Explains how batteries convert chemical energy into electrical energy and how they power so many devices. Contents: Battery power! -- Chemical energy -- What's in the chemicals? -- Electrodes -- Electrolytes -- Completing the circuit -- Kinds of batteries -- A short history -- Recycle it! Interest Level: 3-6 Reading Level: 7.4 Lexile Measure: 850 Lexile Code: NC (Non-Conforming Text).