Melting, freezing and the solid state of water are much more complicated than most of us think.įor starters, did you know there are at least eleven different types of ice? The freezer in your kitchen turns water into a substance known to science as 'ice Ih'. It's tempting to give pressure all the credit for this, but dig a little deeper and this simple explanation runs into trouble. The presence of the wire melts the ice below it and the water above refreezes above. It is water's curious ability to weld itself together and it is so notoriously tricky to explain that it has remained a source of spirited scientific debate for more than 150 years. The phenomenon you are witnessing is called 'regelation'. Once the wire has passed right through, you can pick the ice cube up and inspect the frozen 'tracks' where the wire has been. Over the course of 10 to 15 minutes, the wire will pass right through the ice cube which 'magically' heals itself by refreezing above the wire. The full weight of the bottles pulling down on the wire exerts a huge amount of pressure on the ice cube. Now suspend the bottles over the ice cube. Lay a brick or another heavy object on the other end of the ruler.Ĭut a piece of styrofoam to the size of an ice cubeand lay it on the end of the ruler and place an ice cube on top. Lay a ruler on a table so one end protrudes over the edge of the table. Tie two used two-litre soft drink bottles with water (you can use two unopened bottles too) to the ends of your wire. If you are using garden wire, strip the plastic off with a sharp knife (very young scientists will need an adult helper to do this). Alternatively, copper wire, an old guitar string or even thin fishing line will do (fishing line will take longer). Ice can melt under pressure and it will refreeze when the pressure is reduced, but while that is all easy enough to say, the science behind it is tricky. Video: Slice ice experiment (Science Online Video)Ĭan't see the video? Download an mp4 version of this video.
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