skills worksheet active reading - shadyside schools...

Name Class Date _______________________________ ___________________ __________________

Skills Worksheet

Active Reading

Section: Renewable Energy Today Read the passage below and answer the questions that follow.

Solar cells, also called photovoltaic cells, convert the sun’s energy into electricity. Solar cells were invented more than 120 years ago, and now they are used to power everything from calculators to space stations. Solar cells have no moving parts, and they run on nonpolluting power from the sun. So why don’t solar cells meet all of our energy needs? A solar cell produces a very small electrical current. So meeting the needs of a small city would require covering hundreds of acres with solar panels. Solar cells also require extended periods of sunshine to produce energy. This energy is stored in batteries, which supply electricity when the sun is not shining.

Despite these limitations, energy production from solar cells has doubled every four years since 1985. Solar cells have become increasingly efficient and less expensive. Solar cells have great potential for use in developing countries, where energy consumption is minimal and electricity networks are limited. Currently, solar cells provide energy for more than 1 million households in the developing world.

IDENTIFYING MAIN IDEAS

One reading skill is the ability to identify the main idea of a passage. The main idea is the main focus or key idea. Frequently, a main idea is accompanied by supporting information that offers detailed facts about main ideas. In the space provided, write the letter of the term or phrase that best completes each statement or best answers each question.

1. Solar cells convert the sun’s energy into _____ a. light. b. heat. c. electricity. d. pollution.

2. What factor regarding solar cells has doubled every four years since _____1985? a. the number of solar cells produced b. the amount of energy produced by solar cells c. the number of people who use solar cells d. the price of solar cells

3. Solar cells have great potential for use in _____

Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor.

Holt Environmental Science ! Renewable Energy7

Name Class Date _______________________________ ___________________ __________________

a. cities. c. factories. b. private homes. d. developing countries.

RECOGNIZING SIMILARITIES AND DIFFERENCES

One reading skill is the ability to recognize similarities and differences between two phrases, ideas, or things. This is sometimes known as comparing and contrasting. Read the following questions and write the answers in the space provided.

4. How are solar cells different from most other power sources? _______________________________________________________________

_______________________________________________________________

5. How are solar cells of today superior to solar cells of the 1980s? _______________________________________________________________

_______________________________________________________________

VOCABULARY DEVELOPMENT

In the space provided, write the letter of the definition that best matches the term or phrase.

6. photovoltaic cells _____ 7. solar panels _____ 8. energy consumption _____ 9. batteries _____

RECOGNIZING CAUSE AND EFFECT

One reading skill is the ability to recognize cause and effect. Read the following questions and write the answers in the space provided.

10. How are solar cells used today? _______________________________________________________________

_______________________________________________________________

11. Why are solar cells particularly suitable for developing countries? _______________________________________________________________

_______________________________________________________________

12. Why aren’t solar cells used to meet all of our energy needs? _______________________________________________________________

_______________________________________________________________

Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor.

Holt Environmental Science ! Renewable Energy8

a. power usage b. store energy collected by solar cells c. convert the sun’s energy into electricity d. collections of solar cells

TEACHER RESOURCE PAGE

!85

270 Chapter 10 • Safe Drinking Water NEL

10.3 The Water Cycle Water is the only substance that exists on Earth in each of its three states. Water easily changes from one state to another. Water sometimes changes its location by changing state in a continuous pattern called the water cycle. Th e water cycle is self-renewing and constant. Th e Sun provides the energy to power the water cycle.

Changes of StateWhen water changes state in the water cycle, the total number of water particles remains the same. Th e changes of state include melting, sublimation, evaporation, freezing, condensation, and deposition. All changes of state involve the transfer of energy. Figure 1 shows how the water particles in each state behave as energy is added or removed.

When solid ice gains thermal energy, it changes state from solid ice to liquid water in a process called melting. Ice cubes in a cold drink, for example, gradually melt. Each spring you see snow melt into slush and puddles.

Sometimes adding thermal energy to solid ice causes a change of state from a solid to a gas. Th is change, directly from a solid to a gas without becoming a liquid, is called sublimation. On crisp, dry winter days you might notice that snow banks shrink, or ice gradually disappears, without fi rst becoming slushy and wet.

