A vacuum pump is a device that removes gas molecules from a sealed volume to create a vacuum. It works by creating a pressure difference, allowing air and other gases to be drawn out. Vacuum pumps are commonly used in various applications, including laboratories, manufacturing, and HVAC systems. There are different types of vacuum pumps, such as rotary vane pumps, diaphragm pumps, and turbo pumps, each designed for specific tasks. They are essential in processes like freeze-drying, packaging, and semiconductor fabrication, where a controlled vacuum environment is necessary for optimal results.