The physical properties of ice

Ice has a singular property, which is apparently banal, but which has important repercussions on the life of the entire planet. While most substances decrease in volume when changing from the liquid state to the solid state, the property of water is that it is less dense in the solid state than in the liquid state: in fact, maximum density of water is reached at a temperature of 4°C.
This implies that ice is lighter than an equivalent quantity of liquid water, therefore ice floats on water : this can be seen when sipping a drink in a glass full of ice cubes. However, in nature, the same phenomenon can be seen in the icebergs and in the formation of sea and lake ice.
If ice did not have this property, ice formed on the surface of a sheet of water (a lake or a sea) would sink, accumulating on the bottom. This would finally form thick deposits of ice on the bottom of seas and lakes, which would soon be transformed into large masses of ice, and the summer heat would only produce a minor layer of liquid water near the surface. The consequences of this property on the life of our planet are therefore very easy to imagine.
As a result of this property, when water freezes its volume increases. This is easy to test, when we put a bottle of water in the freezer, the pressure of the ice can break the bottle – if the bottle is full, the ice does not have space to expand and the container cannot deform, as in the case of a glass bottle. In nature, this process is very important : the pressure of water freezing inside small cracks in a rock can be so great that the rock breaks into small fragments. This process, called cryoclastic weathering (from Greek cryo, kryos : cold and clast, klastos: broken), (freeze-thaw weathering or frost shattering) is responsible for mechanical weathering of rocks in the high mountains, and produces large stretches of sharp debris, which are a characteristic feature in mountain landscapes above the limit of arboreous vegetation (that mountain climbers and excursionists call “screes” – those who are familiar with the mountains know how tiring it is to walk on this large gravel!).

Special reports

  • 10 December 2019

    In the fridge of the world

    Antarctica is a continent with a very particular charm...

    26 December 2019

    Life in Antarctica

    How is it possible to live and work in Antarctica...

    15 April 2014

    How rich are we …. in blue gold?

    Water footprint, water availability and use on a planetary scale...

  • 26 February 2014

    How much water is on your plate?

    Water footprint and water consumption...

    8 July 2022

    Who’s coming to dinner

    A shark in my hamburger Summer is finally here! As usual, we have waited for it all year long and…

    7 October 2021

    Water grabbing

    “Clear, sweet fresh water,” wrote Petrarch, by many considered a precursor of Italian literature. Before him, St. Francis dedicated two…

  • 17 May 2021

    Lost ice

    According to a study conducted by a French and Swiss research team recently published in the leading journal Nature, continental…

    15 April 2021

    Oceans of plastic

    The invisible invasion of microplastics...

    26 December 2019

    Life in Antarctica

    How is it possible to live and work in Antarctica...

From the Multimedia section

  • water

    Ice and currents

    Look

    water

    Captured water

    Look

    water

    Ice tales

    Listen
  • water

    Careser Glacier mass balance

    Look

    water

    Ice shapes

    Look

    water

    Scheme of glacial cave systems

    Look
  • water

    How ice forms

    Listen

    water

    Ice flow-lines within a glacier

    Look

    water

    Retreat of the Aletsch glacier

    Look

Facts