Dạy Tiếng Anh cho trẻ không phải là luôn luôn bắt con phải ngồi trên bàn học và chiến đấu với những cuốn sách dày cộm. Có rất nhiều cách học để nâng cao vốn hiểu biết tiếng Anh cho bé như qua sách truyện, phim ảnh hay chơi các trò chơi về Tiếng Anh. Đặc biệt với kho tàng tài liệu Tiếng Anh khổng lồ trên mạng Internet, các bố các mẹ hãy tận dụng để trẻ có những khoảng thời gian học Tiếng Anh vừa vui vẻ lại vừa bổ ích. Thủ thuật máy tính đã sưu tầm được rất nhiều nguồn tài liệu Tiếng Anh trẻ em vô cùng thú vị, các bố các mẹ hãy tham khảo nhé
Earth's Resources Lessons 1– Grade CA Unit w w w.harcour tschool.com ISBN-13: 978-0-15-349212-9 ISBN-10: 0-15-349212-0 Ë|xHSKBPDy492129zv*:+:!:+:! CXECA08ARD606_LLR_CVa.indd 2-3 > 2/20/06 4:48:09 PM Think About the Reading What can you to help you remember what you have learned about our resources? What questions you have after reading this book? How can you find the answers to your questions? Copyright © by Harcourt, Inc All rights reserved No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publisher Requests for permission to make copies of any part of the work should be addressed to School Permissions and Copyrights, Harcourt, Inc., 6277 Sea Harbor Drive, Orlando, Florida 32887-6777 Fax: 407-345-2418 HARCOURT and the Harcourt Logo are trademarks of Harcourt, Inc., registered in the United States of America and/or other jurisdictions Hands-On Activity Think about what you have learned about classifying material resources Create these charts and explain how they compare and contrast Make a chart of renewable resources that you use in your daily life Make a chart of the non-renewable items that you use in your daily life Printed in the United States of America ISBN-13: 978-0-15-349212-9 ISBN-10: 0-15-349212-0 10 179 15 14 13 12 11 10 09 08 07 06 If you have received these materials as examination copies free of charge, Harcourt School Publishers retains title to the materials and they may not be resold Resale of examination copies is strictly prohibited and is illegal Possession of this publication in print format does not entitle users to convert this publication, or any portion of it, into electronic format CXECA08ARD606_LLR_CVa.indd 4-5 School-Home Connection Discuss with a family member different energy resources that you have learned about Research with your family whether you live near a type of energy plant that you have studied What kind of plant is it? 2/20/06 4:48:51 PM Earth’ s Resources Lessons 1–2 Lesson How Are Natural Resources Classified? .2 Lesson How Do Energy Resources Differ? 10 Visit The Learning Site! www.harcourtschool.com CXECA08ARD6061-2.indd 2/23/06 1:44:57 PM VOCABULARY renewable resource nonrenewable resource fossil fuel How Are Natural Resources Classified? The wind farm uses a renewable resource The wind will blow again Once the coal is used up it is gone and cannot be renewed Coal is a nonrenewable resource CXECA08ARD6061-2.indd 2/20/06 3:58:56 PM Coal is a fossil fuel we burn for energy CXECA08ARD6061-2.indd 2/20/06 3:58:57 PM READING FOCUS SKILL COMPARE AND CONTRAST You compare things by looking for ways things are similar You contrast things by looking for the ways things are different Compare and contrast how renewable and nonrenewable resources differ Renewable Resources A natural resource is a material found in nature that is used to meet a need We use natural resources every day Water is a natural resource that we use for drinking, and cooking foods A renewable resource is always available It can be replaced quickly through a natural process A renewable resource includes sunlight, air, fresh water, and many kinds of plants and animals Water is a renewable resource It is renewed through the water cycle CXECA08ARD6061-2.indd 2/20/06 3:58:57 PM Young redwoods in a greenhouse in Fort Bragg, California Some renewable resources are recycled through natural processes Plants and animals are renewable because they can reproduce Adult trees reproduce and the young trees grow Natural resources like these must be managed carefully Give one example of a natural renewable resource CXECA08ARD6061-2.indd 2/20/06 3:59:08 PM Firewood is biomass, a renewable energy Renewable Energy and Resources Natural resources that people use to produce electricity are called energy resources Some energy resources can be replaced quickly A campfire is a form of fuel called biomass Biomass is matter from living things Because biomass can grow back it is a renewable energy resource Some energy resources are part of Earth’s crust The heat from this area can be used to warm homes and generate electricity The heat from Earth’s surface is a renewable energy resource CXECA08ARD6061-2.indd 2/20/06 3:59:13 PM Solar energy collects energy from the sun Solar energy is a type of renewable energy Solar cells can change solar energy into electricity The sun heats Earth’s atmosphere This can cause wind, which is also a renewable energy resource How is solar energy different from other renewable energy resources? Wind farms use wind to produce electricity Wind is a renewable energy resource CXECA08ARD6061-2.indd 2/20/06 3:59:28 PM Nonrenewable Resources Not all of Earth’s resources are renewable We call these resources nonrenewable A nonrenewable resource is a resource that cannot be replaced The rain forest is an ecosystem If it is destroyed it could take hundreds of years to grow back The rainforest is a nonrenewable resource If the forest is cut down or