Water has unique properties that allow it to perform important functions. It is made of molecules consisting of one oxygen atom and two hydrogen atoms. Its density is lower than ice, allowing ice to float. Water is a powerful solvent that can dissolve many substances like grease, oil, oxygen, and carbon dioxide. It has a high specific heat capacity meaning it does not get hot or cold easily, helping to moderate Earth's climate. Water's cohesion and adhesion properties result from the attraction of water molecules to each other and other substances. This allows water to form drops, climb tubes through capillary action, and be absorbed by plants, which all rely on these properties to survive.

1. WATER PROPERTIES

2. Water has unique properties
• It is made of molecules.
• Each molecule is made up of one atom of
oxygen and two atoms of hydrogen.

3. The main properties
• Density and dilation. The density of the ice is
lower than the density of the water. Ice floats
on water.
• A powerful solvent. It can dissolve many
solvents.
– Can water dissolve grease, oil?
– Can water dissolve gases such as oxygen and
carbon dioxide?

4. • It has a high specific heat. Water does not get
hot or cold easily.
– Water is an ideal substance to absorb and
accumulate heat.
– Water moderates the Earth´s climate.
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•
•
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Cohesion
Adhesion
Surface tension
Capillarity

5. Adhesion and cohesion
• Cohesion: Water is attracted
to water.
• The water drop is composed
of water molecules that like
to stick together
Adhesion: Water is attracted
to other substances

6. • Water drops on pine needles, showing the
effects of gravity, adhesion, and cohesion on
water.
Cohesion is seen in the actual water drop—the water
molecules stick to each other, forming a drop.
Property of gravity, which is causing the water drops to roll
along the pine needle.
Property of adhesion is holding them, at least for now, to the
pine needle.

7. • Cohesion makes a water drop a drop
– The drop seems to have a "skin" holding it
– It turns out that this surface tension is the result
of the tendency of water molecules to attract one
another.

9. Capillarity action
• Capillary action seen as water climbs to
different levels in glass tubes of different
diameters.
• The movement of water within the
spaces of a porous material due to the
forces of adhesion, cohesion, and
surface tension.

10. • Plants and trees
couldn't survive
without capillary
action (adhesion and
cohesion forces)

11. Surface tension
• Floating paper clip made of steel The high
surface tension helps the paper clip - with
much higher density - float on the water.
• the cohesive forces between liquid molecules
are responsible for the phenomenon known
as surface tension.

13. • Walking on water: Small insects
such as the water strider
(pondskater) can walk on water
because their weight is not
enough to penetrate the surface.

14. • Don't touch the tent!: Common tent materials
are somewhat rainproof
• But if you touch the tent material with your
finger, you break the surface tension and the
rain will drip through.