Water Quality - Unit 2
The purpose of this experiment is for students to gain experience in
altering the temperature water and to observe how goldfish respond to
different temperatures in their environment.
- 3- goldfish
- 3 - 1000mL beakers
- 2-Large plastic tubs (37 cm x 31 cm)
Note: Read all of the instructions before
1. Make predictions on what will happen to the fish in the
Hot and Cold
- What is the expected behavior of the fish in the colder water?
- What is the expected behavior of the fish in the warmer water?
2. Place the Hot beaker in the
tub of hot water and the Cold in
the tub of ice water. The water in each tub should be at a level high
enough that most of each beaker is submerged. The third beaker is to
be left at room temperature (this is the Control
3. Place a thermometer in each beaker. Stir each beaker, making sure
all of the water in the beaker has a uniform temperature. You can use
the thermometer to stir the water, but remember to check the temperature
of the water periodically. When the temperature approaches the indicated
range for each beaker, you will have to watch the temperature more closely
to know when to take the beakers out of the tubs.
4. The desired
temperatures for each beaker are:
- the Control beaker’s temperature
should be between 20-25 º C
- the Cold beaker’s temperature
should be between 10-12 degrees º C
- the Hot beaker’s temperature
should be between 37-40 degrees º C.
5. When the water in the beakers reach these temperatures, remove them
from the tubs of ice water and hot water. Record the exact temperatures
of the water in each beaker.
Note: This may take 20-30 minutes because water
takes a long time to reach the desired temperature. Make sure that
the water in the beakers have stabilized at this temperature; begin
observations as soon as you remove the beakers from the hot and cold
6. Place one fish each in the Control
beaker, the Cold beaker and the
Hot beaker once the temperature
of the water in the beakers has stabilized and as soon as possible
following removal of the beakers from the water baths!!
7. After 20 minutes have
elapsed, make observations on the behavior of the fish. Is there a marked
difference in the speed that they move? Is their behavior different?
Is there a difference in their physical appearance?
8. Pick one of
the following physical movements to monitor in every goldfish:
- swishing of tail
- flexing of mouth
- flexing of gills
Each of these movements are done by the goldfish at a measurable rate
in a normal environment.
9. One student should count the goldfish’s movements in the Control,
Hot and Cold
beakers and one group member should serve as the timer. Count
the number of times the goldfish makes this movement over the period
of 1 minute. Record the rates
and compare them.
10. Compare your results with what you predicted. The results will
be based on any physical changes observed. Are the results the same
as your predictions or are they different? Is the behavior of the fish
in the hot and cold water different from the control group?