5.12 describe the Kelvin scale of temperature and be able to convert between the Kelvin and Celsius scales

The kelvin temperature scale uses absolute zero as a starting point.
Absolute zero is 0 Kelvin.

Absolute zero is -273°C

0 kelvin = -273°C

273 Kelvin = 0°C

1 Kelvin = -272°C

274 Kelvin = 1°C

Above are examples of how to convert between the two, as you can see I have just just a solving equations method to work out different values (eg what you do to one side you must add to the other.)