Pure water contains no impurities and freezes at 0°C. However, seawater – on average – contains 3.5 per cent of dissolved salts, which lowers the freezing point; this phenomenon is called freezing point depression. Freezing point depression is a colligative property of matter, which means it depends on the number of molecules present, not on the specific type of molecule or their mass (i.e. the dissolved substance doesn't have to be salt, but any soluble substance, it's the amount of dissolved molecules that is important). In terms ...

Amazing NASA images of the British Isles blanketed in snow Image courtesy of NASA The Moderate-Resolution Imaging Spectroradiometer (or MODIS) on board NASA’s Terra satellite captured this incredibly chilling image of Great Britain on 7 January as most areas experienced freezing temperatures of -10C on the coldest night of the winter so far. Isolated areas were even subjected to lows of -22C in the Scottish Highlands. Snowfall followed by freezing temperatures left areas dangerously icy, resulting in widespread chaos ...