🌿 Do Plants Sweat?

Wrap a clear bag around plant leaves and watch water droplets appear — proof that plants release water vapour into the air!

Easy⏱ Half dayAges 5+Biology
Do Plants Sweat?Transpiration!Water dropletscondense on bagAfter 2–3 hours in sun: droplets appear!

🧰 What you need

🌿
Healthy plant or leafy branch
1
🛍️
Clear plastic bag
1 sandwich-sized or larger
🔵
Rubber band or string
☀️
Sunny spot

🔬 Steps

  1. 1

    Choose a healthy leafy branch or plant. In the morning, put the clear plastic bag over several leaves.

  2. 2

    Secure the bag tightly around the stem/branch with a rubber band — make sure it's sealed.

    💡 The tighter the seal, the more you'll see — any gap lets vapour escape.
  3. 3

    Place the plant in a sunny spot for 2–3 hours.

    💡 More sunlight = more transpiration = more water droplets. A very sunny spot works best.
  4. 4

    After 2–3 hours, look at the inside of the bag — you should see water droplets or condensation!

🧠 The Science

Plants absorb water from the soil through their roots. This water travels up through the stem and into the leaves. In leaves, water exits through tiny pores called stomata (mostly on the underside of leaves). The water escapes as water vapour — this is called transpiration. A single tree can transpire hundreds of litres of water per day! The trapped water vapour condenses on the cooler bag surface into droplets you can see. Forests are important for the water cycle partly because trees transpire huge amounts of water into the atmosphere.

📚 Related Lessons

  • 🍃 Leaves and RootsLeaves make food using sunlight and roots drink water from soil — together they keep the plant alive!
  • 🌴 Plants in HabitatsPlants have amazing adaptations — cacti store water in deserts, lotus floats in ponds, and pine trees shed snow!
  • 🔄 Water CycleWater evaporates from oceans, rises as vapour, forms clouds through condensation, and falls as rain — endlessly!
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