Activated carbon and pesticides
The materials required for this science fair project:
- 40 flies
- Plastic bags
- 4 over-ripe bananas
- 1 digital weighing scale
- 1 measuring cylinder
- 1 bottle of distilled water
- 1 bottle of activated carbon
- 1 can of malathion pesticide spray
- 4 empty aquarium tanks with top cover
- 1 knife
- 3 spray containers
1. For this science fair project, the independent variable is the concentration of activated carbon solution – 0.1gram/100ml, 1.0gram/100ml or 10gram/100ml. The dependent variable is the number of flies still alive in each aquarium at the end of the 1-hour period. This is determined by observing the number for flies still alive every 10 minutes. The constants (control variables) are the over-ripe banana, the size of the fish tank used for the experiment, and the concentration of the Malathion spray.
2. Forty flies are caught in plastic bags (not a very pleasant experience, but you can try catching them at garbage dumps) or by attracting them with rotting food.
3. The 3 spray containers are labeled A, B and C. Using the digital weighing scale, 0.1mg of activated carbon is added to container A, 1.0mg in container B and 10mg in container C. 100ml of distilled water is added to all the 3 containers. The solution in each container is stirred/mixed before the container is resealed with its spray nozzle-top.
4. The 4 aquariums are labeled as A, B, C and D. Overripe bananas are cut in half and the exposed area is sprayed with malathion spray. One of the bananas is placed in the aquarium marked as D. The liquid in container A is sprayed over the exposed surface of one of the bananas which is then placed in the aquarium marked A. Similarly, sprays B and C are sprayed over the other bananas and then placed in aquariums B and C.
5. Ten flies are released into each of the 4 aquariums. The number of flies still alive is observed every 10 minutes and recorded in the table given below.
Ensure that safety masks, goggles and gloves are worn at all times when handling the Malathion and the flies. Malathion is extremely toxic and should be handled properly, in a controlled laboratory under the supervision of your science teacher.