Chapter 4: Factors, Fractions, and Exponents

#3005 Eyes on the Universe: Looking Into Time - Astronomers think of telescopes as “bigger eyes” that allow them to look, not only deep into space, but back into time.

#3006 Eyes on the Universe: Planetary Systems— New telescopes will soon allow astronomers to study the planetary systems of other stars and compare them to our own Solar System. Movie length: 3:03

Ask students to guess how many meters to the moon, Mars, the nearest star. Then use the chart in problem 2 to give them the correct figures. Explain the meaning of the exponent after the 10, and have students practice a little bit converting small powers of ten to standard notation. Then give them the distance to the center of our galaxy, from the chart, and ask them to write that out in standard notation.

Explain that scientists, engineers, and other people who use mathematics in their jobs use exponents to make it easier to write very large numbers, and that they are going to learn more about how to do that in this chapter.