Volatile data is data that gets lost when a system loses power or is turned off. It's stored in a device's random access memory (RAM), which requires a constant power source to retain information. When the device is powered off, the data in RAM is not saved and is therefore lost. This is in contrast to non-volatile data, which is stored in permanent storage devices like hard drives or solid-state drives. Non-volatile data is not lost when the system is powered off. Volatile data can be crucial in digital forensics and incident response, as it can provide valuable information about a system's state and activities before power loss. However, it's challenging to capture and analyze because of its temporary nature.