How to Make Ice Spikes in your Freezer

Making and Understanding Ice Spikes

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Ice spikes are tubes or spikes of ice that shoot up or off at an angle from a container of frozen water, such as a bird bath or bucket in the winter. The spikes resemble an inverted icicle. Ice spikes form rarely in nature, but you can make them in your own freezer quite simply and reliably. Here's what you do.

Ice Spike Materials

  • distilled water
  • ice cube tray
  • frost-free freezer (ordinary home freezer)

It's important to use distilled or reverse osmosis purified water. Ordinary tap water or mineral water contain dissolved substances that may prevent the water from forming spikes or reduce the number of spikes that are formed.

You can substitute a bowl or cup for the ice cube tray. Plastic ice cube trays are nice because they contain several small compartments, meaning you have a quick freeze time and several chances for spikes.

Make Ice Spikes

It's easy! Simply pour the distilled water into the ice cube tray, set the tray in your freezer, and wait. You can expect about half of the ice cubes to contain ice spikes. An ordinary ice cube tray freezes in about 1-1/2 to 2 hours. The spikes degrade and soften over time since most home freezers are frost-free and will blow warmer air over the spikes.

How It Works

Pure water supercools, which means it remains liquid past the ordinary freezing point. When it starts to freeze at this lower temperature, it solidifies very rapidly. The freezing process starts at the edges of the container because the nicks, scratches, and imperfections allow for nucleation of the ice crystals. Freezing continues until there is only a hole near the middle of the container, which contains liquid water. Ice is less dense than liquid water, so some of the crystals float to the top and are pushed out, forming a spike. The spike grows until the water is frozen.

There are two reasons why ordinary tap water or mineral water are less likely to form ice spikes. The first reason is that this water tends to freeze at its regular freezing point. This is a much slower process than freezing from the supercooled state, so solidification is more likely to be homogeneous or occur throughout the ice cube all at once. If there isn't a hole in the ice, the ice spike can't grow. The other reason is that contaminants or impurities in the water become concentrated in the liquid as the water freezes. Researchers believe solids become concentrated at the growing tip of an ice spike and inhibit further growth.

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