Intonation is the rise and fall in the pitch or tone of your voice as you read aloud. Use this passage to practice reading with proper intonation. Print a copy of this passage from InsideNG.com to help you monitor your progress.
Astronomers were the first to notice the growing problem of light pollution. They began to realize it in the 1970s. They were shocked when they looked into their telescopes and saw that some of the stars and planets that they had studied were gone. They were still there, of course, but city lights made them impossible to see.
Nights started to get brighter more than a century ago. The first long-lasting lightbulb was invented in 1879. Companies began to install electric power lines across the country. More and more people used electricity for lighting.
At the same time, the population grew. Many people moved to the United States. In 1900, there were 76 million Americans. There are more than 300 million today. More people now live in cities and suburbs, and their lights create light pollution.