~ / okay ay and to do econ it should be the good for goid day some more words iam done

Almost there i like i so much

- The molecule of water is polar (dipolar)
-oxygen is more electronegative than hydrogen
- clovalent bond between o and H
- electron pairs push down (repell) covalent bonds down

- In absolute zero molecules don't make at all 0° K (not only water but all)
- melting point - solid to liquid,
- boiling point - liquid to gas,
- water can attract or repell water mollecules mealier
- water being polar can make hydrogen bonds
- one water molecule can make four hydrogen bond (intermollecter forces of ar attraction)
-hydrogen bonds are less strong than chemical bonds
- in freezing point every water molecule has 4 hydrogen bonds (form latice)
- in gas state there are almost no hydrogen bonds
- hydrogen bonds exist in solid and liquid hz0 state
- ice has lower density than water so it floats
- ice isolates lower layers of water from cold so that aquatic organisms can live
 A 1.1 – Water

“What physical and chemical properties of water make it essential for life?”
“What are the challenges and opportunities of water as a habitat?”
 Students should appreciate that the first cells originated in water and that
water remains the medium in which most processes of life occur. Students
A1.1.1 Water as the medium for life should understand that polarity of covalent bonding within water molecules is
due to unequal sharing of electrons and that hydrogen bonding due to this
polarity occurs between water molecules.

Hydrogen bonds as a consequence of the Students should be able to represent two or more water molecules and
hydrogen bonds between them with the notation shown below to indicate
A1.1.2 polar covalent bonds within water polarity.
molecules
Cohesion of water molecules due to Include transport of water under tension in xylem and the use of water surfaces
as habitats due to the effect known as surface tension.
A1.1.3 hydrogen bonding and consequences for
organisms
Adhesion of water to materials that are Include capillary action in soil and in plant cell walls.
A1.1.4
polar or charged and impacts for organisms
Solvent properties of water linked to its role Emphasize that a wide variety of hydrophilic molecules dissolve in water and
that most enzymes catalyse reactions in aqueous solution. Students should also
A1.1.5 as a medium for metabolism and for understand that the functions of some molecules in cells depend on them being
transport in hydrophobic and insoluble.

Include buoyancy, viscosity, thermal conductivity and specific heat. Contrast

Physical properties of water and the the physical properties of water with those of air and illustrate the
A1.1.6 consequences for animals in aquatic consequences using examples of animals that live in water and in air or on
land, such as the black-throated loon (Gavia arctica) and the ringed seal (Pusa
habitats hispida).

The abundance of water over billions of years of Earth’s history has allowed
A1.1.7 Extraplanetary origin of water on Earth and life to evolve. Limit hypotheses for the origin of water on Earth to asteroids
AHL reasons for its retention and reasons for retention to gravity and temperatures low enough to condense
water.

Relationship between the search for

Include the idea of the “Goldilocks zone”.
A1.1.8 extraterrestrial life and the presence of
AHL
Water as the medium of life

Life has originated in the

water, with first cells
enclosing a small volume
of it in a membrane, where
solutes dissolved and
chemical reactions
h
t occurred.
t
p
s
:
/
/
w
w
w
.
o
e
c
d
. The interaction of molecules
o
r
g
in water is the basis of all life.
/
w
a
t
Water as the medium of life Over 70% of Earth’s
surface is water, with
most of water found
in oceans. Water
forms a large
proportion of living h
t
t
organisms. p
s
:
/
/
r
e
a
s
o
n
s
.
o
r
g
/
e
x
p
l
o
r
e
/
b
l
o
g
s
Water as the medium of life Water is found between cells
of multicellular organism as
What makes water so interstitial fluid.

useful for cells?

Water is crucial
for organism
because it makes
up the fluid
(cytoplasm) in all
cells and within
organelles.

Because water is a good solvent it

allows the transport of substances
into and out of cells, or in the
The cytoplasm is blood in form of plasma.
where metabolic
reactions occur -
enzymes rely on the
collisions between
molecules to
catalyze reactions.
 .