destroyed, the trees and habitats are gone Without a home the rainforest communities may die out and never come back Rocks, minerals, soil and plants are all examples of resources that cannot easily be replaced Rocks for example may take millions of years to travel through the rock cycle and form How is a nonrenewable resource different from a renewable resource? A rainforest is a nonrenewable resource It must be protected CXECA08ARD6061-2.indd 2/20/06 3:59:38 PM Nonrenewable Energy Resources A fossil fuel is an energy resource that cannot be replaced Fossil fuels formed from the remains of living things This type of fuel takes millions of years to form So, when supplies are used up, there will be no more left Fossil fuel is a nonrenewable energy resource Coal, oil and natural gas are fossil fuels Uranium is a metal that is used in nuclear plants to produce electricity Uranium is a nonrenewable energy resource Once all of this metal is mined from Earth’s surface, no more can be made How are fossil fuels and uranium similar? Coal comes from the remains of plants that died millions of years ago Review Complete these compare and contrast statements A is always available and can be replaced quickly A is a resource that cannot be replaced easily/ There is a limited amount A is an energy resource that is formed over millions of years It comes from the buried remains of living orgamisms Sun and water are that are always available and can be quickly replaced CXECA08ARD6061-2.indd 2/20/06 3:59:49 PM VOCABULARY nuclear energy radioactive decay hydroelectric energy geothermal energy How Do Energy Resources Differ? Nuclear energy can be converted to electrical energy in a nuclear reactor Some elements have radioactive decay as thier atoms give off particles 10 CXECA08ARD6061-2.indd 10 2/20/06 3:59:56 PM Water is converted to electricity through a hydroelectric energy station This geothermal energy plant uses heat from Earth to make electricity 11 CXECA08ARD6061-2.indd 11 2/20/06 4:00:05 PM READING FOCUS SKILL COMPARE AND CONTRAST You compare things by looking for ways things are similar You contrast things by looking for the ways things are different Compare and contrast how energy resources are converted into useful forms of energy Fossil Fuels Useful energy resources are those that are not expensive and which not cause great harm to the environment Currently, the cheapest energy resources to use are fossil fuels Coal, oil, and natural gas are all fossil fuels There are environmental costs to using fossil fuels Each of these fuels are taken from Earth’s crust The removal costs money Air pollution is a cost to people’s well-being and damages our environment Every energy resource has advantages and disadvantages What is an advantage to using fossil fuels? Air pollution from burning fossil fuels is a disadvantage to using this energy resource 12 CXECA08ARD6061-2.indd 12 2/20/06 4:00:06 PM Nuclear fission occurs when the nucleus of a uranium atom is hit with a neutron The nucleus breaks, releasing more neutrons These neutrons hit nuclei of other uranium atoms, beginning a chain reaction and releasing energy! Nuclear Energy The nucleus of an atom contains two types of particles, protons and neutrons The energy that holds them together inside the nucleus is called nuclear energy Nuclear energy can be released in two ways, by fission or fusion Nuclear fission is the breaking apart of one nucleaus into two parts Large atoms, such as uranium atoms can break easily When the split occurs a large amount of energy is released and a series of reactions take place This is called a chain reaction Chain reactions are used in power plants to create electricity Nuclear fusion can produce even more energy than fission However, scientists have not yet figured out a way to safely control fusion reactions Why can’t we use nuclear fusion as a reliable energy resource? 13 CXECA08ARD6061-2.indd 13 2/20/06 4:00:08 PM Nuclear waste produced by nuclear fission reactions is dangerous It must be stored in protected places Nuclear Energy Plants Nuclear energy plants are very expensive to build Yet, once built they are inexpensive to run, because uranium cost less than fossil fuels However, like fossil fuels, the use of nuclear energy has environmental costs These plants release heat into the air which can be damaging They produce a waste that goes through a process called radioactive decay Radioactive decay is the process in which one element is transformed into another 14 CXECA08ARD6061-2.indd 14 2/20/06 4:00:14 PM Radioactive waste materials must be stored in special facilities The radiation from the deacy can cause illness in organisms What is a benefit to using nuclear energy plants? Like fossil-fuel electric plants, nuclear plants generate heat The heat is used to spin turbines and make electricity Nuclear reactor core Control rods Generator Turbine Condenser Heat exchanger 15 CXECA08ARD6061-2.indd 15 2/20/06 4:00:24 PM Sun, Wind, and Water Solar energy can be collected by using solar cells A solar cell becomes electrically charged when it absorbs light Solar cells can supply electricity to places that are far from electrical lines Solar energy is free, but solar cells are expensive to make Many places cannot rely on the sun for energy because they not get enough sunny days Solar technology is inefficient Wind turbines are less expensive to make than solar cells but can also be an inefficent energy source If the wind is not