* Open System: An open system exchanges both matter and energy with its surroundings.

* Melting Ice:

* Matter exchange: The ice absorbs heat energy from the environment (matter exchange). This causes the ice to melt and change state from solid to liquid (water), which is then released back into the surroundings.

* Energy exchange: The ice absorbs heat energy from the environment (energy exchange).

Therefore, because of the exchange of both matter and energy with the surroundings, the melting of a block of ice is considered an open system.