Water as the medium of life c

o
m
/
Most of a cell and its organelles are made up from water, forming the cytoplasm. s
c
i

h
The cytoplasm and organelles t
a
b
t
t
are fluid filled with 85% of that l
e
p
s fluid being water. Chemical and /
t
:
/
/
metabolic reactions work best o
p
w
w
in an aqueous environment. i
c
w p
. a
a
g
s
e
t
/
r
o
w
n h
o a
m t
y Early cells evolved membranes to separate their insides -
.
c
(cytoplasm) from the ocean water. Cell membranes i
s
o (phospholipid bilayers) naturally form in aquaeous medium. -
m
a
/
-
s
c
c
i
e
e l
n l
c -
e 1
/ 4
f 0
i 2
r 3
s
0
Hydrogen bonds in water due to polar covalent bonds
h
t
t
p H
: (+ O (-
/
/ ) )
w
w
w
.
e
u
c
l H
i
d (+
l
i
)
b
r
a
r
y Water molecules have polar covalent bonds – this is due to the
.
o unequal attraction of electrons towards the nuclei of the
r
g involved atoms. The oxygen atom has a larger nucleus with 8
/
i protons than hydrogen with only 1 proton. Because of this, the
m
a
shared electrons from the covalent bond and unshared
g
e
electrons are pulled closer to the nucleus of the oxygen atom.
s
http://www.ces.fau.edu/nasa/images/module_3/WaterMolecule.gif
Hydrogen bonds in water due to polar covalent bonds
The unequal sharing of electrons in the covalent bond
between oxygen and hydrogen causes a partial positive
charge over H: + and a partial negative charge over O:
-
Draw the structure of a water
molecule, clearly showing
electrons and covalent bonds:
Hydrogen bonds in water due to polar covalent bonds
Hydrogen bonds are weak forces of attractions, which are
formed between the opposite polarities (caused by polar
covalent bonds) of adjacent water molecules. The partially
positive ( +)end of one water molecule is attracted to the
partially negative ( -) end of another water molecule.

Draw 3-4 water

molecules & their
hydrogen bonds:
The biological properties of water
Cohesion, adhesion and solvent properties of water are all explainable through
the polarity of water molecules and hydrogen bonds between molecules.

https://youtu.be/0eNSnj4ZfZ8
Cohesion of water molecules due to hydrogen bonding
…. and consequences for organisms
Cohesive forces of water molecules are
caused by the hydrogen bonds between
them. A single hydrogen bond is a
weak intermolecular force of attraction,
but the summative force of all
hydrogen bonds is very strong.

Each water molecule hydrogen

bonds with four others in a
tetrahedral arrangement, making
water cohesively “stick together”.
http://images.fineartamerica.com/images-medium-large/-spakling-water-droplet-tracie-kaska.jpg
Cohesion of water molecules due to hydrogen bonding
…. and consequences for organisms

Water can form

droplets due to surface
tension, which is a
consequence of
cohesive forces due to
hydrogen bonding
between water
molecules.
Cohesion of water molecules due to hydrogen bonding
…. and consequences for organisms

h
t
t
p
s
:
/
/
s
a
y
l
o

Surface tension causes droplet formation in

r
d
o

water. It is established because the molecules t

o
r

on the outside of a water body form hydrogen g

.

bonds with the water molecules below them.

g
i
t
h

These molecules have no neighboring

u
b
.

molecules above them to bond with, so they i

o
/

have stronger attractive forces upon their t

e

nearest neighbours on and below the surface

x
t
_

of water making them contract inwards. g

e
n
Cohesion of water molecules due to hydrogen bonding
…. and consequences for organisms
Surface tension makes water a
habitat for insects to live on or
underneath. The surface tension is
Mosquito
strong enough to support the mass of larvae using
insects (which is not great enough to the bottom
surface of
break the hydrogen bonds water as a
habitat
responsible for surface tension). https://commons.wikimedia.org/wiki/File:Close-up_of_Culex_mosquito_larvae_in_water.jpg
Pondskaters or
waterstriders
walk on water
using their 6
legs

