[chris (OP)]

Gene got in touch today with this question for us to ponder:

If you have two glasses of liquid and all other factors are equal, will a glass containing 12 ice cubes cool the liquid faster and to a lower temperature than a glass containing  8 ice cubes?

What does everyone think?

[Bored chemist]

Yes.
Crushing the ice- say by  putting it in a plastic bag + hitting it with a hammer- before you put it in the drink will also make it cool the drink faster.

[chris (OP)]

Yes.
Crushing the ice- say by  putting it in a plastic bag + hitting it with a hammer- before you put it in the drink will also make it cool the drink faster.

Can you also explain why please...

[Bored chemist]

Yes.
Crushing the ice- say by  putting it in a plastic bag + hitting it with a hammer- before you put it in the drink will also make it cool the drink faster.

Can you also explain why please...

I could, but I left it as "an exercise for the interested reader"
:-)

I wondered if Gene  would like to speculate on it.

[chris (OP)]

Bored chemist is playing hard to get! Would anyone else like to help out...?

[yor_on]

more surfaces?

[chris (OP)]

When the ice melts, the resulting liquid volume must share the thermal energy of the two former entities; because the ice is at a lower temperature than the drink liquid, the resulting final temperature must be lower than the liquid temperature but warmer than the ice temperature. So, the more ice that is added, the closer to the ice temperature the resulting temperature will be.

What determines how quickly this happens is the rate at which the liquid can share its energy with the ice. This, in turn, is determined by how quickly the ice particles can interact with the liquid particles, which is proportional to the surface area.

Crushing the ice exposes large amounts of surface area to the liquid, so that the rate of energy exchange is high, so the rate of temperature change - aka cooling of the drink - is faster. 

But will the drink overflow once the ice melts... that's the next question...