Name: ____________________
Period: ___
Date: _______________
Observing Homeostasis
Purpose:
To determine how fish maintain homeostasis in a water environment
Background:
_________________________________________________________
_________________________________________________________
Materials:
- Fish aquarium
- Water
- Ice/Hot water
- Goldfish (medium sized)
- Thermometer
- Small dip net for catching fish
- Watch/Clock with a second hand
Variables:
___________________________ depends on ______________________________________
Dependent Variable - DRY
Independent Variable – MIX
Control Variables:
Procedure:
1. Fill aquarium 3/4 way with water.
2. Using a small dip net, catch a goldfish without harming it in anyway, and place it in.
3. Allow the goldfish to settle into its new environment for several minutes.
4. Measure the beginning temperature of the water in the container and record.
5. Count the number of times the gills move in 1 minute at the beginning temperature.
6. Place ice in the beaker to lower the temperature of the water SLOWLY.
7. Every time the temperature of the water drops 2 o C, measure the number of times the gills
move in 1 minute. WARNING: It is extremely important to add ice slowly as to not drop
the temperature of the water too quickly and miss a measurement.
8. Continue this process until you reach 0 o C or a temperature at which the gills of the goldfish
stop moving, whatever comes first.
9. Fill out your table with the temperatures and number of gill movements in 1 minute.
10. Once you are finished with your measurements, take any remaining ice from the beaker and
allow the water to stand and return to room temperature. Do not remove the goldfish from the
water till you are told to.
Data and Observations
Beginning Temperature of Water: ______Co
Temp of Water Co Breathing rate of Fish
(Gill count in 1 minute)
Beginning Breathing Rate of Fish: _____
Qualitative Data
(What’s happening?)
Results: graph with labels
Conclusions: Analysis/Discussion
1) What is the definition of homeostasis?
2) What happens to the rate at which gills move when the temperature changes?
3) Why does a fish move its gills less in cold water than in warm water?
4) How do gills help fish maintain homeostasis?
5) EXTRA CREDIT: Name a qualitative (written details) and quantitative (numbers) data
measurements made during the lab.
Qualitative Quantitative -