Some spiders hunt

on prey on the
surface of water
https://upload.wikimedia.org/wikipedia/commons/1/1a/WaterstriderEnWiki.jpg https://travelspirit333.files.wordpress.com/2011/10/p1011277.jpg
https://passtheknowledge.wordpress.com/tag/how-do-spiders-walk-on-water/
Cohesion of water molecules due to hydrogen bonding
…. and consequences for organisms Cohesion allows the transport of
water under tension in plants.
Water molecules stick together
via hydrogen bonds, and the
pulling forces caused by the
evaporation of water from the
leaves (transpiration) makes
water move upwards against
gravity as an intact water column.
Adhesion of water to polar or charged surfaces
Adhesion is the attraction between the polar ends of water molecules and
polar surfaces. Water molecules form hydrogen bonds between each other
& polar materials such as membranes, containers, spiderwebs, cellulose
fibers in xylem vessel & other hydrophilic materials.
h
t
t
p
s
:
/
/
u
p
l
o
a
d
.
w
i
k
i
m
e
d
i
a
.
o
r
g
/
 h

Adhesion and its impacts for organism t

t
p

The formation of a meniscus :

/

of aqueous solutions in test /

i
m
tubes is the result of a
g

adhesive forces between e

.

polar water molecules and

s
l
i
the polar surface of the d
e

glass tube. Nonpolar liquids s

h

(e.g. mercury) do not form a

a
r
e

meniscus. c
d
n
.
c
o
m
/
s
t
a
t
e
s
o
f
m
a
t
t
e

Water droplets form beads on polar surfaces of pine r

-

needles or plant leaves, sticking to them without falling off.

1
2
http://scientificgamer.com/blog/wp-content/uploads/2012/11/drops.jpg
Adhesion and its impacts for organism
Adhesion and
cohesion are
different
concepts. Can
you explain
how they are
different?
 w

Adhesion and its impacts for organism w

.
l
i
Because water is attracted to n
k
polar or charged materials, it e
d

can also be drawn through i

n

narrow tubes such as xylem .

c

vessel in the stems of trees. o

m
/
p
u
l
This effect is called capillary action s
e
and also shown in porous solids (soil, /
r

paper, cellulose fibers) or narrow glass o

l

columns, which act as capillary tubes. e

-
c
a
p
i
l
l

Capillary action helps water be drawn into a plant from an

a
r
y
underground source in the soil, as soil contains many thin -
p
channels acting as capillary tubes. Adhesion between the r
e
water molecules and the soil particles cause water to s
s

move above the water table and into the roots of a plant. u
r
e
Adhesion and its impacts for organism
Resurrection plants like the “rose of jericho” (Selaginella lepidophylla) is able
to dehydrate and completely rehydrate again. Rehydration involves water being
drawn rapidly through the desiccated cell walls, by capillary action.
Adhesion and its impacts for organism
Capillary action due to adhesion allows water to be drawn up in plants because
the cell walls are made of polar/hydrophilic cellulose fiber acting like wicks,
causing water to adhere to the cell walls.
Due to the capillary action,
plant cells that are exposed
to air (cells in the leaf) are
kept continously moist
drawing in water from
nearby xylem vessels as
long as there is a source of
water available.

If a xylem vessel becomes air-filled,

adhesion between water and the wall
of the vessel can help the vessel to
refill with water. This is required by
plants in spring after the winter
months, where xylem vessels become
air filled to prevent frost damage.
Like solves alike
Solvent properties of water
Substances such as salts (NaCl, sodium chloride) with a positive or
negative charge due to their ionic composition are attracted to the
h

polar water molecules and therefore dissolve in water easily. t

t
p
s
:
/
/
t
h
e
o
r
y
.
l
a
b
s
t
e
r
.
c
o
m
/
s
o
l
v
e
n
t
-
w
Solvent properties of water
Watch these two videos and explain why polar substances like salt (NaCl,
Sodium chloride) dissolves easily in water.

