Science Fair Projects on Fluoride's Affect on Daphnia

Daphnia and Fluoride

If you are interested in creating a biology or a medical science fair project then consider using the daphnia. Daphnia is a water flea. They make great test subjects as they are easy to manipulate and they reproduce rapidly.

PURPOSE

The reason for my experiment was to determine if the amount of fluoride affects the survival rate of Daphnia.

I became interested in this idea when the CNN news said, "There is too much fluoride in our water, which might cause medical problems." So, I decided to test it.

The information gained from this experiment will help people realize how much fluoride to use for human health reasons.

HYPOTHESIS

My hypothesis is that 0.01% of fluoride will kill the Daphnia.

I base my hypothesis on The World Book Encyclopedia 1998, which stated, "The level most commonly used in fluoridated water is 1ppm." One ppm is the same as 0.0001%.

EXPERIMENT DESIGN

The constants in this study were:

• the type of Daphnia
• amount of water
• temperature of the water
• amount of Daphnia tested on in a group
• place where the Daphnia were being tested
• amount of light

The manipulated variable was the amount of fluoride.

The responding variable was the number of Daphnia that died in a certain amount of time.

To measure the responding variable I used a microscope to determine if the Daphnia were alive, based on a visible heartbeat.

MATERIALS

PROCEDURES

1. Gather materials.
2. Have 5 groups of Daphnia with 20 in each group.
3. Put each Daphnia group in their own petri dish.
4. Put 40 mL of water in the petri dishes.
5. Put 1% amount of fluoride in the A group
6. Check the Daphnia under the microscope right away, then every15 minutes until 1 hour to see if the heart is still beating.
7. Put .1 % of fluoride in the B group.
8. Check the Daphnia under the microscope right away, then every 15 minutes until 1 hour to see if the heart is still beating.
9. Put .01 % of fluoride in the C group.
10. Check the Daphnia under the microscope right away, then every 15 minutes until 1 hour to see if the heart is still beating.
11. Put .001% of fluoride in the D group
12. Check the Daphnia under the microscope right away, then every 15 minutes until 1 hour to see if the heart is still beating.
13. Put no fluoride in the E group (Control group).
14. Repeat steps 3-13 one more time.
15. See how much fluoride is safe for Daphnia survival

RESULTS

The original purpose of this experiment was to determine if the amount of fluoride affects the survival rate of Daphnia.

The results of the experiment were that .01 % of fluoride is safe for Daphnia survival.

CONCLUSION

My hypothesis was that .01% of fluoride would kill the Daphnia.

The results indicate that this hypothesis should be rejected.

Because of the results of this experiment, I wonder if this amount of fluoride would affect shrimp, fish, or small mammals.

If I were to conduct this project again I would