Research Methods: Specific Practical Investigations Flashcards
Why can measuring water turbidity be used to monitor?
Soil erosion
What ways can be used to measure water turbidity?
Secchi disks and turbidity bottle- semi- quantitative or qualitative
Electronic meters- quantitative data
What do most electronic turbidity meters measure?
The amount of light that is scattered by the suspended particles in a water sample usually 90* to the angle which it entered the water
What does increased turbidity cause in the experiment?
More light to scatter so the light reading rises
What is needed for the turbidity laboratory experiment?
A dark room with no other light source for representative results
Light source
Tube to provide beam of light
Glass container (flask)
Light meter
What do the light readings provide from the turbidity test?
Relative values of the concentration of the suspended particles in the water samples
What factors must be standardised in effect of turbidity on light penetration test?
Brightness of the light bulb
Colour of light emitted by the light bulb
Distance to the sample holder
Material used to produce the calibration samples
How can noise level be measured?
An electronic sound level meter or a mobile phone
If uncalibrated meters are used then the same one should be sued to collect all the results
Why must you use the same uncalibrated equipment at each location?
Will ensure the degree of error in the results is constant so they can be compared with each other
what can a high or low pH conditions do to plants?
can denature proteins
inactivate enzymes
what must be considered when chosing a plant species for the effect of pH on germination?
small seeds
genetic uniformity
high normal germination rate
rapid germination
might not need to produce results directly applied to natural ecosystem
what is the number seeds and replicates needed for the effect of pH on seed germination?
each test must use enough seeds to produce results that can be distinguished from each other if there is a real difference
not so much that unnecessary work is needed
must be replicated so anomalies can be identified and results statistically valid
What should the pH range be for effect on pH on germination be?
pH range should fully cover range at whihc germinaiton can occur
established with prelimary study
should be below lowest pH at which germination occurred and above highest pH germination occurred
how long should the effect of pH on germination study be?
should be continued until it is clear that seeds that haven’t germinated aren’t going to
possibility pH may delay germinaiton must be accounted for
what must be standardised in the effect of pH on germination study?
temperature- ideally constant (form natural germination)
nutrient supply- not needed for germination only needed if gronw beyond initial stage
soil as growth medium repliactes natural condiotns but may effect pH
