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The materials required for this science fair project:
- A pair of identical male twins (8 to 10 years old)
- A pair of identical female twins (8 to 10 years old)
- A pair of  fraternal male-female twins (8 to 10 years old)
- 2 siblings (8 to 10 years old)
- An ink pad
- A piece of paper
- A roll of tissue paper
- 1 measuring tape
- 1 weighing scale


1. For this science fair project, the independent variable is the type of twins – identical male twins, identical female twins, male-female fraternal twins and ordinary siblings. The dependent variable is similarity found among the pairs. This is determined by making observations of the twins. The constants (control variables) are the age group, race, country/city of the participants. It is necessary to ensure that all participants are from the same locality and of the same race, to increase the reliability of our results.

2. The twins are examined as pairs, and the following comparisons made.

a. Hair – the similarity of the twins and sibling’s hair.. They are asked if they have used any color dye, straightening or curling  of their hair.

b. Facial features – the similarity in the faces of the twins and siblings is observed. The twins are asked if they have had any facial cosmetic surgery.

c. Height – the height of both the twins and siblings is measured against the wall using the measuring tape and compared.

d. Weight – the weight of the twins and siblings is measured using the weighing scale and compared.

e. Eye color – the colors of the twins and sibling’s eyes are compared.

f. Fingerprint –  fingerprints of the twins and siblings  are taken using the ink pad and placed on  a piece of paper. A comparison of the fingerprints is made.

3. The results from procedure 2 are recorded in the table given below.

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Complexity level:
Project cost ($):
Time required:
1 hour to prepare, 1 day for the science project experiment
Material availability:
The participation of pairs of twins of the same race is required
Safety concerns: