Lecture 5

The Earth: Atmosphere The Earth: Atmosphere and Hydrosphereand Hydrosphere

HydrosphereHydrosphere

Water portion of the Earth

¾ of the Earth is covered by water

sustains living things on earth

97% of water is found in the major oceans • Pacific

• Atlantic

• Indian

• Arctic

Adams and Lambert. Earth Science: An Illustrated Guide To Science, 2006. NY: Chelsea House

HydrosphereHydrosphere


WaterWater

made up of 2 hydrogen atoms (H) and 1 oxygen atom (O)

Thus its chemical symbol H2O

Exists as • Solid (ice)

• Liquid

• Gas (water vapor)

Properties of WaterProperties of Water

Polar contains positive and negative spheres

this makes water a good solvent

Dissolution process of forming a homogenous Solution like dissolves like (i.e. polar solvents can only dissolve polar substances)

http://www.marinebiology.org/images/watermolecule.jpg

Properties of Water

Density of water ice is less dense than water

Ice floats in water

Saltwater are denser than pure water

At 25oC, water has a density of 1 g/ml

Water cycleWater cycle


Properties of Water

Heat capacity quantity of heat required to change the

temperature of a substance

heat and temperature are different!

water has a relatively high heat capacity

OceansOceans

largest reservoir

of water

vast and deep


Ocean ProfilingOcean Profiling

SONAR

Sound Navigation and Ranging

Use of sound to study deep-water objects and marine lives

SONARSONAR

Passive Sonar- made use of the sound waves emitted by the deep-water object

Active Sonar- sound is emitted into the ocean and its reflection/echo is studied


Ocean CurrentsOcean Currents

Deep-ocean currents- currents generated due to difference in temperature

Surface currents- currents generated just below the surface of the water

Wave- regular undulation caused by the wind

Wave Properties Wave Properties


TidesTides

Movement of Earth’s water due to its gravitational attraction towards the Sun and the moon

SPRING TIDE

- the gravitational pull of the sun and the moon add up together resulting to very high high tide and and very low low tide.

TidesTides

Neap tide

- the gravitational pull of the sun and the moon counteract resulting to very low high tides and very high low tides.

AtmosphereAtmosphere

gas portion of the earth

A blanket of gases, water vapor and dust surrounding the earth

No exact boundary, it just gets thinner

Air = mixture of gases in the atmosphere

Properties of GasProperties of Gas

it has mass and volume occupies space

it diffuses

expands and compress (change in gas’ volume)

Atmospheric pressure

Pressure – force exerted on a surface divided by its area

Atmospheric pressure Pressure – force exerted on a surface divided by

its area

Is affected by volume, amount of gas and temperature



Boyle’s law relationship between Pressure and Volume

As pressure increases, volume decreases

Direct result of gas’ tendency to diffuse

Charle’s law relationship between temperature and volume

As temperature increases, volume increases as well

Layers of the AtmosphereLayers of the Atmosphere

Divided according to change

in temperature

Temperature changes

with altitude


Composition of Composition of atmosphereatmosphere


Weather and ClimateWeather and Climate

Fickle as a weather.

Weather

- condition of the atmosphere at a given time and place

- interaction of various properties of the atmosphere (temperature, pressure, clouds, precipitation)

- varies

Climate- Average weather conditions in a region

WindsWinds

Movement of air due to difference in temperature

Cold air sinks and warm air floats (recall: density)

example: Land breeze and sea breeze- Land and seawater have different heat capacity

- Seawater has higher heat capacity

- Land heats and cools faster than seawater

Sea breezeSea breeze


Land BreezeLand Breeze


HumidityHumidity

amount of water vapor in the air

humid is somehow synonymous to moist

CloudCloud

water vapor that condenses

around airborne particles

like dust and smoke particles


PrecipitationPrecipitation

Occurs when the air is saturated with too much water vapor

Forms of precipitation: rain, snow, sleet

Weather disturbancesWeather disturbances

Thunderstorms

- bring lightning, thunder and rains

- associated with cumulonimbus clouds

Cyclones in the tropics • Tropical depression

• Tropical storm

• Typhoon

Air pollutantsAir pollutants

Air pollutants DescriptionParticulate matter (suspended particles) Bits of solid matters that are suspended in

the air (smoke and dust)

Carbon Monixide (CO) Results from incomplete combustion of fuelsColorless and oxygen gas that binds with hemoglobin.Prevents Oxygen from being absorbed

Nitrogen Dioxide (NO2) Affects the respiratory tractCause acid rain

Ozone (photochemical smog) Ground level ozone

Ozone depletionOzone depletion

• Ozone is found in the stratosphere

• Protects us from the harmful ultraviolet rays from the sun (UV light)

• Destruction of ozone is associated to the following pollutants:

- CFC (found in refrigerators, hair net sprays)

ReferencesReferences

• Adams and Lambert. Earth Science: An Illustrated Guide To Science, 2006. NY: Chelsea House

• Rabago, Lilia M., et al. Dynamic Science. 2003. QC: vibal Publishing House

Figure for questions 17-20

Technology

Lecture 5