Weather problem
Disadvantages: When encountering a "sandstorm", the driver's master can't see the road clearly and is prone to traffic accidents;
(2) According to the causes of sandstorms, we can know that sandstorms are caused by people cutting down trees excessively.
Vegetation is destroyed, forming a dry desert, and the rotation is blown by strong winds, and the rotation floats all over the sky.
Answer: method: it is forbidden to cut down trees and conserve water and soil; Truth: Tree turf can keep water and soil and prevent wind;
(3) According to the cause of sandstorm, a hair dryer can be used to represent strong wind.
Insert a note in the sand to represent grass, insert a pencil in the sand to represent trees,
Scheme: firstly, dry the spun yarn without pencil and paper with a hair dryer and observe the phenomenon;
Phenomenon: it can be seen that sand characters are easily blown everywhere; Then use a hair dryer to blow the spun yarn with pencil and paper.