https://1drv.ms/v/s!Au8ZKE_EDcrQhK5uRZYcPP4vl-MN6g?e=cFDSFW

https://1drv.ms/v/s!Au8ZKE_EDcrQhK9Kws7dlWuZnpkrKA?
Solvent properties of water
Because water is a good solvent, it is a medium for metabolic and enzyme
catalyzed reactions. Enzymes require some water to maintain shape and
stability, enabling them to function. Hydrogen bonds form between enzyme
binding sites and their substrates allowing reactions to take place.
All reactants need Solutes such as amino
to be dissolved in acids, salts, sugar and ions
the cytoplasm of a needed for cell processes
cell to carry out are dissolved in the plasma
chemical and of blood, which is made up
enzymatic mostly by water.
reactions.

http://www.newhealthadvisor.com/images/1HT00352/low%20red%20blood%20cell%20count.jpeg
 /

Solvent properties of water /

2
.
b
91% of the plasma of blood is composed of water. The solubility of p
.

substances in blood is therefore important for an effective transport b

l
o
around the circulatory system. g
s
p
o
t
.
c
o
m
/
-
6
8
k
z
A
y
B
V
u
v
A
/
U
w
Q
l
E
W
i
v
v
e
I
/
Solvent properties of water Hydrophili
water lovin
h
t
c charged molecules
Polar (partially g with
t
p
a polar covalent bond) or charged
:
/ molecules are said to be hydrophilic and
/
w
w
are therefore soluble – they dissolve
w
.
well in polar liquids like water.
m
i
d
d
l
Examples of
Cellulose, glucose, amino acids with polar
hydrophilic
e
s
c side chains, ionic compounds (e.g. salt), the
h
o
o
l
substances:
phosphate heads of phospholipids…
c
h
e
m
i
s
t
r
y Polypeptides and their respective variable
.
c side groups orientate themselves towards
o
m
or away from the water, depending on
/
i
their associated polarity or charge.
Solvent properties of water
Substances that are insoluble in water are
Hydrophobi
h

molecules that don’t have a negative or t

t

positive charge or are non-polar. They are p

c water :
hating
hydrophobic and repel water molecules.
/
/
f
Hydrophobic molecules dissolve well in non- .
t
polar solvents (e.g. acetone, chloroform). q
n
.

Examples of c
o
m

hydrophobic
/
Lipids (fats and oils), fatty acids, y
/
cholesterol, waxes, nitrogen c

substances:
gas…
h
e
m
i
s
t
r
y
/
1
/
L
Substances such as the phospholipid
/
9
bilayer of membranes have /
R
hydrophobic (water hating) and /
2
http://test.classconnection.s3.amazonaws.com/823/flashcards/391823/jpg/phospholipid-bylayer.jpg hydrophilic (water loving) features.
/
Solvent properties of water
What are the features of
glucose and how does this
affect its issolubility
Glucose in water
polar and hydrophilic,
h
and when placed in water forms
t
t hydrogen bonds between hydroxyl
p
:
/
groups (-OH groups) of the polar
/
4
glucose molecule and the polar sides
of the water molecules. This is
.
b
p
.
b
essential for its transport in blood.
l
o
g
s
p
o
t
.
c
o
m
/
-
7
1
T
u
X
J http://www.metallacycle.com/chemistry/aqueous-solutions/solvation-models/img/glucose-solvation.png
Solvent properties of water
Amino
There are 20
common amino
acids
acid, each is
characterized by a
different side
chain. The side
chain (R-group)
can be charged,
polar or nonpolar Side groups
(hydrophilic and
hydrophobic, Depending on the properties of the side group
respectively). of the respective amino acid, it will dissolve
better or worse in water. All of them are soluble
enough to be carried in blood plasma.
Solvent properties of water Oxygen, Nitrogen,
MostCarbondioxide
gases are entirely nonpolar and
hydrophobic, and dissolve very poorly
in water. To transport O2 and CO2
around the circulatory system, it must
be reversibly bound to the heme group
in hemoglobin of red blood cells. CO2
dissolves in water to form carbonic acid.
Solvent properties of water
h
t
Fats & Fatty
acids
t
p
Fat molecules are entirely
s
:
nonpolar, are larger than
/
/ oxygen and are insoluble in
water. They are carried in
d
2
g
n the blood inside lipoprotein
e
9
7
complexes, which pack
v
d
them up and ship them
u
m
around so that fat doesn’t
g
n coalesce into bulky droplets.
3
.
c
l
o
u
d
Lipoproteins are composed of a single layer of
f
r
ophospholipids on the outside and fats inside.
n
t The hydrophilic phosphate heads of the
.
n phospholipids face outwards and are in
e
t
contact with water in the blood plasma. The
/
a
hydrophobic hydrocarbon tails face inwards
p and are in contact with the fats.
Solvent properties of water

