A hydraulic jack is a tool used to lift heavy objects, such as cars or machinery, using the power of liquid pressure. It operates on the principle of hydraulics, where a small amount of force applied to a fluid in a cylinder can create a much larger force in another cylinder. This makes it easier to lift heavy loads with minimal effort. These jacks are commonly found in garages and workshops, often used alongside tools like wrenches and safety stands. They come in various sizes, from small bottle jacks to larger floor jacks, making them versatile for different lifting tasks.