1. Think about how surfaces in cities differ from those in the surrounding areas. Why might a central city contain more thermal energy than a farm or forest?

The difference in thermal energy between central cities and surrounding areas like farms or forests can be attributed to several factors: 1. **Urban Heat Island Effect**: Cities often experience the urban heat island (UHI) effect, where urban areas become significantly warmer than their rural surroundings. This is primarily due to the concentration of buildings, roads, and other infrastructure that absorb and retain heat. 2. **Materials and Surfaces**: Urban areas are dominated by materials such as concrete, asphalt, and brick, which have high thermal mass and heat retention properties. These materials absorb heat during the day and release it slowly at night, leading to higher overall temperatures. In contrast, rural areas typically have more vegetation and soil, which can cool the environment through processes like evapotranspiration. 3. **Vegetation**: Farms and forests have a higher density of vegetation, which provides shade and cools the air through evapotranspiration. Trees and plants absorb sunlight and release moisture, helping to lower temperatures. In cities, the amount of green space is often limited, reducing this cooling effect. 4. **Human Activity**: Central cities have higher levels of human activity, including transportation, industrial processes, and energy consumption, all of which generate heat. The concentration of vehicles, machinery, and buildings contributes to the overall thermal energy in urban areas. 5. **Air Pollution**: Urban areas often have higher levels of air pollution, which can trap heat in the atmosphere. Pollutants can absorb and re-radiate heat, contributing to warmer temperatures in cities compared to rural areas. 6. **Building Density and Configuration**: The density and configuration of buildings in cities can create canyons that trap heat and limit airflow, further exacerbating temperature increases. In contrast, rural areas typically have more open space, allowing for better air circulation and cooling. Overall, the combination of these factors leads to central cities retaining more thermal energy compared to farms or forests, resulting in higher temperatures and contributing to the urban heat island effect.