Planning a data collection – sensors

Hints and tips for collecting data:

  • When collecting humidity data you should also collect temperature data from the same place at the same time. Temperature change has a big impact on relative humidity, so your data analysis needs to allow for  this.
  • If you are investigating the effect of plant transpiration on humidity, you need to take account of other variables such as light and wind speed in your experiment. One method is to set a plant up in a controlled environment where these variables have less effect. An alternative is to collect your data over a longer time period in the natural environment and then analyse the data to look for patterns in different variables. Both methods have their limitations, so how about comparing these two approaches as a further investigation?
  • Your sensors need to be connected to a data logger if data is to be recorded. The logger needs to be sited somewhere safe, protected from weather and interference, and it needs a power supply. In your initial investigations you will be limited to where you can collect data by the length of the cable that connects the sensor to the logger. The logger can be placed inside on a convenient window ledge and the sensor cables passed through an open window to the outside. Remember that the window should not be left open when unattended.
  • When studying microclimate keep the sensors shaded from direct sunlight. This avoids ‘spikes’ in your data. Placing the sensors on the underside of branches or leaves is better than placing them on top. Zip ties, elastic bands and tape are all useful for holding sensors in place. Take care to keep  the sensor  clean as it is a sensitive instrument.
  • In this project different groups may want to use your data for comparison with their own. If possible label your data logger  with a name that is easily identified by others, and use this name on the Exploratory so that your data is labelled with your school, class and group name.