What is the perfect Ice Cube?

Question

I have a freezer with -25°C temperature and Soda with +30°C.

What is the ice-cube-sized material I can put in the freezer that can bring my glas of soda to the lowest temperature?

Are e.g. saltwater icecubes better than pure water cubes?

extra points for not waterifying my soda :)

Why not simply put your soda in the fridge? This is an ill-posed question because there are too many open ends. Also, what concept are you trying to explore? What do you mean by "lowest temperature? 0 K? — Bill N, Jul 29 '15 at 14:05
Ok, good point. I am looking for the best material. (edited fridge -> freezer) — wuschelhase, Jul 29 '15 at 14:13
My guess would be an ice cube sized black hole would bring your glass of soda to the lowest temperature, but good luck drinking it. — Rick, Jul 29 '15 at 14:25
In other words - you are not looking for ice: you want the material with the greatest heat capacity. Of course materials that exhibit a phase transition (like ice->water) have a very large associated latent heat of fusion and beat any "regular" solids. There are "water in plastic" ice "cubes" that have the heat capacity without the watering-down component. — Floris, Jul 29 '15 at 14:25
related question: http://physics.stackexchange.com/q/3723/26969 — Floris, Jul 29 '15 at 14:28

Floris · Accepted Answer · 2015-07-29T14:53:34.057

If you look at this table you will see that water, even without the phase transition, actually has the highest volumetric heat capacity of any of the substances listed (absent any phase transition materials).

This means that an ice cube is indeed the best you can do for cooling down your drink. Even when you take account of the heat of fusion, water is better than most materials. The only material that comes even close is formic acid with a value around 250 J/g (ice is 334 J/g). Of course your drink will taste HORRIBLE when that dissolves - formic acid is the stuff in some insect bites/plant stings.

If you really want to get as cold as possible, you want to lower the melting point of your water (for example by adding salt) until it's just above the coldest temperature your freezer can achieve. Put that liquid inside a thin-walled container. Put plenty of those cubes in your drink; you will be able to cool the drink all the way to the melting point of your "salt ice".

I found such cubes online (no commercial relationship with this site... just found it with Google).

I didnt put much thought into it, but wouldnt "ice" cubes out of say copper outperform that? — Bort, Jul 29 '15 at 15:07
@Bort - surprisingly no, not at all. The volumetric heat capacity of copper is 3.45 J/cc/K, while for water it is 4.2 J/cc/K . Plus, when ice melts it absorbs 334 J/g. So every gram of ice that melts can cool ~75 ml of water by one degree. — Floris, Jul 29 '15 at 15:13
related: http://physics.stackexchange.com/questions/28255/greatest-volumetric-heat-capacity (and thanks @Floris ) — Bort, Jul 29 '15 at 15:31

score 1 · Answer 2 · answered Jul 29 '15 at 14:42

You can try ice cubes made of soda for having only soda. You can try having spherical cubes instead of small cubical ones, which take more time to melt.

Or else try adding some salt to the water and freezing it. It reduces the freezing temperature of ice which makes the ice freeze faster and melt slower.(But 10 gm of salt in 10 litres make a change of 0.1 Celsius change)

You can also try with different shapes of trays which you use, a tray with less surface area, the less surface area exposed, the less it will melt.

Ice made in plastic trays and silicone molds freezes from all sides, trapping impurities and making for a weaker cube. Using an open insulated cooler, which forces a top-down freeze, making a dense, slow-melting ice.

What is the perfect Ice Cube?

2 Answers2