The Atmosphere

WHEN WE THINK OF HEAT AND TEMPERATURE, WE OFTEN THINK THEY ARE THE SAME THING. THEY ARE RELATED, BUT DIFFERENT. WHEN WE HEAT SOMETHING UP, THE TEMPERATURE INCREASES. TEMPERATURE IS A MEASURE OF HOW FAST OR SLOW THE MOLECULES IN THE SUBSTANCE ARE MOVING. TEMPERATURE IS A MEASURE OF THE KINETIC ENERGY (ENERGY OF MOTION) OF THE SUBSTANCE.

HEAT IS THE TOTAL ENERGY DUE TO MOLECULAR MOTION. IT DEPENDS ON THE SPEED OF THE PARTICLES (TEMPERATURE), THE MASS OF THE SUBSTANCE, AND THE TYPE OF SUBSTANCE. HEAT WILL FLOW FROM AN OBJECT AT HIGH TEMPERATURE TO AN OBJECT AT LOW TEMPERATURE. IF YOU TAKE TWO OBJECTS THAT ARE AT THE SAME TEMPERATURE AND BRING THEM INTO CONTACT, NO HEAT WILL BE TRANSFERRED.

It is heat that will increase or decrease the temperature. If we add heat, the temperature will become higher. If we remove heat the temperature will become lower. Higher temperatures mean that the molecules are moving, vibrating and rotating with more energy.

SO, WHY ARE WE CONCERNED WITH HEAT AND TEMPERATURE WHEN WE ARE BEGINNING TO STUDY THE ATMOSPHERE?

SO, WHY ARE WE CONCERNED WITH HEAT AND TEMPERATURE WHEN WE ARE BEGINNING TO STUDY THE ATMOSPHERE? HEAT FUELS THE MOVEMENT OF THE ATMOSPHERE. TEMPERATURE IS USED TO MEASURE THAT ENERGY.

THE TWO TEMPERATURE SCALES WE USUALLY USE ARE FAHRENHEIT AND CELSIUS (CENTIGRAGE). oC = (5/9)(oF - 32) oF = (9/5)oC + 32

THERE IS ALSO THE KELVIN SCALE. THIS IS BASED ON ABSOLUTE ZERO. ABSOLUTE ZERO IS THE TEMPERATURE AT WHICH ALL MOLECULAR MOTION STOPS. IT IS THE LOWEST TEMPERATURE POSSIBLE. ABSOLUTE ZERO IS - 273oC. oK = oC + 273

oF oC oK Water boils 212o 100o 373o Room temp. 72o 23o 296o Water freezes 32o 0o 2730 Absolute zero -460o -273o

Our concern with temperature and heat has to do with the way the earth is heated by the sun. Because the earth is tilted 23.5o on its axis, the earth is not heated evenly by the sun. Also, since we have night and day, different parts are heated differently.

WHAT IS THE ATMOSPHERE?

WHAT IS THE ATMOSPHERE? THE LAYER OF GASES SURROUNDING THE EARTH AND HELD BY GRAVITY. THE ATMOSPHERE SUPPORTS LIFE ON EARTH. IT ABSORBS SOLAR RADIATION . IT PROTECTS US FROM HIGH ENERGY RADIATION AND THE FRIGID VACUUM OF OUTER SPACE. IT TRANSFERS HEAT FROM WARM AREAS TO COLDER AREAS.

THE COMPOSITION OF THE ATMOSPHERE IS: 78% NITROGEN 21% OXYGEN 1% ARGON 0.038% CARBON DIOXIDE THIS COMPOSITION IS KEPT IN BALANCE BY LIFE ON EARTH. IT HAS VARIED OVER GEOLOGIC TIME.

OTHER IMPORTANT GASES ARE WATER VAPOR AND OZONE. THE AMOUNT OF WATER VAPOR WILL VARY WITH TEMPERATURE. AS THE TEMPERATURE INCREASES, THE AIR CAN HOLD MORE WATER VAPOR.

THE NORMAL MOLECULAR FORM OF OXYGEN IS O2. OZONE IS A LESS STABLE FORM OF OXYGEN, AND ITS FORMULA IS O3. IN THE STRATOSPHERE, OZONE ABSORBS HARMFUL UV RADIATION. IF THE OZONE LAYER DID NOT EXIST, LIFE AS WE KNOW IT COULD NOT EXIST. HOWEVER, OZONE IS VERY REACTIVE. OZONE AT GROUND LEVEL IS DANGEROUS.

GOOD UP HIGH. BAD NEAR BY.

LAYERS OF THE ATMOSPHERE BASED ON HOW THE TEMPERATURE CHANGES, THE ATMOSPHERE IS DIVIDED INTO LAYERS.

TROPOSPHERE - 75% OF THE MASS OF THE ATMOSPHERE IS IN THE TROPOSPHERE. IT EXTENDS FROM EARTH’S SURFACE UP TO ABOUT 10 KM. ABOVE THIS IS A LAYER WHERE THE TEMPERATURE IS RELATIVELY CONSTANT - THE TROPOPAUSE. THE JET STREAM, A FAST MOVING WIND CURRENT, OCCURS IN THE TROPOPAUSE. THE STRATOSPHERE IS THE LAYER ABOVE THE TROPOPAUSE. THE OZONE LAYER IS IN THE STRATOSPHERE, WHICH CAUSES THE TEMPERATURE INCREASE.

THE STRATOSPHERE EXTENDS UP TO ABOUT 50 KM. ABOVE THE STRATOSPHERE IS A THIN LAYER CALLED THE STRATOPAUSE WHERE THE TEMPERATURE IS CONSTANT. ABOVE THIS IS THE MESOSPHERE, WHERE THE TEMPERATURE DECREASES AGAIN TO -100o C. THIS IS BECAUSE THERE IS NO CONCENTRATED LAYER OF OXONE. THE MESOSPHERE GOES FROM ABOUT 50 KM UP TO 80 KM. METEOROIDS USUALLY BURN UP IN THIS LAYER.

THE THERMOSPHERE IS ABOVE THE MESOPAUSE. IN THIS LAYER, THE AIR HEATS UP BECAUSE OF RADIATION. THIS LAYER GOES FROM 80 KM UP. IT CONTAINS THE MAGNETOSPHERE - EARTH’S MAGNETIC FIELD. THE AURORAS OCCUR HERE.

VOCABULARY WORDS HEAT STRATOSPHERE TEMPERATURE OZONE LAYER CELSIUS MESOSPHERE FARENHEIT THERMOSPHERE KELVIN OZONE ATMOSPHERE TROPOSPHERE TROPOPAUSE