Ductile describes materials that can be stretched, pulled, or drawn into thin shapes without breaking. Gold is remarkably ductile: a single ounce can be drawn into a wire over fifty miles long. Copper's ductility makes it perfect for electrical wiring, since it can be pulled into long, thin strands that bend around corners without snapping.

Picture a blacksmith heating metal until it becomes soft enough to hammer and stretch into new forms. Brittle materials like glass or ceramic shatter under that kind of stress, but ductile materials cooperate.

Scientists distinguish ductility from malleability, though the two are related. Malleable materials can be hammered flat or shaped by compression, while ductile materials can be stretched lengthwise. Lead is highly malleable but not very ductile. Gold happens to be both.