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Use an Aquarium Pump to Freeze Objects Inside Ice Blocks

6a00e553b3da20883401b8d159845d970c-580wiYou can make a clear block of ice using an insulated cooler with the Directional Freezing method. You can also use this method to freeze objects inside of ice blocks including freezing a full-sized bottle inside an ice block.

If you are able to add an aquarium pump to the mix, you can make clear ice from the bottom up without any cloudy parts at the end; a method that mimics how professional ice block machines work. 

(All of the many, many ice experiments posts are located here in the Index of Ice Experiments.)



Today we'll talk about how to make clear ice with an aquarium pump and no cooler, and how this same method allows us to freeze objects in an ice block also without an insulated cooler.


While I've always favored the non-electricity Directional Freezing method, Alcademics reader fang2415 prefers to use an aquarium pump without (much) insulation. This takes up little less space in the freezer, and it seems like a much faster method than with insulation - as below, he says he gets a 4-liter ice block every day! 

In short, fang2415 places an aquarium pump at the top of an uninsulated container of water in the freezer, just barely insulating the top of the container with bubble wrap to help prevent it freezing over. He then found that this also works to freeze objects inside ice blocks. 

He describes the method:

The method is really simple: basically it's the same thing I now do to make most of my ice using an aquarium pump in a plain Tupperware-style plastic 5L container, but this time I threw a bottle inside the container and used tinfoil as a cover since the bottle was too tall for the lid to it.



I've been making all my ice this way recently, and every day I get a big beautiful 4-liter-or-so block of ice. The only real annoyance is cutting the pump out. 

I filled the container up to about .5 inch from the top and stuck my 150 L/H aquarium pump to the side just below the surface. Usually I aim the pump so that the outlet goes across the middle of the surface, but this time I kept it to one side so that the jet went around the side of the bottle's neck.

I've found that insulation barely matters with the pump method, although I usually cover the top with two layers of bubble wrap to reduce freezing at the top. Tying the bubble wrap with string works just fine; it just means that you need to knock the top ice-collar off at the end.

After chiseling the pump out (which is probably the most difficult part of the process), I had a bottle with the top conveniently exposed inside a large squarish block of clear ice. 


He then chisels out the aquarium pump and cuts or runs water over the outside edges to smooth out the block of ice and make the bottle label more legible. 

Thanks once again to dedicated ice nerd fang2415 for not only doing the experiments, but for taking pictures and sharing with the Alcademics audience!