การฟัง TOEFL

🎧 บทถอดเสียง

Narrator: Listen to part of a lecture in an environmental science class. Professor: Today we’re going to talk about urban heat islands. Now, you might think that cities are just warmer because of all the concrete and asphalt, but there’s more to it. The main cause is the replacement of natural surfaces, like soil and vegetation, with materials that absorb and retain heat. During the day, buildings and roads soak up solar radiation, and at night, they release it slowly, keeping the city warmer than the surrounding countryside. But here’s an interesting twist: not all cities have the same intensity of heat island effect. Factors like city size, population density, and even the local climate play a role. For example, a city in a dry, sunny region might experience a stronger effect than one in a humid area, because water vapor in the air can trap heat and also promote cloud cover, which reduces solar radiation. So, when we think about mitigating this, we often consider green roofs and reflective surfaces, but the effectiveness of these measures depends on the specific urban environment. Does anyone have a question?