PicoScope 7 Software
Available on Windows, Mac and Linux
High speed and high resolution. Breakthrough ADC technology switches from 8 to 16 bits in the same oscilloscope.
Transpiration is the evaporation of water into the atmosphere from the leaves and stems of plants. Plants absorb water through their roots. This water can come from deep in the soil. In the desert plants roots can penetrate as deep as 20 meters underground.
This is a simple experiment to prove that water is evaporating from the plant.
The apparatus is set up as shown in the photo. The humidity and temperature sensors are connected to the DrDAQ data logger, which is turn is plugged into the PC.
One branch of the plant, the humidity sensor and the temperature sensor are placed into the polythene bag and the end tied up with string.
PicoLog is set to record at one sample per second, with a maximum of 1200 samples (i.e. 20 minutes worth of data). The graph is set to show humidity. The spreadsheet is set to show both humidity and temperature.
Once the experiment is setup, leave the humidity sensor to log data for approximately 20 minutes. The temperature sensor is there to prove the temperature is kept constant.
Further study could involve comparing the transpiration of a control leaf to one smeared in petroleum jelly.