Then they attach themselves to a leaf or stem by spinning a silk button. The skin quickly hardens into a shell called a chrysalis. Inside the chrysalis, caterpillars slowly change into butterflies. When butterflies emerge from the chrysalis, they extend their wings by pumping blood into them. It usually takes a couple of hours for the wings to dry and harden, then the butterflies can fly.
Science is constructed of facts as a house is of stones.
But a collection of facts is no more a science than a heap of stones is a house. Raise butterflies from caterpillars. The butterflies then can be released into the natural world. Monitor the yearly migration of monarch butterflies. Research and report on the differences between butterflies and moths.