🔍 Key Concepts

• Annealing vs hardening of metals • Effect of rapid cooling vs slow cooling on metal softness and brittleness • Which methods (water, oil, air) are typically used for quenching/hardening rather than softening

💭 Think About

• Is the goal of making a copper gasket to have it hard and springy, or soft and easily conforming to surfaces? • When you heat steel and want to harden it, do you cool it quickly or slowly—and how might copper be treated differently or similarly when the goal is softness? • Which cooling method in the choices is most associated with making metals harder instead of softer?

✅ Before You Answer

• Be clear on the purpose of annealing (what property change we want). • Identify which options involve rapid quenching vs slow cooling. • Eliminate any option that would typically increase hardness or brittleness rather than decrease it.