Chemistry Unit Properties of Water and their Relationship - PowerPoint Presentation

Slide1

Chemistry UnitSlide2

Properties of Water and their Relationship

to

Weather and ClimateSlide3

The Three Phases of Water

Solid: Ice

Liquid: Water

Gas: Water VaporWhen water changes phases, a large amount of energy is absorbed or released.Slide4

Theoretically liquid water turns into…

I

ce at 0

oCWhen water turns into ice it gives out a large amount of energyVapor at 100oCWhen water turns into vapor it absorbs a very large amount of energyWhat causes water to change phase? Slide5

0n the Earth

water can turn into

the gas

phase when the temperature is much lower than 100oC.Evaporation can happen at any temperature, but as the temperature increases evaporation increases.Evaporation also relates to the humidity of the air and the availability of water on the ground. If it is over the ocean, then there is plenty of water to evaporate.Humidity: the amount of water vapor in the air. It indicates the likelihood ofPrecipitationDewFog

100% humidity

means

that the air is fully saturated with water

vapor.

What causes water to change phase? Slide6

How

are the

different phases of water

distributed on the Earth?Where are the liquid phases of water?In the oceans (mostly)Where are the solid phases of water?In ice Where are the gas phases of water?In the air98.299% of water is liquid, 1.7% solid, and only 0.001% as gas.Slide7

The distribution of the solid phase of water on the Earth.

Icebergs and other sea ice floating

on the

oceanIce sheets on land Greenland Antarctica Alaska Mountain glaciersSlide8

The distribution of the solid phase of water on the Earth.

Icebergs and other sea ice floating

on the

oceanIce sheets on land Greenland Antarctica Alaska Mountain glaciersSlide9

The distribution of the solid phase of water on the Earth.

Icebergs and other sea ice floating

on the

ocean

Ice sheets on land

Greenland

Antarctica

Alaska

Mountain glaciersSlide10

By

far

most

of the water is in the ocean – 96.5%!The distribution of the liquid phase of water on the Earth.Slide11

Ocean water contains dissolved minerals – “salt”

Salt water is denser than freshwater because of the dissolved salts -

-

the higher the salinity (more salt in the water) the greater the density.Salt water freezes at a lower temperature than fresh water.The higher the salinity the lower the freezing/melting point.Salt water boils at a higher temperature than fresh waterThe higher the salinity the higher the boiling/condensation point.The distribution of the liquid phase of water on the Earth – the oceans.Slide12

Density of seawater

Increases with increasing salinity and decreasing temperature.

Increases with increasing pressure – pressure increases with depth.

Ocean layered according to densityHalocline: Salinity gradientThermocline: Temperature gradientPycnocline: Density gradientThe distribution of the liquid phase of water on the Earth – the oceans.Slide13

Halocline

:

zone of rapid change of salinity with depth.

Dense water is heavy and sinks below less dense layers.The distribution of the liquid phase of water on the Earth – the oceansSlide14

Thermocline: zone in which temperature decreases rapidly with depth.

3 zones in ocean based on temperature variation:

Surface

zoneThermocline Deep zoneNotice that temperature in the deep ocean is similar in low and high latitudes.Changes in the thermocline (e.g., the slope of it) can have a significant influence on global climate.The distribution of the liquid phase of water on the Earth – the oceansSlide15

Pycnocline

: zone in which density increases rapidly with depth.

Thermocline & halocline together make the

pycnocline.The distribution of the liquid phase of water on the Earth – the oceansSlide16

Water vapor in the air is called humidity.

Humidity

:

the amount of water vapor in the airWater vapor content (humidity) decreases with increasing altitude.As the temperature of the air decreases the amount of water vapor (humidity) that can be held in the air decreases.The distribution of the gas phase of water on the Earth – the air.Slide17

How is water

vapor

distributed by latitude?

These different “air masses” move around and cause weather phenomena, such as cold fronts and warm fronts.The distribution of the gas phase of water on the Earth – the air.Slide18

T

emperature, density, and pressure

differences

in the atmosphere:Temperature varies as altitude increases.Density decreases as altitude increases.Pressure decreases as altitude increases.The distribution of the gas phase of water on the Earth – the air.Slide19

What

happens to the gas phase when the vapor rises through the atmosphere and cools down

?

The water vapor will condense creating cloudsWhen the clouds become supersaturated (have a humidity higher than 100%) they form rain (or snow depending on the air temperature).The distribution of the gas phase of water on the Earth – the air.Slide20

The distribution and movement of air with different temperature and water vapor content have significant control over weather conditions.

For example: What

makes a cold

front?Pressure differentialTemperature differenceThe distribution of the gas phase of water on the Earth – the air.Slide21

The distribution of solid, liquid, and gas phases of water affect weather and climate.

The amount and distribution of different

phases of water largely controls the earths weather and

climate:Short-term changes, e.g., in days to months, cause different weather conditions.Long-term changes, e.g., in 10s to 100s of years, cause climate change.Slide22

Let’s

look at the overall budget of water on earth.

Percentage of the phases of water found on Earth

Solid: 1.7%Liquid: 98.299%Gas: 0.001%How does the distribution of solid, liquid, and gas phases of water affect weather and climate?Slide23

What

if this particular balance changes??

Assume

1.7% in ice now. What if 2.7% of the water is in ice? Then there is 1% less water in the ocean. That means sea level is much lower. So what if 0.7% of water is in ice?That means sea level is much higher.

How does the distribution of solid, liquid, and gas phases of water affect weather and climate?Slide24

Let’s think about

what can change

the water budget:

What would increase the amount of solid water on the earth?What would increase the amount of liquid water on the earth?How does the distribution of solid, liquid, and gas phases of water affect weather and climate?Slide25

How does the distribution of solid, liquid, and gas phases of water affect weather and climate?