Page 58 - Miracles Within the Molecule

HArun yahya

The Source of the Mıracle of Water: Hydrogen Bonds
At room tem per a ture, water is a famil iar liq uid. But this is most
inter est ing, because under nor mal con di tions, we would expect water to
be in a gas e ous state, like other small mol e cu les such as ammo nia and
meth ane. Water's liq uid nature stems from the small hydro gen atoms,
and the hydro gen bonds between water mol e cu les. As you know, cova -
lent bonds hold a water mol e cule togeth er, but one water mol e cule
attach es to anoth er via a hydro gen bond. As already stat ed, hydro gen
bonds are exceed ing ly weak, and the dura tion of a hydro gen bond is
approx i mate ly one hun dred bil lionth of a sec ond. However, the break -
ing of the bond does not destroy the assem bly of water mol e cu les,
because when one bond is bro ken, anoth er new one imme di ate ly forms.
As a result of this con stant renew al, water mol e cu les can not adhere to
one anoth er, but are vis cous. As a final result, instead of form ing a gas
in which mol e cu les move inde pend ent ly, water mol e cu les group
togeth er as a mov ing liq uid. This prop er ty of water, so dif fer ent from
that of sim i lar mol e cu les, is one of the basic neces si ties of life.
The weak hydro gen bonds between water mol e cu les also results in
the dif fer ent den si ties of liq uid water and ice. Almost all known sub -
stan ces are denser as a solid than in their liq uid form in. For exam ple,
under nor mal con di tions when you drop lumps of iron into mol ten iron,
the solid lumps will sink to the bot tom. Yet with water, this does not
hap pen because ice, water's solid state, is less dense than liq uid water.
When water freez es, every mol e cule grips tight ly onto its neigh bor
because of the hydro gen bonds, but the dis tance between these mol e cu -
les remains quite large. Therefore, gaps remain between the bonds, and
the struc ture of water in its solid form con tains more empty space than
its liq uid coun ter part, mak ing it less dense. 15 As a result, when you
drop ice cubes into a glass of water, the ice inev i ta bly rises to the sur -
face—as do ice bergs in the ocean.
This char ac ter is tic of water is of the great est impor tance for life.
Due to this effect of the hydro gen bonds, bod ies of water always start to
freeze from their sur face down. In win ter, ice forms on the upper lay ers

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