Dry cells

Dry cells are portable electric cells that produce electricity using chemicals held in a moist paste rather than a free-flowing liquid.

• The paste electrolyte makes a dry cell safer and easier to carry than a cell containing liquid, because it is much less likely to spill.
• Inside, chemical reactions cause electrons to move from the zinc container (negative terminal) through an external circuit towards the carbon rod (positive terminal). This electron flow is electric current.
• A torch battery is a familiar example. When the switch is closed, the dry cell provides energy for current to pass through the bulb, making it glow.
• “Dry” does not mean completely without moisture. The electrolyte must be moist so that charged particles can move within the cell and keep the chemical reaction going.
• Ordinary dry cells are usually single-use: when their reactant chemicals are used up, they cannot provide useful current. Used cells should be collected for proper recycling rather than thrown carelessly into waste.