Indicate the direction of heat flow in each scenario.
| Scenario | Object 1 | Object 2 |
| :------- | :----------------------- | :----------------------- |
| A | Lotion at $27^{\circ} C$ | Skin at $37^{\circ} C$ |
| B | Lasagna at $170^{\circ} C$ | Plate at $20^{\circ} C$ |
| C | Ocean water at $25^{\circ} C$ | Lava at $950^{\circ} C$ |
| D | Eggs at $2^{\circ} C$ | Sidewalk at $80^{\circ} C$ |
Scenario A: $\square$
Scenario B: $\square$
Scenario C: $\square$
Scenario D: $\square$
Answer (1)
Heat flows from a warmer object to a cooler object.
Scenario A: Heat flows from skin to lotion.
Scenario B: Heat flows from lasagna to plate.
Scenario C: Heat flows from lava to ocean water.
Scenario D: Heat flows from sidewalk to eggs.
Explanation
Understanding Heat Flow We need to determine the direction of heat flow in each scenario. Heat always flows from a warmer object to a cooler object. We will compare the temperatures of the two objects in each scenario to determine the direction of heat flow.
Scenario A In Scenario A, the lotion is at 2 7 ∘ C and the skin is at 3 7 ∘ C . Since 27^{\circ}C"> 3 7 ∘ C > 2 7 ∘ C , heat flows from the skin to the lotion.
Scenario B In Scenario B, the lasagna is at 17 0 ∘ C and the plate is at 2 0 ∘ C . Since 20^{\circ}C"> 17 0 ∘ C > 2 0 ∘ C , heat flows from the lasagna to the plate.
Scenario C In Scenario C, the ocean water is at 2 5 ∘ C and the lava is at 95 0 ∘ C . Since 25^{\circ}C"> 95 0 ∘ C > 2 5 ∘ C , heat flows from the lava to the ocean water.
Scenario D In Scenario D, the eggs are at 2 ∘ C and the sidewalk is at 8 0 ∘ C . Since 2^{\circ}C"> 8 0 ∘ C > 2 ∘ C , heat flows from the sidewalk to the eggs.
Final Answer Therefore, the direction of heat flow in each scenario is as follows: Scenario A: From skin to lotion Scenario B: From lasagna to plate Scenario C: From lava to ocean water Scenario D: From sidewalk to eggs
Examples
Understanding heat flow is crucial in many everyday situations. For example, when you hold a cold glass of water on a hot day, heat from your hand transfers to the glass, warming the water and cooling your hand. Similarly, when cooking, heat transfers from the stove to the pot, cooking the food inside. This principle is also used in engineering to design efficient heating and cooling systems.
