Do you know where rain comes from? Read the following selection to learn more about precipitation. Then answer the questions that follow.

Transcription

1 North arolina Testing Program o you know where rain comes from? Read the following selection to learn more about precipitation. Then answer the questions that follow. Precipitation In rica, hile, the average rainfall is less than 1 millimeter per year. Many years pass with no precipitation at all. On the other hand, the average rainfall on Mount Waialeale on the island of Kauai in Hawaii is over 12 meters per year. That s more than enough to cover a three-story house! s you can see, rainfall varies greatly around the world. Water evaporates into the air from every water surface on Earth and from living things. This water eventually returns to the surface as precipitation. Precipitation (pree sip uh TY shun) is any form of water that falls from clouds and reaches Earth s surface. 3 Precipitation always comes from clouds. ut not all clouds produce precipitation. For precipitation to occur, cloud s or ice crystals must grow heavy enough to fall through the air. One way that cloud s grow is by colliding and combining with other cloud s. s the s grow larger, they fall faster and collect more and more small s. Finally, the s become heavy enough to fall out of the cloud as raindrops. roplets come in many sizes. elieve it or not, a raindrop has about a million times as much water in it as a cloud. Types of Precipitation In warm parts of the world, precipitation is almost always rain or drizzle. In colder regions, precipitation may fall as snow or ice. ommon types of precipitation include rain, sleet, freezing rain, hail, and snow. Rain The most common kind of precipitation is rain. rops of water are called rain if they are at least 0.5 millimeter in diameter. Precipitation made up of smaller drops of water is called mist or drizzle. Mist and drizzle usually fall from stratus clouds. Sleet Sometimes raindrops fall through a layer of air below 0, the freezing point of water. s they fall, the raindrops freeze into solid particles of ice. Ice particles smaller than 5 millimeters in diameter are called sleet. Freezing Rain t other times raindrops falling through cold air near the ground do not freeze in the air. Instead, the raindrops freeze when they touch a cold surface. This is called freezing rain. In an ice storm, a smooth, thick layer of ice builds up on every surface. The weight of the ice may break tree branches onto power lines, causing power failures. Freezing rain and sleet can make sidewalks and roads slippery and dangerous. loud Mist rizzle Raindrop Page 1

2 North arolina Testing Program Hail Round pellets of ice larger than 5 millimeters in diameter are called hailstones. Hail forms only inside cumulonimbus clouds during thunderstorms. hailstone starts as an ice pellet inside a cold region of a cloud. Strong updrafts in the cloud carry the hailstone up and down through the cold region many times. Each time the hailstone goes through the cold region, a new layer of ice forms around the hailstone. Eventually the hailstone becomes heavy enough to fall to the ground. If you cut a hailstone in half, you can often see shells of ice, like the layers of an onion. ecause hailstones can grow quite large before finally falling to the ground, hail can cause tremendous damage to crops, buildings, and vehicles. Snow Often water vapor in a cloud is converted directly into ice crystals called snowflakes. Snowflakes have an endless number of different shapes and patterns, all with six sides or branches. Snowflakes often join together into larger clumps of snow in which the six-sided crystals are hard to see. Precipitation from Prentice Hall Science Explorers Weather and limate 2000 by Pearson Education, Inc., publishing as Pearson Prentice Hall. Used by permission. 1. Which word best describes the habitat around rica, hile? 2. What has to happen in order for precipitation to occur? desert forest grassland The cloud s have to be heavy enough to fall. The cloud has to be a cumulonimbus or stratus. wetland The cloud has to have several strong updrafts. The temperature of the cloud has to be at least 0. Page 2

3 North arolina Testing Program 3. Which of the following determines whether precipitation will come as rain or as sleet? the amount of wind 6. What is the purpose of comparing a hailstone to an onion? to show how hailstones are layered the size of the clouds to illustrate the size of hailstones the type of clouds to show the weight of hailstones the air temperature to describe the damage caused by hail 4. What is it called when precipitation becomes icy only after touching the sidewalk? 7. Which of the following describes a snowflake? snow a frozen drizzle sleet several layers of ice hail a six-sided ice crystal freezing rain a round pellet of ice 5. What makes some hailstones larger than other hailstones? 8. ased on the information given, which of the following is the smallest? Larger hailstones occur when the air temperature is much colder. Larger hailstones occur when the ground temperature is much colder. Larger hailstones have moved more times through the cold region of a cloud. a mist a drizzle a cloud a rain Larger hailstones form in cumulonimbus clouds, but smaller hailstones do not. Page 3

4 North arolina Testing Program 9. What do sleet and snow have in common? oth are made up of ice. oth are produced by huge clouds. oth are six-sided crystals. oth develop from raindrops. End of Set In compliance with federal law, including the provisions of Title IX of the Education mendments of 1972, the epartment of Public Instruction does not discriminate on the basis of race, sex, religion, color, national or ethnic origin, age, disability, or military service in its policies, programs, activities, admissions or employment. Page 4

5 nswers to Grade 5 Reading omprehension Sample Items Question orrect Objective Passage Title Number nswer ategory Thinking Skill Number Precipitation 1 onnections nalyzing 2.02 Precipitation 2 ognition Knowledge 2.02 Precipitation 3 Interpretation nalyzing 2.05 Precipitation 4 ognition Knowledge 2.02 Precipitation 5 ognition Knowledge 2.02 Precipitation 6 ritical Stance Evaluating 3.01 Precipitation 7 ognition Knowledge 2.02 Precipitation 8 ognition Knowledge 2.02 Precipitation 9 ritical Stance Organizing 2.02 Friday, January 23, 2004 Page 1 of 1