Properties of Water
{
What-er weird molecule
Water is all around
us…but have you ever
stopped to think about it?
Properties of Water
1.
2.
3.
Specific Heat
Polarity
Density
As Matt Smith would say…
 (very very strange)

Specific Heat
Specific Heat - the amount of heat required to
raise the temperature of a set, or standard,
amount of matter by one degree Celsius
Ex. At 35 °C Specific Heat of:
Water 4.185 KJ/KgK
Peanut Oil 2.095 KJ/KgK
* KJ/KgK = Kilojoule per Kilogram x °Kelvin
Specific Heat
What in the world does that mean!?

If the water is 60 °C…

And you have 1 kg of water…

You would need 4.185 KJ of energy to increase
the temperature by 1 measly degree Celsius!

A 40 Watt light bulb uses 3,456 KJ if left of for
24 hours
Polarity
Polarity - the state of having two opposite or
contradictory sides
Why would water be considered polar?
Hint:
Bigger Hint
Polarity
Polarity causes water to do some REALLY weird
things…
Maybe not that weird…
Or that weird…
…But it does allow it to:
1.
flow against gravity
2.
Let things walk on its liquid surface
a)
3.
Jesus Lizard
Change its density in a way that no other substance
really does.
Polarity
Adhesion vs. Cohesion
Cohesion – The act of two pieces of the same
substance sticking together

when H2O “sticks” together with more H2O
Adhesion – The act of two different substances
sticking together

when water and something else “stick” together
Polarity
Cohesion

Responsible for SURFACE TENSION
What is Surface Tension? (No really, ask me!)
http://water.usgs.gov/edu/surface-tension.html

Surface Tension – (You tell me!)

Surface Tension – A barrier on the uppermost
layer of water that is difficult to penetrate until
broken. It is created by a strong cohesive force
between the top layer of water molecules.


Polarity
Just how strong is the
force of cohesion in
surface tension?
Polarity
Penny Lab!!
1.
With the person next to you (let Mr. H pair you).
2.
Person 1 fill a beaker with water and obtain a penny & eye
dropper.
3.
While Person 1 is collecting materials, clear your desk
space and make a hypothesis of how many water drops
will fit on the surface of a penny.
4.
Fill your eye dropper with water and gently drip drops of
water onto the penny (BE CARFUL TO NOT BUMP THE
TABLES!)
5.
Count how many drops fit on top of the penny.
6.
Clean your lab station and answer this question:
•
In your own words, how strong is the force of cohesion in
water tension?
Polarity
Adhesion creates capillary action
Go ahead, ask me what it is!
Pretty please!
With sugar on top?
And rainbow sprinkles!?
I’m soooooo glad you asked!
http://water.usgs.gov/edu/capillaryaction.html
Capillary Action – the movement of water within the spaces of a
porous material due to the forces of adhesion, cohesion, and
surface tension.
Examples:
1.
Water climbing your graduated cylinder…
Polarity
Water is the UNIVERSAL SOLVENT
Solvent – A substance that does the dissolving
Solute – A substance that gets dissolved
It’s because of an uneven distribution of electrons!
Polarity
Water is the UNIVERSAL SOLVENT
Soil is charged too! That’s why soil gets carried away when it
rains!
This can create rivers!!
(change powerpoint Mr. H!)
Polarity
Water density graphing activity!