Steroid Most hormones (e.g.

hormones estrogen, testosterone,

progesterone etc.) are
based on a steroid
backbone derived from
cholesterol and are
largely hydrophobic
and non-polar and do
not dissolve in water.

Transport in the blood

occurs with hormones
bound to proteins.
Summarizing the solubility of molecules in blood
Molecule Chemical property Soluble/insoluble
in blood/water
Polar due to hydroxyl groups (OH-groups) which cause Soluble
Glucose
water molecules to form hydrogen bonds with it.
If hydrophilic or not depends on the R-group. Some are Mostly soluble
Amino Acids charged, some polar, some nonpolar. Due to the nature of
AA forming zwitterions, all are soluble to a certain degree.
The entire structure is nonpolar/without a charge, except Insoluble
Cholesterol on OH group. This provides a small amount of polarity, but
not sufficient (in relation to size of the molecule).
Fats & lipids Entirely non-polar Insoluble
Entirely non-polar as a molecule, solubility depends on the Very weakly
Oxygen temperature (cold water – better solubility). soluble in water
Polar molecule due to cations (Na+) & anion (Cl-) which Soluble
are held together by an ionic bond. The ions are
Sodium chloride
surrounded by polar water molecules when dissolved in
water.
Physical properties - Buoyancy
Buonyancy is the vertical upwards
force exerted by a liquid or gas on
an object which is placed in or on
it. When the (buoyant) force which
water exerts on a body is equal to
the weight of the object, it floats.

http://www.physicsimplified.com/2016/08/24-buoyancy-force-upthrust-due-to.html
Physical properties - Buoyancy
Buoyancy depends on object density.
Living organisms have an overall
density close to water and tend to
float, making water a suitable
habitat. This makes it easier for them
to use water as a habitat – it requires
Object density = fluid density Object density < fluid density Object density > fluid density
less energy to float.

Ice is less dense than

water and floats at the
surface, becoming the
barrier that protects the
liquid water below from
the colder air. This way,
invertebrates can survive
the cold winter months. This means that ice forms an
insulating blanket over water.
Physical properties - Buoyancy h
t

Bony fish have an air-filled swim bladder t

p

which they use to control their overall density. s

:
/
/
w
w
w
.

Photosynthesizing cyanobacteria have r

e

gas vesicles which they use to adjust s

e

how close to the surface they float. a

r
c
h
g
a
t
e
.
n
e
t
/
f
i
g
u
r
e
/
G
Buoyancy in air is much less than in a

water, which is why organisms have s

-
to generate lift to stay airborne and v
e
have bones which are light so that s
i
https://www.chegg.com/learn/physics/introduction-to-physics/swim-bladder-in-fish they become more buoyant. c
 Physical properties -
Viscosity
Viscosity is the resistance of a fluid to High viscosity means more friction
flow. It is due to internal friction caused and high resistance to flow
when one part of a fluid moves relative to
another part and usually the consequence
of the type of bonding within the
substance, or solutes which are dissolved.
Less More viscous
viscous

https://wiki.anton-paar.com/ch-de/grundlagen-der-viskositaetsmessung/##data-imagegroup-47192
 Physical properties -
Viscosity
Viscosity depends on the types of
bonds or forces of attraction
between particles. In liquids,
water has relatively weak forces
of attraction compared to olive oil
or honey so viscosity is low.
h
A fluid moving relative to a body
t
t exerts a drag force on the body, partly
p
:
/
because of friction caused by
/
viscosity.
Compare the
e
c
o
u
r
viscosity of air and
water and how
s
e
s

animals adapt to it:

o
n
l
i
n
e
.
i
a
s
r
i
Physical properties – Specific heat capacity
It takes a lot of energy for the temperature of water to change, while
h
t

the temperature of air changes much faster.

