Ice at 273 K (0°C) cools better than water at 273 K because it must first melt, and during melting it absorbs an extra large amount of heat called latent heat of fusion without its temperature rising.

Quick Scoop

  • 273 K = 0°C for both ice and water.
  • Ice at 0°C needs extra energy to change state (solid → liquid).
  • That extra energy is taken from whatever you’re trying to cool, so the cooling is stronger.

Core Idea: Latent Heat

When ice at 273 K melts into water at 273 K, it absorbs a lot of heat just to break the solid structure, without any change in temperature.

This “hidden” energy is the latent heat of fusion, and for ice it is about 3.34 × 10⁵ J per kilogram, which is a huge amount of heat taken from the surroundings.

Water at 273 K does not change its state, so it does not need this extra latent heat.

It can only absorb heat according to its specific heat capacity, which is much less energy than what ice absorbs while melting at the same temperature.

Simple Mental Picture

Imagine you put equal masses of ice at 0°C and water at 0°C into two identical warm drinks.

  1. The ice :
    • First absorbs a large amount of latent heat to melt completely at 0°C.
 * Only after melting will the resulting water warm above 0°C.
  1. The water at 0°C:
    • Starts warming immediately from 0°C upward, no phase change, no latent heat step.

Because the ice has to “spend” so much energy just to melt, it pulls more heat out of the drink overall, so the drink becomes cooler.

Key Points in Bullet Form

  • Both ice and water can be at 273 K (0°C), but their internal energy is different. Ice has less internal energy than water at the same temperature.
  • To turn into water at 0°C, ice must absorb latent heat of fusion from its surroundings.
  • This extra absorbed heat produces a stronger cooling effect than water at 0°C, which does not absorb latent heat.

So, ice at 273 K is more effective in cooling than water at 273 K because it absorbs additional latent heat of fusion while melting, removing more heat from the object being cooled.

TL;DR:
Ice at 273 K cools better than water at 273 K because it must melt first and, in doing so, absorbs a large extra amount of latent heat from its surroundings, giving a stronger cooling effect.

Information gathered from public forums or data available on the internet and portrayed here.