Which will cool down quicker at kettle of water at 100 degrees or one at 70 degrees?

The kettle of water at 100 degrees Celsius will cool down quicker initially because it is at a higher temperature, and the rate of heat loss is generally greater when there is a larger temperature difference between the water and its surroundings. This phenomenon is described by Newton's Law of Cooling, which states that the rate of heat loss of a body is proportional to the difference in temperature between the body and its environment. However, as the temperatures approach equilibrium, the rate of cooling will slow down for both kettles.