Students should visit the library or conduct research online to determine common uses for limelight in the 19th century, prior to Edison's invention of the incandescent lamp. Comprehensive research should include the risks posed by burning limestone and the reasons it was replaced in stage spotlights, lighthouse lamps and meeting halls. Include any relevant health hazard information and conditions attributed to lime exposure. Students should also study contemporary uses for lime, including decomposition of dead organisms and create a timeline for their science project illustrating the evolving uses of lime's properties.
Students will need calcium oxide, hydrogen and oxygen to create their own limelight. A 2.5-kilogram unit of calcium oxide, 23 liters of pressurized oxygen and 23 liters of hydrogen can be ordered online to replicate the light produced in 19th century lighthouses to alert sailors to shoreline locations in the dark. Alternately, a miniature version of an antique spotlight can be produced with a small spot of quicklime, forceps and a blowtorch.
Students must store the gases in separate gasometers that combine into a single chamber with a series of three wire gauze filters and one expulsion jet. Science teachers can order these from an educational supplier, or advanced scientists may design their own. Follow package instructions to crystallize lime. Direct the gas expulsion jet at the lime crystal to illuminate. Use a stopwatch to determine how long the original limelights would supply visual warning to passing ships and discuss the safety hazards created by this early light source. To create a spotlight, grasp the quicklime chunk tightly with a pair of forceps. Extinguish room lights and illuminate the blowtorch. Touch it to the rock to burn the calcium oxide and produce a bright light.
After completing the experiment, students should record observations about the procedure and the results. In the presentation, a chart or graph comparing the chemical properties, brightness, costs and health risks associated with lime and modern lighting techniques should be included. Students should clearly outline the likely results if lime was still used in light production for theatrical performances and propose any possible useful modern applications for the light-producing properties of calcium oxide, such as an emergency light source in regions where electricity is unavailable.