Classroom Handouts ready to print. Students' work should clearly show an understanding of the progression from interstellar cloud to protostar, to red giant to either planetary nebula and white dwarf OR to supernova as described in the teacher background information . It is strongly suggested that students assess one another's work. The sun, the earth, and the rest of the solar system formed from a nebular cloud of dust and gas 4.6 billion years ago. The early earth was very different from the planet we live on today.
Stars produce energy from nuclear reactions, primarily the fusion of hydrogen to form helium.
These and other processes in stars have led to the formation of all the other elements.