Introduce the butterfly life cycle to your young scientists. Show your students pictures of the species of butterfly that you plan to grow within the classroom -- commonly, these are monarch (also known as milkweed) butterflies. Explain the changes and growth that students can expect to see in your butterfly-growing environment, which you should set up within the classroom but you may wish to keep at the back of the room so it does not generally distract your youngsters.
Set up a large tank with a mesh lid, so your caterpillars and butterflies will receive plenty of air. The hardest part of setting up your butterfly farm is finding a leaf with plenty of butterfly eggs on, although you can alternately collect a handful of already-hatched caterpillars. Set up your tank so it contains roughly a dozen eggs or caterpillars, and make sure there are plenty of plants and greenery within the tank to feed them. Keep your tank in a stable room temperature and environment, ensuring that it is not in direct sunlight.
Allow your students to study the life within the tank once each day. Students should look at the eggs, caterpillars, chrysalis and butterfly hatching using a magnifying glass. Get students to chronicle their observations in a number of ways, such as drawing pictures of each stage of the life cycle. You might also wish to set up a video camera to record the changes in the tank as the butterfly hatching from the chrysalis, for example, can occur in the space of 10 to 15 minutes and so might be missed by your class.
Students observing the butterfly life cycle for a presentation or science fair should look to take as many photographs of the cycle as possible. Young scientists can present their results in the form of graphs, such as working out the length of time the butterfly spent at each stage of the life cycle before working it out as a percentage and displaying it as a pie chart. Students using butterfly life cycle as a presentation or science fair should also describe each stage of the cycle and the changes that occur in order to present a rounded and tidy project.