Darkling beetle larvae, also known as mealworms, do not suffer from being handled. This makes them ideal for younger elementary school children. For the price of oatmeal and some mealworms from your local pet store or an online supplier, your class can observe the life cycle of a darkling beetle. This beetle undergoes a complete metamorphosis, from egg to beetle, in as little as six to eight weeks.Your students can chart growth on a timeline, experiment with different kinds of grain for food and observe each stage for signs of change over time. If you want to show the egg stage, you can simply start the project early at home and allow the beetles to breed before starting your students' experiment.
Children are naturally fascinated by the chrysalis, or "cocoon" stage, of butterflies in particular. Students in urban settings may never have the opportunity to observe this monumental event without a classroom experiment. There are several kits available online and through educational retailers that will enable your class to enjoy raising butterflies. Your students will be able to observe the eggs, care for the caterpillars, watch the chrysalis form and open and enjoy the eventual emergence of the butterfly. Butterflies are somewhat more fragile than darkling beetles and best cared for by intermediate elementary school students.
There are also kits available online and through education centers that allow your class to watch the life cycle of a frog. While slightly more complicated than insect care, students will simultaneously learn about the needs and habits of amphibians while observing the life cycle. This experiment will require a longer time commitment. Amphibians enjoy a longer life span than insects and should never be released into the wild because of the possibility of infection of native species. Find an eventual home for any grown frogs before starting a frog experiment with your class.
Plants are perhaps the easiest life cycle experiment. Children love to plant seeds and watch them grow. Choosing a plant or variety of plants that will eventually be edible will increase interest in the project. If you live in a northern climate, lettuce and peas are some early crops that are relatively quick-growing for children to watch and can be started as early as March. Southern climates can enjoy year-round gardening projects. If possible, try to start a community garden plot for years of rewarding plant life cycle experiences.