Group
Names: ____________________________________________________
Date: _______________________
Test kit
instructions need to be followed precisely. (A practice test with water
of known DO
content and pH
may be used before you begin the actual testing.)
You will
create a microcosm by adding sediment or fish to water in a bottle.
If your teacher has provided chemical reagent test kits you will test
the DO and pH
after 20 to 30 minutes. If you are using meters to measure DO and pH
you will sample every five minutes.
Type of
microcosm you are analyzing: ______________________________________
Experimental
Design
Add 150
ml of water to your microcosm bottle. Enter your prediction for the
initial DO and pH measurements into the table below. Reflect on what
you know about DO, pH, and water before making your prediction. Test
the DO and pH of your water sample before adding the sediments or fish.
(If using test kits, slowly pour water from your microcosm into the
test kit bottles, or take a sample with a pipette. Try not to splash
the water as you are transferring it to the kit bottles.) Record your
measurements in the table below. Then add your sediment or fish to
the
bottle.
Data
Collection
Describe
the contents of your microcosm
Sediment:
describe
_______________________________
– Or –
Minnows:
describe and indicate how many
_______________________________
Predict
what will be observed in your next measurements.
*Note: A
maximum of 30 minutes should be allowed for oxygen and pH changes to
develop. This prevents unnecessary minnow mortality.
Test
#
|
Time
|
Predicted
DO
|
Predicted
pH
|
Measured
DO
|
Measured
pH
|
1
|
|
|
|
|
|
2
|
|
|
|
|
|
3 |
|
|
|
|
|
4
|
|
|
|
|
|
5
|
|
|
|
|
|
Data
Management and Analysis
- How did your microcosms change?
Interpretation
of Results
- Describe the change and provide a reason for its occurrence.
Reporting
Results
Turn in your completed worksheet. |