When water absorbs enough thermal energy, it becomes a gas (water vapour). Th is process is called evaporation. Water vapour mixes with the air and seems to disappear. For example, wet clothes on a washing line dry because the water evaporates into the air.

water cycle: a continuous pattern in nature in which water moves as it changes state above, on, and below the surface of Earth

melting: the change of state from a solid to a liquid; occurs when a solid gains thermal energy

sublimation: the change of state from a solid to a gas without fi rst becoming a liquid; occurs when a solid gains thermal energy

evaporation: the change of state from a liquid to a gas; occurs when a liquid gains thermal energy

solid

sublimation

deposition

melting

gas

evaporation

releases energy (heat)requires energy (heat)

freezing condensation

decreasing thermal energy of particles

increasing thermal energy of particles

Figure 1 Energy is gained or lost whenever water changes state.

Questioning the TextTo maintain your reading focus and get more meaning from a text, ask questions as you read.

Begin by scanning the page and reading the title and headings. What questions come to mind about the water cycle?

Read the fi rst few paragraphs. Stop and refl ect on what you have read. What questions do you have? What more do you want to learn about this topic?

Move to the next paragraph and, again, stop to ask questions. The conversation in your head will help you think more deeply about your reading.

L I N K I N G T O L I T E R A C Y

Sci8_UnitD_Chap10.indd 270Sci8_UnitD_Chap10.indd 270 10/24/08 11:59:22 AM10/24/08 11:59:22 AM

10.3 The Water Cycle 271NEL

When water vapour loses thermal energy and becomes liquid water, condensation has occurred. Rain and dew are examples of condensation. A cold can of pop placed outside on a hot summer day oft en collects water droplets. Th is is because water vapour in the air condenses when it is cooled by the cold can.

Sometimes, removing thermal energy from water vapour causes it to become a solid, rather than a liquid. Deposition occurs when water vapour changes state directly from a gas to a solid. Deposition is the reverse of sublimation. One example of deposition occurs high in the atmosphere where the temperature is very low. In these conditions, water vapour forms snow without becoming a liquid fi rst.

Liquid water can also lose thermal energy and undergo freezing: changing state from a liquid to a solid. We see many examples of this in everyday life. Puddles, ponds, lakes, and even parts of oceans freeze when the water becomes cold enough.

Changes of State in the Water CycleWater moves around Earth in the water cycle. Figure 2 shows where water is found, the state in which it exists, and how it changes from one state to another. Look at Figure 2 carefully to fi nd water in each of its three states.

condensation: the change of state from a gas to a liquid; occurs when a gas loses thermal energy

deposition: the change of state from a gas to a solid; occurs when a gas loses thermal energy

freezing: the change of state from a liquid to a solid; occurs when a liquid loses thermal energy

Sun

condensation

sublimationdeposition

precipitation

surfacerunoff

surfacewater

groundwater

freezing(water storage

in ice and snow)surface runoff

(snowmelt into streams)

cloud formation(water storage in the atmosphere)

icewater vapour

evaporation

Figure 2 The water cycle

Reading Visual Text: The Cycle MapA cycle map is used to illustrate a process that repeats itself. In nature, the water cycle and the life cycle can be illustrated using a cycle map. Can you think of other processes that are repeated in nature?

L I N K I N G T O L I T E R A C Y


272 Chapter 10 • Safe Drinking Water NEL

Melting, Evaporation, and Sublimation in NatureSolid water includes permanent ice and snow in glaciers and over the polar regions, and ice and snow that form in the winter. Liquid water falls to the ground in the form of rain. Liquid water also forms when winter ice and snow begin to melt. Much of this water is called runoff . Runoff water fl ows downhill under the infl uence of gravity, through streams, rivers, and lakes. Some of the water eventually reaches the oceans. All the water on the surface of Earth is called surface water.

Some liquid water seeps into the ground. Th is water, called groundwater, trickles down through openings in the soil and cracks in rocks until it hits bedrock and cannot fl ow down any farther. Th e water spreads out until it fi lls all the available spaces in the loose rock and soil above the bedrock. Th e loose rock and soil become saturated with water. Th is saturated area is called an aquifer. Th e top surface of the aquifer is the water table (Figure 3). Occasionally, natural underground caverns also fi ll up with water.

