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Botany Science Fair Project

Transpiration Rates Across Six Plants

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Transpiration Rates Across Six Plants | Science Fair Projects | STEM Projects
Which plant releases the most water vapor through its leaves? You build a plastic bubble around each of six different plants to trap the moisture they give off. This process is called transpiration (water loss through the plant surface). Each plant gets equal water and sunlight for seven days. The coleus plant released the most moisture at 71.7 mL. The strawberry plant came second at 60.8 mL. The tomato plant placed third at 56.4 mL despite having the largest leaf surface area. Lettuce released the least at only 18.5 mL.

Hypothesis

The hypothesis is that the tomato plant will transpire at the greatest rate.

Science Concepts Learned

Transpiration

Which plant releases the most moisture through its leaves? To find out, you build a plastic bubble around each of six different plants, trapping the water vapor they give off. Each plant gets equal water and sunlight for seven days. When the time is up, the coleus plant has released the most moisture at 71.7 mL. The strawberry plant comes second at 60.8 mL. The tomato plant places third at 56.4 mL — despite having the largest leaf surface area. Lettuce releases the least, at only 18.5 mL.

Method & Materials

You will measure the transpiration given off from each individual plant by constructing a plastic bubble to fit around the plant to catch and withhold the transpired water vapor. Each plant will be given equal amounts of water and sunlight.
You will need six plants, a plastic bubble, water, and sunlight.

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Results

The data recorded did not support the hypothesis of this experiment. The collia plant released the largest amount of water vapor, followed by the strawberry plant, the tomato, the four-o'clock, the black-eyed susan, and last the lettuce.

Why do this project?

This science project is interesting because it shows how different plants can have different rates of transpiration.

Also Consider

Experiment variations to consider include testing different types of plants or testing the plants in different climates.

Full project details

Additional information and source material for this project are available below.

Related video

These videos explain the science behind this project and demonstrate key concepts used in the experiment.
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