🔍 Key Concepts

• Second Law of Thermodynamics and the natural direction of heat flow • Relative thermal conductivity of metals like copper and steel • How phases of matter (gas vs liquid vs solid) generally affect heat transfer

💭 Think About

• Think about what happens when you place a hot object in a cold room: which way does heat naturally move without any external work? • Between common metals on board ships, which is usually chosen for efficient heat exchangers: copper or steel, and why? • Compare how tightly packed the molecules are in gases versus liquids—how does that affect their ability to conduct heat?

✅ Before You Answer

• Verify which direction spontaneous heat flow takes according to basic thermodynamics. • Recall which material, copper or steel, is commonly used when high thermal conductivity is desired. • Consider whether gases or liquids normally have higher thermal conductivity under similar conditions.