人教版2020新 高一必修一 Unit4 Natural-disasters reading and thinking .ppt

1、 Natural disasters April 17, 2012 We can see many disasters occurring at home and abroad in recent years, huge damage have been made either to the environment or to our human lives. Those natural disaster urge us to reconsider our beliefs and behavior toward our mother nature. Part One : What are na

2、tural disasters? Part Two: How many types of natural disasters can you list? Part Three: Describe some natural disasters beside us ？ Part Four :How to prepare for natural disasters? Let us talk something about natural disasters. Part One : What are natural disasters？ A natural disaster is a threat o

3、f a naturally occurring event that will have a negative effect on people or the environment. Effect of Natural Disasters ： Death, Damage to property, Homelessness， Population migration, Economic impact， Destruction of infrastructure . The resulting loss depends on the vulnerability of the affected p

4、opulation to resist the hazard, also called their resilience. Natural hazards= things happen in nature that have the potential for a lot of damage. Natural disasters= terrible things do happen and normal life is interrupted. A natural disaster is the effect of earths natural hazards Natural disaster

5、s VS Natural hazards Man made Calamity VS Natural disasters Man made Calamity =Caused by humans. Such as Traffic accident, Plane crash, Terrorist attack Natural disaster=A disaster caused by natural forces rather than by human action . Such as Earthquakes ,Volcanic eruptions, Floods, Droughts, Tsuna

6、mis , Hurricane. . Part Two: How many Types of Natural Disaster can you list? Geological （地质）（地质）disasters Avalanches（雪崩） ,Earthquakes ,Volcanic eruptions, Mudflow/ Debris flow（泥石流）, Landside（滑坡） ,Sand storm Hydrological（水文）（水文） disasters Floods/Rainstorm, Tsunamis （海啸） Meteorological （气象）（气象）disast

7、ers Blizzards（暴风雪）/ Snow storm , Hailstorms/ Hailstone （冰雹） , Thunder and Lighting, Droughts , Heat waves, Tornado(龙卷风) Hurricane/Typhoon/Tropical（热带） Storm/Cyclonic （气旋）Storm Fire disasters Wildfire/ forest fire Health disasters Epidemics Space disasters Solar flares（太阳耀斑） ,Gamma ray burst（伽玛射线爆发）

8、Part Three: Describe Some Natural Disasters beside us ？ Earthquake Earthquakes are among the most powerful events on earth,and their results can be terrifying. An earthquake is the result of a sudden release of energy in the Earths crust that creates seismic waves. At the Earths surface, earthquakes

9、 manifest themselves by vibration, shaking and sometimes displacement of the ground. The vibrations may vary in magnitude. Earthquakes with magnitude 3 or lower are mostly not awared ( we may not feel it), but earthquakes with magnitude 7 can cause serious damage over large areas. Earthquakes by the

10、mselves rarely kill people or wildlife. It is usually the secondary events that they trigger, such as building collapse, fires, tsunamis (seismic sea waves) and volcanoes, that are actually the human disaster. Many of these could possibly be avoided by better construction, safety systems, early warn

11、ing and evacuation planning. wenchuan earthquake On May 12th,2008, a deadly earthquake that measured at 8.0 magnitude occurred in Sichuan Province and killed at least 68,000 people. Wenchuan, a small city, was destroyed by the earthquake. Many people were buried underground. Many houses were collaps

12、ed The army comes to help people who were buried Our Prime Minister went to the front line at the first time. God bless china Much distress regenerates a nation. Avalanche（雪崩） The sudden fall or slide of a large mass of material down the side of a mountain. Avalanches may contain snow, ice, rock, so

13、il, or a mixture of these materials. Avalanches can be triggered by changes in temperature, by sound vibrations, or by vibrations in the earth itself. Landside（滑坡）/ Mudflow/ Debris flow(泥石流) A landslide is a disaster closely related to an avalanche, but instead of occurring with snow, it occurs invo

14、lving actual elements of the ground, including rocks , trees, parts of houses, and anything else which may happen to be swept up. Landslides can be caused by earthquakes, volcanic eruptions, or general instability in the surrounding land. Mudflows , are a special case of landslides, in which heavy r

