Good eighth-grade science project ideas include making an electric motor, using the golden ratio to understand beauty and determining how stress affects the body. All of these projects are engaging and encourage young scientists to conduct more of their own research.
Making a simple electric motor helps students understand how energy can be converted into mechanical energy through the interactions of electromagnets, current and a magnetic field. If the students are successful, the completed motor continues spinning only when it is pushed in the correct direction.
Investigating ideas of beauty using the golden ratio is an interesting way for students to understand how certain notions of beauty are determined by the symmetrical feature shapes that adhere to the ratio of the irrational numbers 0.618 and 1.618. The experiment allows experimenters to poll other students about how attractive celebrities are and to calculate how well the celebrity's appearance adheres to the golden ratio.
A practical experiment is to measure if the human body experiences changes in temperature when a person experiences stress. It involves giving 10 test subjects a difficult test and recording their basal body temperature before the test and after the test as well as asking them to rate their stress level before the test. The experimenter can then examine if the highest increases in temperature happened to those who felt the most stressed.