A pH meter is an electronic device used to measure the acidity or alkalinity of a solution. It provides a numerical value on a scale from 0 to 14, where 7 is neutral, values below 7 indicate acidity, and values above 7 indicate alkalinity. The meter typically consists of a probe that is placed in the solution and a digital display that shows the pH reading. These devices are commonly used in various fields, including chemistry, biology, and agriculture. Accurate pH measurements are essential for processes like soil testing, water quality assessment, and laboratory experiments, ensuring optimal conditions for growth and reactions.