blowing the turbines on a certain day, electricity cannot be produced Water is stored behind the dam A hydroelectric dam produces electricity When the gates of the dam are open, water pours through a turbine The moving water turns the turbine, which is connected by a shaft to a generator 16 CXECA08ARD6061-2.indd 16 2/20/06 4:00:30 PM Water is another renewable energy source like the sun and wind Electrical energy produced by moving water is called hydroelectric energy Most hydroelectric energy comes from dams across rivers Dams have environmental costs They change upstream habitats and decrease sediment This can cause land to be less fertile and shrink Which is the most reliable source of energy, the sun, wind, or water? Wires carry the electric current to homes and businesses The rotation of a magnet produces electric current in the coils of the generator 17 CXECA08ARD6061-2.indd 17 2/20/06 4:00:37 PM Geothermal Energy Energy that is generated from below Earth’s surface is called geothermal energy Recently technology has been created to use geothermal energy One type of technology is deep-well drilling Wells are dug deep into the ground Hot steam or ground water is pumped up to the surface The heat is used to turn turbines which is connected to electric generators Geothermal energy is a clean energy source However these plants are only built near hot springs or hot spots The waste from these wells can cause air pollution How is a geothermal energy plant similar to other kinds of energy plants? A geothermal heat pump takes advantage of Earth’s crust temperature to heat and cool a home During winter, cold air from above ground is pumped below ground, where the air is warmed The warm air is then pumped up into the house During summer, warm air from above ground is pumped below ground, where the air is cooled Then the cool air is pumped into the house 18 CXECA08ARD6061-2.indd 18 2/20/06 4:00:41 PM Energy Resources Fossil fuels Geothermal energy Solar energy Nuclear energy Biomass Hydroelectric energy Wind energy Review Complete these compare and contrast statements The cheapest from of energy that we use today is is produced in the splitting of a nucleus during nuclear fission is electrical energy produced by moving water Energy generated from hot water or steam below Earth’s surface is called 19 CXECA08ARD6061-2.indd 19 2/20/06 4:00:46 PM GLOSSARY fossil fuel [FAHS•uhl FYOO•uhl] Coal and petroleum that were formed from ancient organisms geothermal energy [jee•oh•THER•muhl EN•er•jee] Energy produced from within Earth’s crust hydroelectric energy [hy•droh•ee•LEK•trik EN•er•jee] Electricity produced by moving water nonrenewable resource [nahn•rih•NOO•uh•buhl REE•sawrs] A resource that cannot be replaced quickly if it is used up nuclear energy [NOO•klee•er EN•er•jee] The energy that binds protons and neutrons inside an atom’s nucleus radioactive decay [ray•dee•oh•AK•tiv dee•KAY] The process by which the nuclei of atoms give off particles renewable resource [rih•noo•uh•buhl REE•sawrs] A resource that can be replaced quickly through natural processes 20 CXECA08ARD6061-2.indd 20 2/20/06 4:01:09 PM Think About the Reading What can you to help you remember what you have learned about our resources? What questions you have after reading this book? How can you find the answers to your questions? Copyright © by Harcourt, Inc All rights reserved No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publisher Requests for permission to make copies of any part of the work should be addressed to School Permissions and Copyrights, Harcourt, Inc., 6277 Sea Harbor Drive, Orlando, Florida 32887-6777 Fax: 407-345-2418 HARCOURT and the Harcourt Logo are trademarks of Harcourt, Inc., registered in the United States of America and/or other jurisdictions Hands-On Activity Think about what you have learned about classifying material resources Create these charts and explain how they compare and contrast Make a chart of renewable resources that you use in your daily life Make a chart of the non-renewable items that you use in your daily life Printed in the United States of America ISBN-13: 978-0-15-349212-9 ISBN-10: 0-15-349212-0 10 179 15 14 13 12 11 10 09 08 07 06 If you have received these materials as examination copies free of charge, Harcourt School Publishers retains title to the materials and they may not be resold Resale of examination copies is strictly prohibited and is illegal Possession of this publication in print format does not entitle users to convert this publication, or any portion of it, into electronic format CXECA08ARD606_LLR_CVa.indd 4-5 School-Home Connection Discuss with a family member different energy resources that you have learned about Research with your family whether you live near a type of energy plant that you have studied What kind of plant is it? 2/20/06 4:48:51 PM ... in your daily life Printed in the United States of America ISBN -13 : 978-0 -15 -349 21 2 -9 ISBN -10 : 0 -15 -349 21 2 -0 10 17 9 15 14 13 12 11 10 09 08 07 06 If you have received these materials as examination... in your daily life Printed in the United States of America ISBN -13 : 978-0 -15 -349 21 2 -9 ISBN -10 : 0 -15 -349 21 2 -0 10 17 9 15 14 13 12 11 10 09 08 07 06 If you have received these materials as examination... Resources Lessons 1? ? ?2 Lesson How Are Natural Resources Classified? .2 Lesson How Do Energy Resources Differ? 10 Visit The Learning Site! www.harcourtschool.com CXECA08ARD60 61- 2. indd