Download File - Biology Fall Semester

Objectives


Discuss the properties of water
Analyze the role of water properties in
biology
1
Vocabulary
Polar
 Cohesion
 Adhesion
 Specific heat capacity

Surface tension
 Capillary action
 Solvent
 Solute

2
Why
Does
a
belly
flop
hurt?
The Unique
Properties of Water
3
Water is a polar molecule.
Water has a
positive
pole and a
negative
pole.
4
The (+) pole
of one water
molecule is
attracted to
the (-) side of
another water
molecule.
5
Cohesion

So a “net” of water molecules forms.
When water sticks to itself it is called
cohesion.
6
Adhesion

When water sticks to something else it is
called adhesion.
7
Capillary Action
Water can defy gravity
when flowing
through
small tubes (in a
closed environment).
How does blood
“feed” every cell,
even at the extreme
tips of your body?
8
Surface Tension

Surface tension is the top layer of water
molecules cohering to each other
9
Specific Heat
Specific heat refers to
the ability of a
substance to heat
up 1 gram 1oC
For water, which has
a high specific heat,
this means it takes
a large amount of
energy to heat up
water.
But once it is heated,
water holds heat.
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Specific Heat
So, your body is
a like a car’s
radiator.
When blood
flows heat is
evenly
distributed
from the inside
out.
11
Density
Water floats when frozen.
Remember: When freezing, more bonds are created between
the molecules. Normally this means the molecules take
up less space (volume). But for water, as it freezes, the
bonds increase spacing between themselves creating a
larger volume space but the mass remains steady.
12
Universal Solvent
Universal Solvent:
Water dissolves
most polar
substances.
 Why is your blood
mostly made of
water?

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Let’s Review.
List the properties of water.
14
Review
1.
2.
3.
4.
5.
6.
7.
8.
Polar
Cohesion
Adhesion
Specific heat capacity
Density(Floats when frozen)
Surface tension
Capillary action
Universal solvent
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