t
p
Specific heat capacity
:
/
/ is the amount of
c
h energy needed to
e
m change the
w
i temperature of 1g
k
i water by 1 C is 4.18
.
u J.
c
d
The specific heat
a
v
capacity of water is
i
s
very high. This is due
.
e
to the hydrogen bonds
d
u
which restrict
/
@
molecular motion
a
p
(and avg kinetic
i
/
energy). For a change
d
e
in temperature to
k
i
occur, hydrogen bonds
/
f
must be broken.
 h

Physical properties – Specific heat capacity t

t
p
s
:
/
/
m
a
k
e
a
g
i
f
.
c
o
m
/
g
i
f
/
w
a
t
e
r
-
h
e
a
t
i
n
g
-
c
u
r
v
e
Physical properties – Specific heat capacity h
t
t
p
s
Air heats up easily, because Water has a higher specific heat :
/
the specific heat capacity is capacity and does not heat up so /
w
low. It takes little energy to easily, it takes more energy to w
w
heat up 1g of air by 1°C. heat up 1g of water by 1°C .
s
u
p
e
r
p
r
o
f
.
c
o
.
u
k
/
r
e
s
o
u
r
c
e
s
/
a
c
a
d
e

How could this property be useful for leaving organism? m

i
c
/
Physical properties – Specific heat capacity
Because of the high specific heat capacity, the temperature of large bodies
of water remains relatively stable, which makes it an ideal habitat for a lot
of organisms which only tolerate a narrow range of conditions.

The temperature of water changes little in

comparison to the temperature of air.

https://upload.wikimedia.org/wikipedia/commons/e/e0/Clouds_over_the_Atlantic_Ocean.jpg
Physical properties – Specific heat capacity
It takes a lot of energy for water to change temperature. This means
that, when water evaporates, a lot of energy is required to break the
hydrogen bonds between water molecules.

Sweating feels as a cooling sensation –

excess heat energy is removed from the Water absorbs a lot
of heat in order to
body because hydrogen bonds are broken evaporate and
as water evaporates (The energy needed to carries away the
heat from the body.
change a substance from liquid into gas is
called the latent heat of vaporization). The
skin and its blood vessels are cooled.
Physical properties – Thermal conductivity
Thermal conductivity is the rate at which heat passes through materials.
The rate at which heat passes through water is relatively high, so in cold
water, warm-blooded animals quickly transfer heat energy to water
loosing energy fast. Air conducts heat less quickly because particles are
less closely together. These materials are therefore insulators of heat.

The speed at which

heat passes through Metals are
materials depends good
on the collision of conductors
particles and of heat.
electrons. https://blog.exair.com/2018/09/12/heat-transfer-3-types/
Physical properties – Thermal conductivity
Gases (air) are usually insulators and
poor conductors of heat, because the
particles are far away apart and
collisions and heat transfer occur
less frequently. In water, the
conductivity is higher, because
particles are closer together.

