Common Core 7th Grade ELA Question of the Day

Greening the Roof: How Cities Cool Down

The Problem: Hotter Cities In many cities, summer heat builds up between tall buildings and dark streets. This effect is called the urban heat island. It makes neighborhoods warmer than nearby rural areas. As a result, people use more air conditioners, which increases energy demand and costs. However, cities are not stuck with this problem. They can change how rooftops are used.

Sidebar: Key Term—Urban Heat Island Definition: When an urban area becomes hotter than nearby countryside because surfaces like asphalt and roofs trap heat.

A Growing Solution One idea is the rooftop garden. A rooftop garden places shallow soil and plants on top of a flat roof. Plants add shade and release moisture. Therefore, they cool the air and the roof surface. For example, a school in a crowded downtown area planted low grasses and herbs on its roof. The building stayed cooler, and students began a science club to measure temperature changes.

How It Works Rooftop gardens help in several ways. First, plants block sunlight, so less heat enters the building. Second, water in the soil evaporates, which removes heat from the air. Third, the added soil acts like a blanket. It slows down the flow of heat into the rooms below. A simple maintenance plan keeps the system healthy. It includes checking drains, trimming plants, and adding compost twice a year. These steps create a sequence that supports long-term results.

Caption: A diagram would show layers from top to bottom: plants, soil, filter fabric, drainage layer, root barrier, insulation, and a waterproof membrane.

A Note of Caution Rooftop gardens are not perfect. They add weight to the building, so engineers must check the structure. They also need care, especially during dry weeks; otherwise, plants will fail. Even so, these limits do not erase the benefits. Instead, they suggest that cities should plan ahead. When building owners follow safety checks and a simple watering schedule, rooftop gardens can reduce heat and save energy across a neighborhood. In short, the article explains a problem, shows a solution, and then qualifies that solution with practical limits.