牛津译林版(2020)必修第三册 unit 2 Welcome to the unit ppt课件.pptx

Unit 2Natural disasters,Nature is kind of a loving mother, but also a butcher in cold blood. - Victor Hugo,In this unit, you are going to:,read two news reports about how disaster preparation has helped save lives;continue writing a story about a family caught in a natural disaster;read an excerpt from a novel about a famous volcanic eruption;make an information folder about rescue methods.,get to know what are natural disasters.get to know some typical natural disasters.watch the video and discuss the following questions. a How much do you know about the natural disasters in the video? b What other natural disasters do you know about?,Natural disasters are extreme, sudden events caused by environmental factors that injure people and damage property.,What are natural disasters?,Top 10 Natural Disasters,1. Hurricane,2. Earthquake,3. Tornado,4. Volcanic eruption,5. Tsunami,6. Flood,7. Wildfire,9. Avalanche,10. Landslide,Natural disasters are terrible reminders of the power of nature. Watch the video and finish the following exercises.,Plates moving underground can cause an earthquake, which is _ of the earths surface.When a volcano erupts, _, volcanic ash and even rocks escape through a large opening at the top.A large amount of _ falling down a hill or mountain is called a landslide.,Discuss the following questions.,1 How much do you know about the natural disasters in the video?2 What other types of natural disasters do you know about? 3 What natural disasters in history have you heard about?,Structure(Name): other type of natural disaster that I know about is.(Reason) :.(Result): .,Natural disasters,pestsinsects,tsunami,tornado,drought,sandstorm,typhoon,forestfire,flood,and more ,Earthquake, any sudden shaking of the ground caused by the passage of seismic waves through Earths rocks. Seismic waves are produced when some form of energy stored in Earths crust is suddenly released, usually when masses of rock straining against one another suddenly fracture and “slip.”,Volcanic eruptions happen when lava and gas are discharged from a volcanic vent. The most common consequences of this are population movements as large numbers of people are often forced to flee the moving lava flow. Volcanic eruptions often cause temporary food shortages and volcanic ash landslides called Lahar.,Landslide, also called landslip, the movement downslope of a mass of rock, debris, earth, or soil (soil being a mixture of earth and debris). Landslides occur when gravitational and other types of shear stresses within a slope exceed the shear strength (resistance to shearing) of the materials that form the slope.,other types of natural disasters,Extreme temperatures caused by a heat wave or cold wave are one of many climatological hazards. A heat wave increases the temperature in a certain region and pushes the human body beyond its limit. The same is the case with a cold wave that is accompanied with heavy snowfall and extreme cold, which may lead to hypothermia.,Hurricanes refer to a closed circulation system in the atmosphere that consists of strong winds and low pressure. The winds rotate clockwise in the southern hemisphere and counter clockwise in the northern hemisphere. A hurricanes is usually characterized by a low-pressure center with strong winds and spiral rain bands.,A sandstorm is also known as the dust storm, which is a strong wind that blows across the arid and semi-arid regions. It causes soil erosion and it occurs due to the poor management of dry land and over-grazing of vegetation.,An ice storm is a form of winter storm wherein cold and freezing rain is experienced. Ice storm is a natural disaster, which can cause damages and health hazards to mankind and livestock.,1. Why do the natural disasters break out more often?2. What can we do to reduce the possibility of natural disasters such as fire?3. What do you think of the first sentence natural disasters are terrible reminders of the power of nature?4. Are natural disasters closely connected with man-made disasters? Can you give an example?,Write down a short paragraph describing a natural disaster. Your writing should include an example and an ending about what we should do.,