1. Slideshow P3: Batteries

2. A simple battery (electrolytic cell). A simple cell has liquid which conducts electricity (an electrolyte) and two conductors (usually metals).

3. The two conductors were a copper cylinder and an iron rod. They fitted in the pot. The electrolyte is believed to have been wine, lemon juice, grape juice or vinegar. The Baghdad battery (from about 2000 years ago).

4. A voltaic pile was invented by Alessandro Volta in 1800. It produced a high voltage and helped scientists to discover new metals. A voltaic pile.

5. This is what a normal (non-rechargeable) battery is like. A zinc–carbon ‘dry’ cell.

6. Rechargeable batteries are very useful. Rechargeable batteries.