Biophysical factors include temperature, soil type and vegetation type. On excursion, we measure and observe factors relating to:
atmosphere
lithosphere
biosphere
All of these factors influence the geomorphic processes and therefore landscapes and landforms of an environment.
Geographical tools are used to measure various factors. View images and descriptions of some geographical tools students use on excursions.
Thermometer
We use a glass thermometer to measure air temperature:
hold the thermometer about 1m above ground and away from your body
wait for a minute or two
read the measurement off the scale.
Anemometer
We use a digital anemometer to measure wind speed:
hold the meter up high into the wind so that the wind blows the fan for one minute
record the maximum wind speed from over the minute.
Hygrometer
Humidity measures the amount of moisture in the air, as a percentage. We use a digital hygrometer to measure humidity:
set the meter on the ground
leave it still for a few minutes
read the percent humidity.
Compass
Aspect is the direction that an environment faces:
rotate so that so that you are looking downhill from the study site (hint: face the direction a ball or dropped Maltesers would roll)
hold a compass level (horizontal) in your hand
read and record the direction you are facing, e.g. north or southwest.
Clinometer
Slope measures the steepness of the environment. We use a clinometer to measure slope. It measures angles similar to a protractor. As the environment is usually uneven, we take an average slope:
send a classmate that is a similar height to the other end of the environment
hold the clinometer steady and aim from your eye level to their eye level
press the trigger - the pointer is free to swing and will point down due to gravity
once the pointer stops swinging, release the trigger to lock it in place
read the angle off the scale.
On Monday 18 May 2020, two of our teachers went to Wattamolla to measure some biophysical factors at approximately 2pm. Look at the photo and map of the study site. How far of a walk is it from Wattamolla picnic area to the study site?
Download the Biophysical factors worksheet. Complete the table using the measurements and observations shown and described in the photos below.
Soil feels gritty.
Soil cannot form a ball, therefore sandy.
Soil feels wet.
The main vegetation type around Wattamolla is heath.
This blackened plant is evidence of recent bushfire in January 2018.
The Bureau of Meteorology is the Australian Government's official weather forecaster. They built an automatic weather station near Providential Headland on the top of a cliff. It measures wind direction and wind speed every 30 minutes. It takes extra measurements when there is a strong gust or change (of direction). All of the data is recorded on the Bureau's website.
Look at the climate graph showing the mean (average) wind speed at Wattamolla:
What is the mean wind speed for May?
Compare the reading you recording from the anemometer to the mean wind speed for May:
Are they similar or different? Explain why they may be different.
Download or print another copy of the biophysical factors worksheet. Complete as many of the measurements as possible based on the resources you have at school or at home. We have provided some suggestions.
Compare to the measurements at Wattamolla.
If you do not have a thermometer, get a reading from your nearest Bureau of Meteorology weather station or mobile phone weather app. Why isn't this as accurate as using a thermometer?
Build your own anemometer or use the Beaufort wind scale to estimate wind speed.
If you cannot access a hygrometer, then make your own observation. Choose from: very dry, dry, average, humid, very humid.
Your teacher should be able to help you with this one. If you're in Sydney it is likely sandstone.
Rub a bit of the soil on paper to observe its colour. Make your own observations about texture and moisture. Use the soil chart for soil type.
If you don't have a compass, use a compass app on a smartphone. The Arduino Science Journal app comes with one.
Use the vegetation classification charts and the Picture key to the structural forms of Australian vegetation to identify any native vegetation near your study site.
Can you see any fire evidence? Look up or ask about the most recent bushfires near your study site.