 2 days of testing · free🌦️ Growing and weather · 🌱 Outside and plants
• 🥤 Does a colder cup get more drops on its outside?3rd–7th grade · 1 day of testing · free🌦️ Growing and weather · 🧂 Kitchen things