Chapter 14, Problem 20Q

To determine

To Explain:

why the floor of a house on a foundation under which the air can flow if often cooler that a floor that rests directly on the ground.

Answer to Problem 20Q

Solution:

The floor of a house on a foundation under which the air can flow is often cooler than a floor that rests directly on the ground because the thermal energy from the floor will be heating the air instead of the concrete.

Explanation of Solution

The ground heats the air above it. In case of a floor which rests on a foundation, this air is moved away by wind currents and replaced with colder air. This makes floor of the house cooler.

In case of the floor that rests directly on the ground, the heat from the ground directly warms the concrete floor of the house.