Water molecules are
very polar:
* The oxygen atom
attracts its shared
electrons strongly, so
the oxygen atom has a
slightly negative
charge.
* The hydrogen has a
slightly positive
charge.
* This makes them “stick”
to each other with a
strong attraction called
a hydrogen bond
.
Name: _________________
O
H
H
hydrogen
bond
O
H
Water has a high specific heat:
* High specific heat means it
takes a LOT
of energy to
change a body of water’s
temperature
.
* Aquatic life can live without
rapid/deadly changes in
temperature
.
H
O
H
H
Pr perties f Water
Ice is less dense than water:
* Ice forms at the top of water because
of the cold air. Aquatic organisms that live
underneath the ice in the water are
insulated
from extreme cold by the ice.
* This also allows for some animals to live
on top of the ice!
Capillary Action:
* Water moves up thin
tubes
within plants!
* Water is drawn up the tube,
against gravity
, by the
forces of cohesion
and
adhesion
.
adhesion cohesion
water
© Bethany Lau
Water has a strong surface tension:
* Molecules at the surface hold more tightly
to each other than molecules further under
the surface.
* Some life depends on being able to float
on top of the surface.
* This is also why water can bead up into
droplets on glass surfaces
.
H
H
O
Water is a terrific solvent:
* Many ions and polar molecules
necessary for life can dissolve in water.
* Water is great for carrying these ions
and molecules within cells or blood vessels
between different body tissues.
H
O
O
H
H
H
H
H
O
H
H
O
O
H
H
H
O
H
H
H
O
O
O
O
H
H
H
H
H
H
O
H
O
H
H
H
H
H
H
H
O
O
H
O
H
O
O
O
H
H
H
H
H
H
-
H
H
H
+
O
O
O
O
H
H
O
H
O
H
H
H
-
H
+
O
H
H
H
H
H
H
O
H
O
H
H
O
H
Imp rtant f r Life
Water has a relatively high boiling point and heat of
vaporization for a small hydride molecule:
* It takes a lot of heat energy for water molecules to
leave their liquid form , held together by
hydrogen bonds.
* Because water does not boil at a lower temperature,
most water on the planet is found in the form of liquid ,
which is essential for life!
* Surface water molecules can evaporate when
individually they gain enough energy
to break free
from the hydrogen bonds of the molecules around them.
H
H
H
O
O
H
H
O
H
H
O
H
O
H
H
O
O
H
H
H
O
O
H
H
H
O
H
H
H
H
O
H
O
H
H
H
O
H
H
H
H
H
enough heat
energy
surface
molecule
O
H
H
O
H
Is there water on other
planets?
* Many moons in our solar
system have evidence of ice
and perhaps liquid water is
underneath.
* Scientists believe
liquid water
is a
requirement for life to exist,
which is why we keep looking
for it!
* Most planets are too hot
or too cold
for liquid
water to exist.
© Bethany Lau
Water molecules are
very polar:
* The oxygen atom
attracts its shared
electrons strongly, so
the oxygen atom has a
slightly
charge.
* The hydrogen has a
slightly
charge.
* This makes them “stick”
to each other with a
strong attraction called
a
.
Name: _________________
O
H
H
hydrogen
bond
O
H
Water has a high specific heat:
* High specific heat means it
takes
of energy to
change a body of water’s
.
* Aquatic life can live without
rapid/deadly changes in
.
H
O
H
H
Pr perties f Water
Ice is less dense than water:
* Ice forms at the
because
of the cold air. Aquatic organisms that live
underneath the ice in the water are
from extreme cold by the ice.
* This also allows for some animals to live
on top of the ice!
Capillary Action:
* Water moves up
tubes
within plants!
* Water is drawn up the tube,
against
, by the
forces of
and
.
adhesion cohesion
water
© Bethany Lau
Water has a strong surface tension:
* Molecules at the surface hold
to each other than molecules further under
the surface.
* Some life depends on being able to float
on top of the surface.
* This is also why water can bead up into
droplets on glass surfaces .
H
H
O
Water is a terrific solvent:
* Many ions and polar molecules
necessary for life
in water.
* Water is great for carrying these ions
and molecules within
or
between different body tissues.
H
O
O
H
H
H
H
H
O
H
H
O
O
H
H
H
O
H
H
H
O
O
O
O
H
H
H
H
H
H
O
H
O
H
H
H
H
H
H
H
O
O
H
O
H
O
O
O
H
H
H
H
H
H
-
H
H
H
+
O
O
O
O
H
H
O
H
O
H
H
H
-
H
+
O
H
H
H
H
H
H
O
H
O
H
H
O
H
Imp rtant f r Life
Water has a relatively high boiling point and heat of
vaporization for a small hydride molecule:
* It takes a lot of heat energy for water molecules to
leave their
, held together by
.
* Because water does not boil at a lower temperature,
most water on the planet is found in the form of
,
which is essential for life!
* Surface water molecules can evaporate when
individually they gain enough
to break free
from the
of the molecules around them.
H
H
H
O
O
H
H
O
H
H
O
H
O
H
H
O
O
H
H
H
O
O
H
H
H
O
H
H
H
H
O
H
O
H
H
H
O
H
H
H
H
H
enough heat
energy
surface
molecule
O
H
H
O
H
Is there water on other
planets?
* Many
in our solar
system have evidence of ice
and perhaps liquid water is
underneath.
* Scientists believe
is a
requirement for life to exist,
which is why we keep looking
for it!
* Most planets are
or
for liquid
water to exist.
© Bethany Lau