## Teacher Guide: Lesson 13.4

The Weekly Reader Connections feature on **Kids' Place Houghton Mifflin Math** provides your students with additional information about the topics that appear in the Curriculum Connection feature in their student books.

The article “Postcards from Pluto?” informs students about NASA's proposed New Horizons mission which is to be launched in 2006 for the purpose of exploring Pluto, its moon, and the Kuiper Belt. Before students begin the reading, point out that Pluto differs in many ways from the other planets. It is so different that scientists are still not sure whether or not it be considered a planet.

For the Word Wise activity, students identify the two vocabulary words that are both nouns and verbs, probe and orbit, and write original sentences using the words as each part of speech.

Scientific notation is introduced in the Data Hunt activity. Students begin by learning that a light year is a distance. Explain that this distance is so great that just one light year is more than 63,000 times greater than the distance from Earth to the Sun.

Write the distance of one light year on the board this way: “9,500,000,000,000” Starting at the rightmost zero, have the students count the places with you aloud, moving to the left, until you reach the 5. Once having counted eleven zeroes plus one for the 5, students should understand that 9.5 x 10^{12} is another name for 9 trillion, 500 billion, or 9.5 trillion.

Have students write the distance 4,400,000,000 km in scientific notation: **4.4 x 10 ^{9}**. If time allows, you may wish to ask students to express the distance noted in the article, “2.9 billion miles across the solar system...” in scientific notation:

**2.9 x 10**.

^{9}