When Water Freezes.

New Zealand Tablet, Volume XXX, Issue 14, 3 April 1902, Page 15

When Water Freezes.

A RCIENtii ie writer points out a number of the most common and obvious facts of nature, like the saltness of the sea, and shows how they prove the wisdom and beneficence of the Creator. Of the fact that waUr is heaviest when its temperature is seven degrees above the fiee/Jng point he Pays :—: — If pome such difference did not exist, this would be a strange world. Generally, as a substances is cooled, it grows denser — that is, heavier. Nearly all substances, such as iron, lead, the varous salts, etc.. grow denser and denser as they become colder and colder. But water has the curious property of growing denser down to 3!) degrees of temperature, and then beginning to expand. At 3 ( .) degrees it is heaviest, and when it has become ice it is considerably lighter. The consequence is, that when cold weather comes on, the surface water of a lake grows cold, dense, heavy, and sinks to the bottom, the warmer water rising to the top. But when the temperature is lowered below :?y degrees the coldest water remains on top. as it is then lighter than the warmer water. This layer soon becomes ice, and the ice, being the lightest part of the lake, floats. After the first thin layer i& frozen any further manufacture of ice must be effected by conduction of cold through the ice already formed. And as thia is a slow process the layer thickens very gradually, Now think what would happen if water, like iron, continued to grow denser no matter how low its temperature sank. The ice, being the coldest part, would sink to the bottom. More ice would quickly be made on the surface and sink, too. After a single night's Bevere fro^t there would be several Teet of ice at the bottom. At the end of some few weeks deep lakes would have become solid masses of ice. This would mean death to all the living creatures they contained. And when the summer came, only a fathom or two of the lakes would unfreeze for the warm water would float on top and the sun's rays couldn't penetrate very far down.