1. Formation of Stars

Stars haven't always existed - they evolve from clouds of dust and gas (Nebula) that collapse under gravity to form Protostars. As the temperature and pressure increases the conditions for fusion then allow the star to 'burn' hydrogen as the star enters the stable Main Sequence phase. 

 

2. Evolution of Low Mass Stars

What will eventually happen to our Sun and other similar stars?

 

3. Evolution of Massive Stars

Big stars, many times the mass of our Sun, end up as Super Red Giants towards the end of their lives.

 

4. The Hertzsprung-Russell Diagram

Named after Ejnar Hertzsprung and Henry Norris Russell this graph of the stars we see in the Universe is the reason why we call stable stars 'Main Sequence' stars. It can also be used to visualise the life cycle of a star as it moves from the Main Sequence to a Red Giant then a White Dwarf, or perhaps even a Red Supergiant.