15、ainfall causes loose soil on steep terrain to collapse and slide downwards A debris flow is a moving mass of loose mud, sand, soil, rock, water and air that travels down a slope under the influence of gravity. Volcano/volcanic eruption Volcano : an opening in the earths crust from which molten lava,

16、 rock fragments, ashes, dust, and gases are ejected from below the earths surface, and then a mountain formed from volcanic material ejected from a vent in a central crater Volcanoes are described as active, dormant, or extinct. volcanic eruption - the sudden occurrence of a violent discharge of ste

17、am and volcanic material. Sand storm Tsunami（海啸） Tsunamis can be caused by earthquakes, volcanoes, or landsides under the ocean. Waves grow taller as they reach the coast. On the December 26, 2004, a strong earthquake hit the Indian Ocean. The earthquake and tsunami cause over 300 000 deaths and man

18、y injuries, and millions of people are made homeless. Indian Ocean Tsunami: on Dec. 26, 2004. Flood/Rainstorm A flood is an overflow of an expanse of water that submerges land. The flood is Most common natural hazard, usually Cause by heavy rain or by snow melting and the rivers burst their banks an

19、d overflow The 1998 Yangtze River Floods, in China, left 14 million people homeless. Drought If a particular area has no rainfall or less rain than normal for a long period of time is called drought. It is not only lack of rainfall that causes drought. Hot dry winds, very high temperature and evapor

20、ation of moisture from the ground can result in conditions of drought. Do you believe there used to be a lake? In 2006, Sichuan Province China experienced its worst drought in modern times with nearly 8 million people and over 7 million cattle facing water shortages. It is said that its the most ser

21、ious drought since PRC has been founded. Premier wen comes to the drought- stricken area. Several kids are playing on the vast expanses of cracked earth. Snow storm/ blizzard(暴风雪) Blizzards are severe winter storms characterized by low temperature, strong winds, and heavy snow. Tornado(龙卷风龙卷风) A tor

22、nado is a violent, dangerous, rotating column of air that is in contact with both the surface of the earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. They are often referred to as a twister or a cyclone. During a tornado trees can be uprooted, buildings can be destroyed

23、 and cars can be overturned typhoon / Hurricane/Cyclonic storms/ Tropical（热带）Storm Cyclone, tropical cyclone, hurricane, and typhoon are different names for the same phenomenon a cyclonic storm system that forms over the oceans. A tropical cyclone is a storm system cup characterized by a low-pressur

24、e center and numerous thunderstorms that produce strong winds and heavy rain. Hailstone（冰雹） A storm with hail Hailstorms are rain drops that have formed together into ice Heat Wave（热浪） A heat wave is a prolonged period of excessively hot weather, which may be accompanied by high humidity . Thunder a

25、nd Lighting Wildfire/ forest fire Epidemics An epidemic is an outbreak of a contractible disease that spreads at a rapid rate through a human population. A pandemic is an epidemic whose spread is global. There have been many epidemics throughout history. The 2002 SARS pandemic Part Four :How to prep

26、are for natural disasters? As we know natural disasters cause by natural forces rather than by human action . Are they just caused by natural forces? I dont think so . I more believe it is caused by long-term human impact. Scientists proved to us those natural disasters are rarely caused by pure nat

27、ural factor, especially in nowadays human activities are more frequent. Because human has immensely demand , the destruction they made increased the frequency and extent of natural disasters. As a resident on earth, We should always keep in mind the earth is the only home we rely on. we should take

28、the responsibility to protect our mother nature. Perhaps in this way can we minimise or prevent natural disasters. Protect our mother nature Preparing is very important Initiate an emergency response plan. Scientists need to gather information and try to predict what will happen in the future. Gover

29、nment must be prepared to provide for peoples basic needs if there is a natural disaster . Government should plan for what to do in the days and weeks following the disaster, and enable people to return to normal life after the damage is done. In this way can we limit the damage they cause. What can

30、 we do? Remain calm and patient when natural disasters strikes (easier said than done). When the evacuation order comes, heed the order immediately ,go to safe place. (this is important to avoid a bad situation if possible). If you cant evacuate. Find a safe place to wait for rescue . Knowledge Means Survival“. Understand some of the knowledge of first aid and survival skills can help you better prepare . Think you for your watching!