Surface water evaporates and snow and ice sublime from Earth’s surface to become water vapour. Water vapour in Earth’s atmosphere acts like a blanket that traps thermal energy close to Earth. Melting, evaporation, and sublimation are processes that occur as a result of the increasing thermal energy of water particles (Figure 4).

runoff: water from precipitation and snowmelt that fl ows over Earth’s surface

bedrock

surface water

soil

groundwater

water table

aquifer

Figure 3 Groundwater saturates loose rock and soil to the level of the water table, forming an aquifer.

Sun

sublimation

surface runoff(snowmelt into

streams)


icewater vapour

evaporation

Figure 4 Ice melts into water or sublimes to form water vapour. Liquid water evaporates when thermal energy is added.

groundwater: water that seeps through soil and cracks in rock; source of water for underground springs and wells

aquifer: a geological formation of loose rock or soil that is saturated with groundwater

water table: the depth at which loose rock and soil below Earth’s surface are saturated with water; the upper boundary of an aquifer


10.3 The Water Cycle 273NEL

Condensation, Freezing, and Deposition in NatureOnce water vapour is in the atmosphere, low temperatures cause the vapour to either condense into a liquid or undergo deposition to form ice crystals. Water droplets and ice crystals in the atmosphere form clouds. Air currents move the clouds around the planet. Th e water droplets in clouds collide to form larger droplets that fall as rain. Ice crystals fall to the ground as snowfl akes. Both rain and snow are forms of precipitation—water that falls to Earth’s surface. Fallen snow may gradually accumulate as polar ice sheets (areas of ice at the North and South Poles), icecaps (permanent ice that covers land), and glaciers (rivers of ice that slowly fl ow down mountainsides).

At low temperatures, Earth’s surface water freezes and forms solid ice. Ice is slightly less dense than liquid water. Th is explains why, in the winter, lakes and ponds develop a layer of ice that fl oats on the liquid water underneath. As a result, animals and plants can survive through the winter without being frozen solid. Condensation, deposition, and freezing are processes that occur as a result of a decrease in the thermal energy of water particles (Figure 5).

Changes with the SeasonsWinter snow melts as spring arrives. Th e snowmelt fl ows into streams and rivers, and eventually into the oceans. Some of the snowmelt sinks into the ground, becoming groundwater. As surface water evaporates to become water vapour, the water cycle is repeated.

precipitation: solid or liquid water that falls to Earth’s surface

polar ice sheet: a frozen fi eld of ice covering either the North Pole or the South Pole

icecap: a large area of ice that permanently covers land

glacier: a river of ice, formed from snow accumulated over hundreds of years, that moves slowly downhill under the force of gravity

condensation

depositionfreezing

(water storagein ice and snow)


icewater vapour

Sun

Figure 5 Water vapour condenses and liquid water freezes when thermal energy is removed.

1. Look at Figure 2. Where can you fi nd each of the three states of water?

2. Describe the water cycle. Draw your own labelled diagram.

3. Briefl y describe how solid and liquid water may be converted to water vapour.

4. Describe how water vapour changes into solid and liquid water above Earth’s surface.

5. Does all surface runoff move directly into rivers, lakes, and oceans? Explain.

CHECK YOUR LEARNING

How can you apply what you have learned about the water cycle to the Unit Task?Unit Task

Go to Nelson ScienceGo to Nelson Science

To watch an animation of the water cycle,


Layers of Atmosphere Reading Questions

1. What are the different layers of the atmosphere based on?

2. What is the layer that most of the weather occurs in?

3. How high above Earth’s surface does this layer extend?

4. In which atmospheric layer do we find the o-zone layer?

5. What does the o-zone layer do?

6. What is the stratosphere and the mesosphere called?

7. At what altitude do the gases nitrogen and oxygen become less well mixed?

8. How dense is the thermosphere compared to the air at sea level?

9. Where is the ionosphere?

10. How do radio transmissions use the ionosphere?

11. What happens to temperature as you go higher in the troposphere?

12. Why does temperature increase in the stratosphere? The Atmosphere Layers

13. Which layer is the coldest?

14. How hot can the thermosphere get?

15. Draw the layers of the atmosphere in the box! Label each layer and tell how high it goes! The top of the box is 600 km.

skills worksheet active reading - shadyside schools...

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