Jacks are mechanical devices used to lift heavy objects, typically vehicles, off the ground. They work by applying force through a lever or hydraulic system, allowing users to raise or lower items safely. Common types of jacks include floor jacks, scissor jacks, and bottle jacks, each designed for specific lifting tasks. These tools are essential for various applications, such as changing a tire or performing maintenance on a vehicle. Proper use of jacks ensures safety and efficiency, making them a vital part of any mechanic's toolkit or automotive repair shop.