How would you devise and execute a problem solving strategy that will yield a reasonable explanation for how a star is able to resist collapsing under its own gravitational attraction?

Answer 1

A star has a massive gravitational field that wants to pull all of its matter into a small volume. When the star formed, it tried to do just that, but when all of the gases were being compressed in the gravitational collapse, they were heated. As more and more compression increased the density of the material, the gases got hotter and hotter. The gas eventually reached temperatures where the nuclear fusion of hydrogen into helium began. The star lights up, and its collapse would be limited or stopped. All of the fusion reactions that are taking place around and through the core of the star are releasing energy. This energy creates the heat necessary to sustain the fusion reactions that are continuing. In addition, a lot of energy is being passed outward through the successive layers of the star, eventually to escape into space. The continuous generation of these massive quantities of energy by the fusion reactions results in lots of "extra" energy appearing in the core of the star. It won't stay there and wants to get out. These two ideas, the gravitational collapse and the continuous generation of massive amounts of energy in the core set the stage for a standoff. Gravity always pulls the mass of a star in, and energy generated from fusion is always trying to force everything apart. A star operates in equilibrium throughout its life with these two forces constantly struggling against each other. What happens in the end depends on the mass of the star, as it may just collapse and burn out, or it may go supernova. Your strategy to demonstrate why a star doesn't collapse on itself would include examples or models of gravity and demonstrate that it wants to "pull stuff in" all the time. You would also want to model or explain nuclear fusion, perhaps with a fusion thermonuclear weapon as a model, that demonstrates what happens when fusion reactions occur. Even just a few fusion reactions release tremendous quantities of energy, and this energy wants to force everything around the places where fusion occurred out and away (the nuclear blast). Modeling and demonstrating both gravity's pull and the "outward push" created by the energy released by nuclear fusion will be the keys to explaining why stars do not collapse under their own gravity.