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The materials required for this science fair project:
- 1 empty aquarium with a top side cover
- 40 mosquitoes
- 1 can of mosquito repellant containing DEET
- 1 bottle of lemon grass oil
- 4 participants
- 1 stop watch


1. For this science fair project, the independent variable is the type of mosquito repellant used – lemon grass oil or a DEET-based mosquito repellant. The dependent variable is the number of mosquitoes that come to rest on the participant’s hand. This is determined by observing and counting the mosquitoes on the participant’s hand. The constants (control variables) are the number of mosquitoes in the aquarium tank and the size of the aquarium tank.

2.  Forty mosquitoes are  caught or bred from a mosquito egg raft for this science fair project.  The mosquitoes are then released into the aquarium and the cover is closed.

3.  DEET-based mosquito repellant and  lemon grass oil  is first applied on a small area of the participant’s skin to check for any sensitiveness or allergic reactions. Four participants without any reactions to the insect repellants are selected.

4. The participants are first made to place their hand inside the aquarium for 30 seconds and the number of mosquitoes sitting on their hand is counted and recorded in the table given below.

5. The participants left hand is then coated with the DEET based mosquito repellant. They are then requested to place their left hand in the aquarium once more and the number of mosquitoes that come to rest on the skin of their hands within the next 30 seconds is counted. The result is recorded in the table given below.

6. The participant’s right hand is now coated with  lemon grass oil. They are requested to place their right hand in the aquarium for 30 seconds. The number of mosquitoes that come to rest on their right hand is counted and recorded in the table given below.

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Complexity level:
Project cost ($):
Time required:
1 day to prepare, 1 hour for science fair project
Material availability:
Easily found
Safety concerns:

Keep mosquito repellant away from children. Your will need 4 adults who are willing to expose their hands to the mosquitos.