Marine animals
have adaptations
to prevent heat
energy to be lost to
the surrounding by
conduction.
Physical properties of air and water
The physical properties of air and water are different – mostly
because of their differing densities (air has an 800 times lower
density of 1.2 kg/m-3 compared to water with 997.0 kg/m-3).
Compare the different physical properties in air and water
Ai Water
r

Buoyancy

Viscosity

Thermal
conductivity

Specific
heat
capacity
 t

Physical properties of air and water p

:
/

Ringed seal – a mammal Arctic (black throated) loon – a bird /

t
0
.
g
s
t
a
t
i
c
.
c
o
m
/
l
i
c
e
n
s
e
d
-
i
m
a

How do the physical properties of air

g
e
?
and water in respect to viscosity, q
=
buoyancy and thermal conductivity t
b
affect the energy requirements and n
:

demands of these two animals? A

N
d
https://www.ecomare.nl/en/in-depth/reading-material/animals/seals/ringelrob/ 9
Physical properties of air and water
Complete the table to compare animal adaptations to the physical properties of air and water
The mammal: Ringed seal (Pusa hispida) The bird: Arctic loon (Gavia artica)

Adaptatations Adaptations

Buoyancy

Viscosity

Thermal
conductivity

Specific heat
capacity
Physical properties of air and water
Complete the table to compare animal adaptations to the physical properties of air and water
The mammal: Ringed seal (Pusa hispida) The bird: Arctic loon (Gavia artica)

Adaptatations Adaptations
• Floating is difficult because seals are heavy but assisted by • Big airy feathers make wings very buoyant in air when
the large fat storage (blubber) under the skin which is less flying
dense and makes the seal more buoyant. • Buoyancy in water is aided by air sacs which can be inflated
Buoyancy and which keep the loon on the surface of water.
• For diving, air sacs can be compressed
• Denser, heavier bones than what birds normally have help
with reducing buoyancy to help with diving.

• Heavy body weight so not much effort is needed when • Powerful muscles in legs help with diving
penetrating the viscosity of water. • Webbed toes for effective swimming with powerful strokes
• Streamlined bodyshape reduces drag when swimming • Torpedo-like body shape (hydrodynamic)
Viscosity • In air perfectly sized wings help with uplift because viscosity
• Flippers to propel themselves forward
is lower
• Fast flapping of wings helps with keeping loons in air

• Heat from the seal is easily conducted to water • Thick dense body feathers help to keep the loon
Thermal • A thick layer of blubber below the skin provides insulation waterproof
conductivity against the cold temeprature in water and on ice. • Oil from oil glands in the skin acts as insulator
• Thick plumage helps against cold air temperatures

• Water is used as a stable habitat • Water is a stable habitat due to the high specific heat
Specific heat • Ice caves can be used as lairs and nesting sites, because capacity.
 e

Extraplanetary origin of water on Earth -

e
n
v

There is a lot of water on Earth – where

i
r
o

does
Scientists believe it have
that water sourcesits origin?
on Earth are a consequence of
n
m
e

asteroid collision, which have taken place in the first few 100 n
t

million years after Earth’s formation. These asteriods most likely

-
3
7

also contained a lot of water in the form of hydrated minerals. 6

4
7
0
4
9
 c

Extraplanetary origin of water on Earth u

s
.
c
o

Watch this video and answer the questions on your sheet. m

/
s
p
a
c
e
/
s
p
a
c
e
-
r
o
c
k
s

https://www.youtube.com/watch?v=vjDnh7zfO98
Extraplanetary origin of water on Earth
For water to stay on Earth (or any planet) after its appearance, it must be at the right temperature,
as if the temperature is to high water would evaporate. If it were too low, all the water would
freeze. The right temperature is therefore the one which allows water to stay at a liquid zone. The
temperature is determined by the distance of a planet away from a star.

Goldilock
zone

The habitable zone is often referred to as the Goldilock zone, after the Goldilock fairy tale
Extraterrestrial life and the presence of water

Planets in the Goldilock zone (the habitable zone) often show a presence of water or an
atmosphere. However, this relationship does not automatically imply the existence of life.
Extraterrestrial life and the presence of water
When astrobiologists
search for signs of life on
distant planets, the look for
evidence of water. Why?

https://science.nasa.gov/exoplanets/habitable-zone/

Read the article and

discuss why a planet in
the habitable zone is not
necessarily a place for
extraterrestrial life.
https://1drv.ms/b/s!Au8ZKE_EDcrQjolYW46pTiQlBvtdEg?