Temperature stratification is caused by which of the following?

• A. Convection
• B. The tendency of light, warm air to rise
• C. Uninsulated floors over unheated spaces
• D. All of the above

Answer: (D)

Temperature stratification occurs when buoyancy forces and limited vertical mixing create a vertical temperature gradient in a space. Warm air is less dense, so it tends to rise, producing warmer air near the ceiling and cooler air near the floor. This buoyancy-driven rise is the core reason you see stratification. Convection—the movement of air driven by temperature differences—facilitates or limits how well those warmer and cooler layers mix. When convection is weak or impeded, the layers stay separated, intensifying stratification. Uninsulated floors over unheated spaces add another factor: heat escaping downward cools the floor, strengthening the cold layer at the bottom and making the difference between ceiling and floor temperatures more pronounced. Because buoyancy, air movement (convection), and boundary conditions like an uninsulated floor all contribute, temperature stratification arises from all of these factors working together.