Astronomy Lesson Plan: Black Holes

Since there has been a lot that has been said about Black Holes, and since most high school students know something about our solar system, I thought this would be an interesting lesson plan. Many students have visited the new Los Angeles Griffith Park Observatory which has opened recently. One day, in a science class, I passed out a sheet explaining the theory of Black Holes. After we read the information together, and had a discussion on it, I gave them a follow up lesson that they could complete and hand in when finished.

The information we read together:

Some of the most fascinating and mysterious objects in the heavens are black holes. In a way, they are quite frightening because they are not really there. They cannot be seen, but scientists believe that they are there. To understand these strange celestial phenomena, one must first know about the death of a star.

In some respects, black holes are not really extraordinary. They are quite simply the product of a dyeing star. According to scientists, after millions of years, stars burn up their hydrogen fuel and begin to cool and shrink. Then there is a tremendous explosion. As the outer layer is blasted into space, the star shines more brightly than million suns.

After the explosion, gravity begins to pull the remaining part of the star inward. The material becomes so compact and dense that a teaspoon of matter from it weighs millions of tons. The tremendous amount of weight of the outside of star causes it to collapse inward. If there is enough weight, the collapse continues until its density is so great and its gravity so strong that nothing, not even light, can escape from the surface. Since there is no light coming from the star, it cannot be seen. That's why scientists can only predict the existence of black holes. Not all collapsing stars, however, become black holes. If the outside weight is not strong enough, it stops collapsing and what is left is called a white dwarf.