Unit 3
Weather Dynamics
CHAPTER 13

Time lapse

https://www.youtube.com/watch?v=XD0_LVWasuA
A Closer Look At Earth
The Earth (Important Stuff)
The earth is tilted on a rotating
axis by 23.5o (the axis is a line
from N to S pole).
 70% of the earth’s surface is
water. 320 million cubic miles.
 Has an atmosphere that
contains air, water vapor,
particles of dust and
chemicals. These all influence
weather.

Global Geography
Global Geography
Global Geography
Weather and Climate
 Weather
– is a set of
environmental conditions
encountered from day to
day.
 Climate
– is a set of
environmental conditions
averaged over many
years.
Earth’s Energy Balance
(Section 13.2)
What do the following images have in
common?`
Earth’s Energy Balance (Section 13.2)
 Almost
all of earth’s
energy comes from the
sun.
 Without it life could not
exist.
 The amount of energy
entering the earth is
balanced with energy
leaving.
Earth’s Energy Balance (Section 13.2)
 Almost
all of earth’s
energy comes from the
sun.
 Without it life could not
exist.
 The amount of energy
entering the earth is
balanced with energy
leaving.
 The
amount of
energy entering
the earth is
balanced with
the energy
leaving it.
Simple diagram:
 This
balance is very
important:
 keeps
earth’s average
surface temp. at 15oC
 Water
(s, l, g)
 Wide
exist.
in all three states
variety of life can
Energy Transfer
 Energy
can be transferred in four different ways:
I.
Radiation
II.
Conduction
III.
Convection
IV.
Advection
(They are all important in
understanding weather.)
1) Radiation
 Energy
transferred by
movement of waves
 Does
not require a
medium (air, water, etc)
Can
therefore travel
through space!
There are different types of radiation. Note the
electromagnetic spectrum on page 504.
UV
radiation, Radio waves, visible light
2) Conduction
 Energy
transferred
when particles collide
in a solid.
 Happens
metals.
fastest in
3) Convection
 Vertical
energy transfer in
fluids (liquids and gases)
4) Advection
Horizontal energy transfer
in fluids (liquids and gases)
Reflection and Absorption of Energy
 What
happens to the
radiant energy from the
sun that reaches the
earth?
*note the relative amounts
in Fig. 4, p. 506
Two factors affect the amount of heat that can
be absorbed by an object:
i) Albedo: (again) the
amount of energy
reflected by a substance
High albedo = snow
Low albedo = dirt
ii) Heat capacity: the amount of
energy needed to raise the temp. of
1kg of material by 1oC.
 Higher
heat capacity = more energy
needed to increase temp so it holds
more energy.
 High
heat capacity materials can
really influence weather!

Figure 5, p. 506
Heat Sinks: Objects that absorb a lot of
energy and become warmer.
 Water
= high heat capacity = good
heat sink
 rock/soil = low heat capacity = poor
heat sink
Which will heat up and cool down more
slowly??
Questions
p. 507 1, 3, 4, 5, 6, 7, 8, 10
p 540 3

Four types of energy transfer
 Radiation,

Conduction, Convection, Advection
Energy being transferred is absorbed by objects. Two
factors affect this absorption:
 Albedo
 Heat
capacity
**Not notes!!!!** Discussion purposes
Ocean and Atmosphere as heat sinks

Two main heat sinks on earth:

Ocean

Atmosphere

Heat Capacities are given in
joules/kilogram/kelvin (elaborate)

Water = 3993 J/kg/K

Air = 1005 J/kg/K

(Granite, a rock, is only 790 J/kg/k)

Common Materials
Ocean and Atmosphere as heat
sinks


Ocean is the main heat sink
on earth for two reasons:

It takes about 4 x more
energy to heat up 1 kg of
ocean than 1 kg of air.

There is more mass of water
than mass of air on earth.
The ocean (and lakes, ponds
etc) store energy and release
it slowly. This affects our
climate and life on earth as
we will see.
Kinetic Molecular Theory

All matter is made of particles. These particles are in
constant motion. They have kinetic energy. (energy of
motion)

The temperature of a substance is the average kinetic
energy of the particles in that substance.
 Higher
temperature  particles moving faster (more energy)
 Lower
temperature  particles moving slower (less energy)

Heat (thermal energy)is the total amount of kinetic energy
in a substance.

Heat transfers from warmer objects to colder objects.
 As
particles collide, energy is transferred.
Heat vs Temperature:
Diagram of 2 beakers
Latent Heat

Latent Heat
 The
amount of heat gained or lost when a material
changes state (solid, liquid, gas).
 Two
important types of Latent heat:
 Latent
Heat of Fusion: amount of heat
(energy) required to convert 1kg of ice to
1kg of liquid water.
 Latent
Heat of Vaporization: amount of
heat (energy) required to convert 1kg of
liquid water to 1kg of water vapour (gas).
A
substance absorbs energy when
changing from:
 solid
 liquid
 Liquid
 Gas
It
takes energy to overcome the
attractive forces between particles.
This
is NOT increasing the
temperature!

A substance releases energy
when changing from :
 Gas
 liquid
 Liquid  solid
 When
water condenses into
clouds, it releases energy
 This

warms the atmosphere.
In this way the water cycle helps
move energy around the globe.
Latent Heat
Of all known substances:

Water has the highest latent heat of vaporization

Water has the second highest latent heat of fusion
Discuss Lab Results
Diagram (after lab)