Reading Metrics
Grade Level
Middle Grades (MG 4-8)
Book Level
6.1
Points
1.0
Fiction/Nonfiction
Nonfiction
Word Count
4071
Points per Word
0.000246
Page Count
32
Points per Page
0.03125
Description
In ancient times, warriors threw spears or fired arrows from bows. Today, soldiers shoot bullets from machine guns that fire up to 3,000 times a minute. Follow the steps in the process that led from spears and cannonballs to rockets and missiles.