As familiar as water is to all of us, being one of the
most stable as well as most abundant compounds on earth, it is, nonetheless an
"odd" one. In many respects it is one of the " strangest" substances
known to science. Almost all its properties-boiling point, melting point, etc.- are "
anomalously" higher or lower than what one might expect based on its molecular mass
of 18 amu ( atomic mass units). Certainly, it is these unexpected properties of water that
make it a uniquely useful liquid and the basis for life. No other liquid can be
substituted for water in the role it plays. The following is a summary of some of its
unique characteristics.
1. To demonstrate how some properties of water(H2O) are
" anomalous,"
we compare it with other compounds in the series, H2S,
H2Se, H2Te, replacing Oxygen by Sulfur, Selenium and Tellurium; all in the same group and
chemically close. It is a general trend that within a given series of compounds, boiling
points and melting points increase with the increasing atomic weight of elements.
Accordingly, if we plot these properties of the four compounds against their atomic
weight, we expect them to follow this pattern. They all do EXCEPT water. For example,
being the lightest compound in the group, water is expected to have a boiling point close
to -75C (-105F). This is nowhere close to the actual boiling point of water, which is
+100C (+212F). Similarly, water is expected to have a freezing point at about -100C
(-145F). This is again much different than the actual freezing point of water. If water
did have the "expected" boiling and freezing points the result would be
dramatic; there would be No life, at least of the kind that we are familiar with.
2. The fact that water in the solid phase ( ice) is
less dense than the liquid phase ( water expands on freezing and ice floats on top) is
taken for granted by most of us and may on occasion cause annoyances as it results in
cracking water pipes. Yet this virtually unique property of water is essential for marine
life.
If ice were denser than water, it would sink and
accumulate at the bottom of ocean and lakes. Water in oceans and lakes would show radical
temperature changes with depth. The amount of ice would be greater each year as more and
more ice would be formed each Winter and less and less of it would melt each Summer. It
would not be long before all oceans would be totally frozen. As it is, the ice floats at
the top, thereby isolating water and marine life below, keeping the temperature from
dropping to the freezing point, and maintaining water as a liquid for marine life.
3. Water has a higher specific heat ( the amount of
energy it takes to raise its temperature) than all the compounds in the series, and higher
than almost all organic compounds. The higher values of both specific heat and thermal
conductivity allow water to be used as a storage of heat, and to buffer the temperature of
its surroundings. Without this property, we would have extreme of temperatures each day;
freezing cold as well as scorching heat within a short span of time, many times during a
single day, resulting in destruction of life. People who live in the desert experience
that, although to a very limited degree-very hot days and cold nights.
4. Water also has a very high surface temperature, a
phenomenon in which the surface acts as though it were a thin, invisible, elastic
membrane. It is because of this property that you can place a needle on the surface of
water if you do not break the surface. A consequence of this property is that it allows
biochemically important compounds to concentrate near the liquid surface and making some
biochemical reactions more rapid.
The high surface tension is responsible for the so
called capillary effect-rise of water in capillary tubes. It is this property that is
largely responsible for the transport of water, against gravity, within plants.
5. The dielectric constant ( measure of charge
distribution within a molecule) for water exceeds just about any other liquid, thus
allowing it to dissolve polar compounds, NaCl (table salt), into their constituent ions Na
and Cl. We tend to forget that water is, after all, the least expensive and the most
effective cleaning agent.
This also causes biochemically important compounds such
as enzymes and nucleic acids to exhibit what is known as the hydrophobic effect. By
aligning themselves toward or away from water molecules, enzymes are, in effect, formed
into their "active shape." It is established, biochemically, that it is the '
shape" of enzymes that enables them to catalyze biochemical reactions in the living
cell. The same enzyme, if laid out differently, would become inactive, thereby bringing
the life process to a halt.
Are these facts, are these very peculiar properties of
water simply an accident, or are they a result of a well thought out design?
54:49 Everything We created is
perfectly measured.
Once again, as in countless other examples, life and
evolution of life would not have been possible without the specific design of God. In this
case, it is properties of water molecules which depend almost exclusively on the special
bonding between Oxygen and Hydrogen. Any variation from the known water structure would
have resulted in vastly different properties for water with no possibility of life.
21:30 Do the unbelievers not realize
that the heavens and earth used to be one single entity which we then exploded into
existence?
24:45 And God created every living
creature from water...
11:17 He is the One who created the
heavens and the earth in six eons- and His dominion rests on water.
All praise belongs to God
- Hossein Kowsari
