As girls enter their teenage years, they typically have an increased interest in gender differences and social interactions. While any middle-school science project would likely suit an eighth-grade girl, projects that examine the differences between males and females -- in psychological, social or physical realms -- may hold extra interest for female students.

Reaction Time, Age and Gender

Design an experiment to test the reaction time of boys and girls at various ages. Obtain an equal number of volunteers for each gender at each age. Use at least five boys and five girls at age 10; five boys and five girls at age 15; and five boys and five girls at age 20. Instruct each volunteer to sit in a chair and hold their hands out, spreading their thumbs and first fingers apart by 5 cm. Hold a meter stick above each volunteer and drop it without warning. Measure how much length passes before each volunteer catches the stick. Repeat several times with each volunteer, then average the results for boys and girls at each age.

Memory and Gender

Test the memory capabilities of girls and boys in the eighth grade. Begin by collecting five to 10 male and five to 10 female volunteers. For the first test, show each volunteer several black-and-white pictures of androgynous faces, identifying each as either male or female. After a few minutes, show the pictures again, asking the volunteer to identify which pictures show males or females. For the second test, show each volunteer a simple image for 30 seconds. Remove the picture, allow another minute to pass and ask the volunteer to duplicate the image from memory. For each test, average the accuracy of your volunteers by gender.

Emotional Identification and Gender

Test the accuracy of girls and boys in interpreting facial expressions. Obtain 10 to 20 volunteers of each gender, between the ages of 12 and 14. Obtain 10 pictures of individuals portraying different facial expressions such as happiness, anger, sadness, fear, disgust and surprise. Have each volunteer mark the emotion they believe each expression portrays. Compare the volunteers' answers with the actual emotion demonstrated. Average the percentage of accuracy for boys and girls to determine which gender demonstrates a better general understanding of emotional identification.

Contagious Yawns and Gender

Yawns have a contagious effect on many individuals. Some contagious behaviors, including yawning, occur in part due to perceived social cues about appropriate responses to the actions of others. Determine if gender has any bearing on this "contagious" effect and determine which gender picks up on social cues more frequently. Visit several eighth-grade classrooms and stand in front. The visitor should stand in front of the room and give several "stimulus" yawns, counting the number of male and female yawns that follow within a time period of five minutes. Repeat this procedure several times. Alternatively, if you cannot obtain permission to visit classrooms, gather three separate groups of volunteers, including five boys and five girls in each group. Test each group separately and average the number of response yawns given by boys and girls separately.