Nghe TOEFL

🎧 Bản ghi âm

Listen to part of a lecture in an environmental science class. The professor is discussing the concept of 'urban heat islands'. Professor: Today, let's talk about urban heat islands, a phenomenon where cities are significantly warmer than surrounding rural areas. This occurs mainly because of the materials used in urban construction. Asphalt and concrete absorb and retain heat from the sun during the day and release it slowly at night. In contrast, natural surfaces like soil and vegetation reflect more sunlight and cool down faster. Another factor is the lack of vegetation. Trees provide shade and release moisture through transpiration, which cools the air. But in cities, we've replaced many green spaces with buildings and roads. Additionally, waste heat from vehicles, air conditioners, and industrial processes adds to the overall temperature. So, what can be done? One solution is to plant more trees and create green roofs. Another is to use cooler materials, like reflective paints on rooftops. These measures can reduce a city's temperature by a few degrees, improving comfort and reducing energy use for cooling. However, implementing them requires city planning and community effort.