Research methods: Abiotic factors

Question 1

what abiotic factors can be measured using electronic meters?

Answer 1

temperature
pH
dissolved oxygen
light level
wind or water velocity

Question 2

What must be done to make sure electronic meters are accurate?

Answer 2

must be calibrated by adjusting its reading to be the same as a meter that is known to be accurate

Question 3

what should be done if a meter cannot be calibrated?

Answer 3

percentage error should be noted so results can be adjusted

Question 4

what can be used to measure light intensity?

Answer 4

a calibrated light meter

Question 5

how can a light meter be standardised?

Answer 5

the same person holds it at the same height
or use a meter stick

Question 6

what 2 methods for measuring humidity are there?

Answer 6

whirling hygrometer
electronic humidity meter

Question 7

what is a whirling hygrometer?

Answer 7

traditional method for measuring humidity

Question 8

how does a whirling hygrometer work?

Answer 8

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

Question 9

how do you work out humidity from a whirling hygrometer?

Answer 9

the temperature difference between the wet and dry bulb can be compared to a table of values to estimate humidity

Question 10

how do you get an accurate result from a whirling hygrometer?

Answer 10

must be spun until there is no further cooling

Question 11

what is the method for an electronic humidity meter?

Answer 11

make sure it is calibrated and read the number displayed on the screen

Question 12

how is wind velocity usually measured?

Answer 12

using an electric anemometer

Question 13

how can the use of an anemometer be standardised?

Answer 13

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

Question 14

what is a Secchi dick used to measure?

Answer 14

water turbidity

Question 15

what is the method for a secchi dick?

Answer 15

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)

Question 16

what are the limitations of secchi disks?

Answer 16

depth judgement is subjective
sunlight levels may affect visibility
water may not be deep enough for the segments to become indistinguishable

Question 17

what is the method for a turbidity bottle?

Answer 17

add a standard depth of water to a turbidity bottle
hatched circles at the bottom of the bottle are observed to see which are obscured
note coarsest circle which cannot be distinguished

Question 18

what are the limitations of turbidity bottles?

Answer 18

judging which circles can be distinguished is subjective
light levels may affect visibility

Question 19

what is the most common way to measure the concentration of ions in solution?

Answer 19

colourimetry where the extent of a colour change involving the ions tp be measured is used to estimate ion concentration

Question 20

what is the method for using test strips?

Answer 20

have bands that change colours when they react with the ion to be measured
strips are dipped into the solutions being analysed and compared with a reference colour chart

Question 21

what is the method for a electronic ion reader?

Answer 21

add a reagent to test solution
intensity of colour produced measured by light meter that is adjusted to measure specific light wavelength

Question 22

what is ion selective electrodes?

Answer 22

electronic probe is put into test solution
electrode potential that is produced by the solution between two electrodes is used as a measure of ion concentration

Question 23

what are the limitations of concentrations of ions in solution? (pH research methods)

Answer 23

presence of other ions can lead to inaccurate results

Question 24

what is the method for a secchi dick?

Answer 24

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)