Question

Which surface should you set a pot on to keep it hotter for a longer time? a) a smooth glass surface b) a smooth steel surface c) a smooth wood surface d) a rough wood surface

Short answer

Answer: c) a smooth wood surface

Step-by-step solution

Understand the options and their characteristics

We need to determine which surface would keep the pot hotter for a longer time. For this, we need to compare: a) a smooth glass surface b) a smooth steel surface c) a smooth wood surface d) a rough wood surface We should analyze each material's thermal conductivity and the effect of roughness on heat transfer.

Compare material's thermal conductivity

We need to compare the thermal conductivity of each material. Generally speaking: - Glass has a relatively low thermal conductivity. - Steel has a high thermal conductivity. - Wood has a relatively low thermal conductivity. Since we want to keep the pot hotter for a longer time, we should choose a surface with a lower thermal conductivity, such as glass or wood.

Consider roughness on heat transfer

We need to consider how the roughness of the surface affects heat transfer. Rough surfaces have more contact points with the pot, which increases the rate of heat transfer from the pot to the surface. Since we want to minimize heat loss, we should choose a smooth surface.

Combine material and roughness factors

Now we'll combine the effects of material and roughness, which gives us two options: a) a smooth glass surface (low thermal conductivity and smooth) c) a smooth wood surface (low thermal conductivity and smooth)

Choose the optimal surface

Based on the analysis, a smooth surface with low thermal conductivity should keep the pot hotter for a longer time. Out of the given options, both a smooth glass surface and a smooth wood surface exhibit these characteristics. However, wood is a better insulator than glass, so it would be more effective in minimizing heat loss from the pot. So the correct choice is: c) a smooth wood surface.