How is Celsius scale different to the one today?

The Celsius scale, developed by Anders Celsius in 1742, originally defined 0 degrees as the boiling point of water and 100 degrees as the freezing point. This was later reversed to the current system, where 0 degrees Celsius is the freezing point of water and 100 degrees is the boiling point at standard atmospheric pressure. The revised scale is now widely used in scientific and everyday contexts, providing a clear and consistent temperature reference.