Question

1. which is the best material to use as the floor for a passive solar home?

material	initial temperature	temperature after 5 mins of heat	temperature after 5 mins of cooling
concrete	23 c	25 c	25 c
wood	23 c	33 c	25 c

a) dirt
b) concrete
c) wood

Explanation:

For a passive solar home, the floor material should store heat (increase temp when heated) and retain it (stable temp when cooling). Analyze each:

• Dirt: Small temp rise (20→21°C), stable but low heat storage.
• Concrete: Initial 23°C, rises to 25°C (heat storage) and stays 25°C (heat retention).
• Wood: Rises to 33°C (high temp) but cools to 25°C, so it loses heat easily, poor retention.

Concrete balances heat absorption (moderate rise) and retention (stable after cooling), making it better for passive solar (stores heat during sun, releases slowly).

Answer:

b) Concrete