Plants and Water

How Do Plants Release Water: Transpiration Experiment

Max. D Gray
By Max. D Gray. Updated: January 16, 2017
How Do Plants Release Water: Transpiration Experiment

All plants - from weeds to the tallest of trees - need water to live and grow. They obtain water through their roots, which is then absorbed through the stems until it reaches and nourishes the entire plant. However, you might not know that plants also expel water through their leaves. This cannot be seen with the naked eye, since the droplets are so small.

If you want to learn how do plants release water, try out this OneHowTo experiment. It's easy, fun, and you'll learn a lot with your family and friends when you finally see how this happens with your own eyes. Read on!

You'll need:

  • Plastic bag
  • String
  • A plant
You may also be interested in: How to Plant Succulents in Containers

Steps to follow:


First of all, choose a plant from your home or school. The bigger the plant, the better, since it should have branches. It's better if it's a shrub or a small tree in a sunny location.

Once you've picked the plant you'll experiment on, place a plastic bag on a small branch with leaves. Leave the plastic bag around the branch for two or three days. This has to replicate what is shown in the image.

Make sure that it's properly tied, since strong winds might rip it out! This might sound obvious, but if you're doing this experiment on a shared space you should tell your neighbors or classmates - otherwise, they might take the bag off by mistake.

How Do Plants Release Water: Transpiration Experiment - Step 1

Once you've done that, pay close attention to the plant for a few days and water it as you would normally. A good scientist doesn't forget about their experiments!

If you watch the bag, you'll see how drops of water are gathered inside, and how the plastic gets misty. If the days are very hot, lots of water will accumulate inside the bag.

How Do Plants Release Water: Transpiration Experiment - Step 2

Why does water appear in the plastic bag?

Want to know what happened? Plants release water through very small holes throughout the surface of their leaves. With heat - especially on the hottest days - droplets of water are expelled through these holes and evaporate. This is where the water accumulated inside the bag comes from.


Why do plants release water, then?

It's part of their nourishing process; water is absorbed from the soil, but excess water has to be expelled. This process is called transpiration - yes, like in humans. When this process is described along with evaporation - what happens on the leaves - it's called evapotranspiration. Plants can also release water when injured, but that's a different process.

Evapotranspiration rates change depending on environmental factors such as weather, humidity, or soil type. This process is actually very important, since it brings a good 10% of the water in the atmosphere of our planet.


Now that you know how do plants release water, try the transpiration experiment to confirm it!

If you want to read similar articles to How Do Plants Release Water: Transpiration Experiment, we recommend you visit our Hobbies & Science category.

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How Do Plants Release Water: Transpiration Experiment