Knowledge objective: 1. Understand that the surface of the earth is constantly changing. 2, understand the role of various natural forces on the surface change, understand the impact of human activities on the surface change. Ability goal: be able to use simple tables, graphics, statistics and other methods to organize relevant information. Emotion, attitude and values goal: to educate students about the scientific view of nature, that is, nature is constantly moving and changing. Emphasis and difficulty in teaching: imagine the constant change of the earth's surface and its reasons. Teaching preparation: 1. Prepare pictures and videos of sandstorm weather for students. 2. Relevant data leading to sandstorms, and data of sandstorm weather in China in recent decades. Teaching steps: 1. Show pictures and videos about sandstorms. 2. Look at the picture. What kind of natural disaster did we just see? 3. Discussion: What are the main natural phenomena when sandstorms occur? 4. What harm does sandstorm do to us? Please talk about it. Hazards of sandstorm: (1) soil wind erosion, vegetation destruction and farmland burial. (2) It is harmful to human health and irritates the skin. Eyes, nose and throat can cause allergic reactions. Small pollution particles lead to recurrence of heart disease and lung disease, leading to death. (3) Sandstorms affect traffic on a large scale. 4. Large-scale sand dust forms suspended particles in the air, which is enough to affect the weather and climate, inhibit the formation of clouds, reduce the precipitation rate of clouds, reduce the water resources of the earth and aggravate the drought. Analysis data: China's railways with1.5000 km, highways with 30000 km and irrigation canals with 50000 km have been damaged to varying degrees by sandstorms. In recent years, China suffered direct losses of 54 billion yuan due to sandstorms. What do you think after reading the above information? 6. Why is there a sandstorm? What is the cause of sandstorm? 7. Discussion: Among the basic conditions of sandstorm weather, which conditions are related to human activities? 8. Inquiry: Look at P46 small materials and drawings. What do you find from this table? 9. Combine small data with the above statistics: Why? 10. According to the discussion results, think about it. Whose responsibility and obligation is it to prevent sandstorms? What should humans do to prevent sandstorms? Preventing sandstorms is not a departmental matter, but a matter for all mankind, and everyone has the responsibility and obligation. (1) Planting trees and establishing a good ecological barrier.
(2) Establishing shelter forests to prevent the movement of soil and dust; (3) Planting flowers and trees in the city to increase the green area; (4) Scientific grazing to protect the farm 1 1. So, what can we primary school students do? Summary of discussion: 1. Various forms of publicity. 2 handwritten newspapers, proposals, publicity slogans, etc.