Some good projects for science/technology/engineering/math fairs, or STEM fairs, include building a model of human lungs to see how breathing affects them, making a solar oven, building a robot that can do a specific task such as search and rescue, and testing a mathematical hypothesis about student heights. STEM fair projects can focus on just science, technology, engineering or mathematics, or they can combine any of all of these disciplines.
Students can use balloons, a soda bottle and a Y-shaped tube to make a model of human lungs . The Y tube acts as the bronchii, connecting the lungs to the airway. Two balloons represent the lungs, and a balloon fastened to the cut-off bottom of the bottle acts as the diaphragm. When a student pulls on the bottom balloon, the change in pressure causes the "lungs" to inflate, as though a person is inhaling. Releasing the bottom balloon deflates the lung balloons, as with an exhalation.
A student can make a solar oven from a pizza box by cutting a flap in the box lid, lining it with foil, lining the box bottom with black paper, making the box airtight with plastic wrap, and insulating it with newspaper. To cook, the student puts food such as nachos with cheese inside and leaves the oven outside with the flap open on a warm, sunny day between 11 a.m. and 2 p.m., during which time the cheese melts.
Making a search-and-rescue robot involves using a radio-controlled toy car and a video camera. The student then drives it remotely based on what he sees via the camera.
A math project might start with a hypothesis that the mean, median and range of student heights in one grade differs from those in another grade. Students measure their fellow students' heights, record the data, perform the calculations and analyze their findings.