Properties of WaterProperties of Water

Specific HeatSpecific Heat

&&

Phase ChangesPhase Changes

Specific HeatSpecific Heat• the amount of energy the amount of energy

required to raise the required to raise the temperature of temperature of 1 gram of a 1 gram of a substance 1°Csubstance 1°C

• Specific heat of Specific heat of liquid water = 1liquid water = 1

• This property of water This property of water is very important!!!is very important!!!

Water heats up more slowly mainly Water heats up more slowly mainly due to its high due to its high Specific HeatSpecific Heat (takes 5 x longer than land) (takes 5 x longer than land)

• Water reflects the sun’s incoming solar radiation

• Therefore, water takes longer to heat up, but will retain this heat longer, so………..

During the day…..During the day…..

A sea breeze will form.A sea breeze will form.

Sea breeze: wind moves from ocean to Sea breeze: wind moves from ocean to landland

At night…At night…A land breeze developsA land breeze develops

Land breeze: wind moves from land to Land breeze: wind moves from land to oceanocean

CLIMOGRAPHS: 30-YEAR AVERAGES (1971 - 2000)

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9.62 7.87 7.37 4.93 3.28 2.57 1.16 1.21 2.61 5.61 10.5 10.4

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AKRON, OH

SAN DIEGO, CA

ABERDEEN, SD

CHARLESTON AP,SC

AKRON, OH

SAN DIEGO, CA

ABERDEEN, SD

CHARLESTON AP,SC

By Charles Burrow s

MODERATING EFFECT OF MODERATING EFFECT OF LARGE BODIES OF WATERLARGE BODIES OF WATER

2 types of Heat Energy2 types of Heat Energy

Kinetic Energy – is energy in motion. Kinetic Energy – is energy in motion. Temperature is the average KE of Temperature is the average KE of moleculesmolecules

Potential Energy – is energy in storage Potential Energy – is energy in storage aka latent heat or hidden energy. Cannot aka latent heat or hidden energy. Cannot be measured with a thermometerbe measured with a thermometer

Change in State (Phase Change)Change in State (Phase Change)

Change in state is a change in potential Change in state is a change in potential energyenergy

Known as latent heat because it does not Known as latent heat because it does not cause a temperature changecause a temperature change

During the phase change energy can be During the phase change energy can be absorbed or released but the energy is absorbed or released but the energy is hidden because it hidden because it DOES NOT SHOW A DOES NOT SHOW A CHANGE IN TEMPERATURECHANGE IN TEMPERATURE

DURING CHANGE OF STATE, ENERGY IS CONVERTED TO POTENTIAL ENERGY OR STORED HEAT – DOES NOT SHOW A CHANGE IN TEMPERATURE

Condensation and freezing – release energy Evaporation and melting – require energy

¾ OF THE ENERGY ABSORBED BY ¾ OF THE ENERGY ABSORBED BY EARTH EVAPORATES WATER FROM EARTH EVAPORATES WATER FROM

THE OCEANSTHE OCEANSEVAPORATION EVAPORATION 540 CALORIES/GRAM GAINED540 CALORIES/GRAM GAINEDThe gram of water absorbed 540 calories of latent The gram of water absorbed 540 calories of latent heat as it changed to vapor (heat as it changed to vapor (require addition of energyrequire addition of energy)) COOLING EFFECTCOOLING EFFECT

CONDENSATIONCONDENSATION 540 CALORIES/GRAM RELEASED540 CALORIES/GRAM RELEASEDThe gram of water released 540 calories of latent The gram of water released 540 calories of latent heat as it changed to liquid (heat as it changed to liquid (give off energygive off energy)) WARMING EFFECTWARMING EFFECT

3. A sample of water undergoes the phase changes from ice to vapor and back to ice as shown in the model below.

During which phase change does the sample gain the greatest amount of energy?

4. According to the Earth Science Reference Tables, how many calories of heat energy must be added to 10 grams of iron to raise its temperature 10° C?

Heat (cal) = mass x temp. change x specific heat 10 g x 10°C x .11 cal/g °C = 11 cal

12. Based on the Earth Science Reference Tables, what is the total amount of energy required to melt 100 grams of ice at 0°C to liquid water at 0°C?

Heat of fusion of water is 80 calories per gram. To melt 100 grams of ice would require 100 times as much

energy or 8000 calories.

Check the box which describes whether energy is gained or lost for each process.

Process Energy Gained

Energy Lost

Condensation

Evaporation

Melting

Solidification

How many calories are gained or lost by water for each of the following processes?

Process Calories Gained

Calories Lost

Condensation

Evaporation

Melting

Solidification