A lava lamp is a decorative lighting fixture that contains a special liquid and wax. When the lamp is turned on, a light bulb at the base heats the wax, causing it to rise and fall in mesmerizing patterns. This movement creates a soothing visual effect that many people find relaxing. The design of a lava lamp typically features a glass container filled with colored liquid and a wax substance. The combination of heat and density differences between the wax and liquid allows the wax to form blobs that float and change shape, making it a popular item for home decor and ambiance.