Research methods: Abiotic factors Flashcards
what abiotic factors can be measured using electronic meters?
temperature
pH
dissolved oxygen
light level
wind or water velocity
What must be done to make sure electronic meters are accurate?
must be calibrated by adjusting its reading to be the same as a meter that is known to be accurate
what should be done if a meter cannot be calibrated?
percentage error should be noted so results can be adjusted
what can be used to measure light intensity?
a calibrated light meter
how can a light meter be standardised?
the same person holds it at the same height
or use a meter stick
what 2 methods for measuring humidity are there?
whirling hygrometer
electronic humidity meter
what is a whirling hygrometer?
traditional method for measuring humidity
how does a whirling hygrometer work?
uses two thermometers, one being dry and the other is kept wet
when spun the wet bulb is cooled by the evaporation of the water the dry bulb is not cooled
how do you work out humidity from a whirling hygrometer?
the temperature difference between the wet and dry bulb can be compared to a table of values to estimate humidity
how do you get an accurate result from a whirling hygrometer?
must be spun until there is no further cooling
what is the method for an electronic humidity meter?
make sure it is calibrated and read the number displayed on the screen
how is wind velocity usually measured?
using an electric anemometer
how can the use of an anemometer be standardised?
distance form ground
no obstacles to air flow
axis of rotation must be horizontal or vertical depending on design
impeller type anemometers must face into the wind
what is a Secchi dick used to measure?
water turbidity
what is the method for a secchi dick?
lower the disk into the water until the black and white sectors cannot be distinguished
record the depth of the disk(length of string below water)
