Video transcript
Hi I'm Emily and I'm a teacher at the Field of Mars Environmental Education Centre. I'll be showing you how to measure some atmospheric abiotic factors, such as wind speed, temperature, relative humidity and light intensity.
Your investigation requires you to select correct equipment that ensures a valid test to provide reliable data. To measure the abiotic factors today we'll be using the Kestrel 3000 which can measure air temperature, wind speed and relative humidity. And a light meter to measure light intensity.
Let's hang the Kestrel 3000 on a branch nearby so it can equilibrate with the surrounding temperature, that takes about two minutes. In the meantime I'll show you how to use the light meter. There's a meter and a sensor. Turn the meter on until you reach the setting of times 100. You need to take the cap off the light sensor and then hold it out from your body pointing up towards the sky. The reading will give you a measurement in lux; don't forget to multiply it by 100 to get the correct reading. Because the light can vary in different parts of the forest you'll want to take an average of a few readings to ensure that your data is reliable. When you've finished put the cap on the sensor and turn the meter off.
Now it's time to measure the other abiotic factors. Press the middle button to turn on the Kestrel 3000. We're going to use the anenometer setting to work out wind speed. Press the right arrow until you see a puff of wind symbol in the bottom of the screen. Work out the direction of the wind speed and point the anenometer into the direction of the wind. Take a measurement of the maximum wind speed in kilometers per hour. It's really important when you use this instrument that you hold it on the outer edges so that you don't interfere with any of the readings.
Next we're going to measure air temperature so press the right-hand button again until you get a picture of a thermometer in the screen. Hold it away from your body with your hands on the side. Today's reading is twenty-five point five degrees Celsius.
And finally we're going to measure relative humidity. So press the right arrow again until you get the hygrometer symbol which looks like this. About a meter from the ground and you will have your percentage relative humidity reading. That's it for now, you're finished. So push the button in the middle and turn off the Kestrel 3000, slide it back into its case.
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Listen now to the story of an urban catchment. A man at the top of the hill decided to cut down a tree and the tree loppers chopped it up into woodchip. It rained and some of the woodchip washed into the creek. Also because the tree had been holding the soil together with its roots. Now there was a lot of loose topsoil and dirt washed into the creek. Further downstream a lady was painting her house and when she finished she washed the brushes under the hose and tipped the bucket into the gutter. Next door a man was washing his car on the road instead of on the grass and detergent got hosed into the drains.
Further down the road a household of five was having trouble with their plumbing. It was an old house and tree roots had cracked the sewer pipe and toilet paper was washing down the gutter with the overflow. As the water continued its journey down through the catchment it collected all sorts of debris. Old band-aids, tea bags, a plastic bag and a plastic bottle. Is anyone thirsty?
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