In this lesson, students will experiment with paper helicopters.  Students will manipulate the helicopters by changing wing length and helicopter mass, to discover the optimal wing length for their flying apparatus.  Students will measure the flying time for their helicopters. Student will then analyze their data by creating a class scatter plot graph.  Students will utilize a line of best fit to develop a Wing length to weight ratio to predict the optimum wing length for any given body weight.  Students will then apply this concept to various bird species. Students look at various groups of birds and relate wing length to the fitness of the species of bird.