📢فایل صوتی #ریدینگ اول #زبان_عمومی #آزمون_دکتری #رشته_انسانی سال 1398 آشنایی با #تلفظ صحیح➕#لغات A common phenomenon in arid regions of the world is the whirling vortex called the "dust devil." Although they resemble tornadoes, dust devils are generally much smaller and less intense than their more destructive cousins. Most dust devils are only a few meters in diameter and reach heights no greater than about 100 meters. Further, these whirlwinds are usually short-lived microscale phenomena: most form and die out within minutes. Unlike tornadoes, which are associated with clouds, dust devils form on days when clear skies prevail. Further, these whirlwinds form from the ground upward, exactly the opposite of tornadoes. Because surface heating is critical to their formation, dust devils occur most frequently in the afternoon, when surface temperatures are highest Dust devils form when the hot surface of the earth warms the air above it. When the air near the Surface considerably warmer than the air a few tens of meters overhead, the layer of air near Earth's surface becomes unstable. In this situation, warm surface air begins to rise, causing air near the ground to be drawn into the developing whirlwind. A light wind will start this rising air to rotate, and once the rotation has begun, it becomes faster due to the same physical principle that causes ice-skaters to spin faster as they pull their arms closer to their body. As the inwardly spiraling air rises, it carries sand, dust, and other loose debris tens of meters into the air. It is this material that makes a dust devil visible Occasionally, dust devils form above ground covered with vegetation. Under these conditions, the vortices may go undetected unless they interact with objects at the surface. 📌Phenomenon - پدیده Arid - خشک Whirling - چرخشی Vortex - گردباد Dust devil - گردباد خاکی Tornadoes - گردبادها Destructive - ویرانگر Cousins - هم‌خانواده‌ها Diameter - قُطر Heights - ارتفاعات Whirlwinds - گردبادها Short-lived - کوتاه‌عمر Microscale - مقیاس میکرو Phenomena - پدیده‌ها Form - شکل‌گیری Prevail - غالب شدن Surface heating - گرمایش سطحی Formation - تشکیل Frequently - مکرراً Afternoon - بعدازظهر Temperatures -دما Warms - گرم می‌کند Considerably - به‌طور قابل توجهی Unstable - ناپایدار Whirlwind - گردباد Developing - در حال توسعه Light wind - باد ملایم Principle - اصل Ice-skaters - اسکیت‌بازان یخی Spin - چرخش Inwardly spiraling - چرخش داخلی Debris - آوار Visible - قابل‌مشاهده Occasionally - گهگاهی Vegetation - پوشش گیاهی Conditions - شرایط Undetected - غیرقابل شناسایی Interact - تعامل Objects - اشیاء ━═━━⊰❀🦋❀⊱━━═━ #آموزش_زبان_انگلیسی با #دکتر_مصطفوی عضو شوید👇 @drmostafavi

📢فایل صوتی #ریدینگ اول #زبان_عمومی #آزمون_دکتری #رشته_انسانی سال 1398 آشنایی با #تلفظ صحیح سال #قرائت_متن: بهمن ماه سال 1401 #ویس_ادمین ━═━━⊰❀🦋❀⊱━━═━ #آموزش_زبان_انگلیسی با #دکتر_مصطفوی عضو شوید👇 @drmostafavi