Effect on temperature on the rate of transpiration of HIbiscus sp

Variables

Independent variable: Soil temperature

Dependent variables: Rate of transpiration of Hibiscus sp

Controlled variables: - Type of plant

      - Size of plant specimen

    - Light intensity

    - Humidity

    - Wind speed

    - Amount of water

    - Type of potometer

    - Time

ASPECT 2

Controlling variables

Plant

Use the same type of plant for every experiment and cut them into the same size.

Humidity, wind speed

The results wouldn’t have much effect even though humidity and wind speed isn’t controlled, since the plant specimen is placed in since water. Still, to have a more accurate result, experiments should be done in the same environment and the temperature outside should be kept constant.

Light intensity

Use the same light bulb and keep the distance between the light and the photometer constant in all the experiments.

Potometer

Use the same potometer in order to prevent any anomalies. Moreover, the water syringe and the tube placed in the potometer should also be the same, so the volume of the water can be kept constant.

Time

The time to equilibrate and the time in measuring the air bubbles should be the same for all the experiments.

Materials

- Potometer

- Plant specimen

- Incubator

- Stopwatch

- Ruler

- Water

Procedure

1. Make sure experimenters use the same room during the experiment, in order to have a constant wind speed and humidity. Keep the distance of the light and the potometer stable throughout the experiment. Ensure that the size and the type of light bulb used is the same for all the experiment.

2. Heat water in the incubator to 5°C.

3. Immerse the syringe and potometer tube in a sink, ensuring that both are full of water. Make sure that the estimate of the water filled is almost the same in all the experiment.

4. Cut the 2cm of plant specimen and place the specimen right away into the tube.
5. Pull the syringe and adjust the air bubble to 0.

6. Wait for about 1 minute and allow it to equilibrate.

7. Measure the distance moved by the air bubble along the scale on the potometer in 1 minute and collect data.

8. Record the quantitative and the qualitative raw data in the table shown below.

9. Repeat steps 1 to 8 two times in order to reduce any anomalies.

10. Repeat steps 1 to 9, changing the water temperature in the incubator to 15°C, 25°C, 35°C and 45°C. Ensure that all the other variables are kept constant

ASPECT 3

Data Collection

The effect of temperature on the rate of transpiration of Hibiscus sp

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