Pick up a metal spoon and a wooden one and leave both in hot water. T metal sp becomes pai to ho within sec, while t wooden han stays comfo for min. The diffe lies in how each material carries energy. In a metal, some electrons are not bound to any particular atom and drift freely through the whole structure, so heat travels as fast as those electrons move. Wood has no such free electrons, and energy must pass slowly from one vibrating molecule to the next.

Type only the missing letters. Each box is one letter, and the number of boxes matches the letters that are missing.