Presentation on theme: "The atmosphere S6E4a: Demonstrate that land and water absorb and lose heat at different rates and explain the resulting effects on weather patterns."— Presentation transcript:
1 The atmosphereS6E4a: Demonstrate that land and water absorb and lose heat at different rates and explain the resulting effects on weather patterns.S6E4b: Relate unequal heating of land and water surfaces to form large global wind systems and weather events such as tornados and thunderstorms.
2 Warm Up: Monday February 10, 2014 What happens to the sun’s energy once it reaches earth?
3 Layers of the atmosphere Objectives:Identify the four main layers of the atmosphere.Describe the characteristics of each layer.
4 4 layers of the atmosphere The troposphereThe stratosphereThe mesosphereThe thermosphere
5 The troposphere The lowest layer of the Earth’s atmosphere. This is where we live.The layer of the atmosphere in which Earth’s weather occurs.Air pressure decreases as you rise in the atmosphere.Although the shallowest layer, contains almost all of the mass of the atmosphere.As altitude increases, the temperature decreases.
6 The stratosphereThe second layer of the atmosphere and contains the ozone layer.Extends from the top of the troposphere to about 50 km.The lower stratosphere is cold (about -60 degrees C), the upper is warmer.Why? Because the middle portion contains a layer of air where there is much more ozone than in the rest of the atmosphere. When the ozone absorbs energy from the sun, the energy is converted into heat, warming the air.The ozone layer protects Earth’s living things from dangerous ultraviolet radiation from the sun.
7 The mesosphere The 3rd layer of the atmosphere. Above the stratosphere Marked by a drop in temperature.Begins 50km above Earth’s surface and ends 80 km.In the outer mesosphere temperatures approach -90 degreesThe layer of the atmosphere that protects Earth’s surface from being his by most meteoroids.
8 The thermosphere The outermost layer of Earth’s atmosphere The air is very thin.80km above Earth’s surfaceNo definite outer limit but blends with outer spaceVery hot! Up to 1800 degreesSun strikes the thermosphere first, which causes it to be so hot.Divided into two parts:Ionosphere (lower layer)Exosphere (outer portion)
9 Energy from the sun Where does the heat in the atmosphere come from? Comes from the sunTravels to Earth as electromagnetic waves (a form of energy that can move through the vacuum of space)These are classified by wavelengthRadiation: a direct transfer of energy by electromagnetic waves
10 Energy from the sunMost of the energy from the sun travels to Earth in the form of visible light and infrared radiation. A small amount arrives as ultraviolet radiation.
11 Includes all of the colors you see in the rainbow Visible lightIncludes all of the colors you see in the rainbowRed, orange, yellow, green, blue, indigo and violetDifferent colors = different wavelengths
12 Non-visible radiation Infrared radiation: one form of electromagnetic energy that has wavelengths that are longer than red lightNot visible but can be felt as heatUltraviolet radiation: Given off by the sunAn invisible form of energy with wavelengths that are shorter than violet wavesCan cause sunburns, skin cancer and eye damage
13 Energy in the atmosphere Some sunlight is absorbed or reflected by the atmosphere before it can reach the surface. The rest passes through the atmosphere to the surface.Some solar radiation is absorbed in the atmosphereOzone layer absorbs most ultraviolet radiationSome sunlight is reflectedClouds reflect light back into spaceScattering: dust particles and gases in the atmosphere reflect light in all directions – looks bluer than ordinary light (sky)
14 Energy at earth’s surface Some of sun’s energy reaches Earth’s surface and is reflected back into the atmosphereAbout half is absorbed by the land and water and changed to heatWhen Earth’s surface is heated, it radiates most of the energy back into the atmosphere as infrared radiation.This is absorbed by water vapor, carbon dioxide, methane and other gases in the air.This energy hats the gases in the airGases form a “blanket” around Earth that holds heat in the atmosphere – this process is called the greenhouse effect
15 Heat transfer – thermal energy and temperature Thermal energy: the total energy of motion in the particles of a substanceAir temperature is usually measured with a thermometerThermometer: thin glass tube with a bulb on one end that contains a liquidTemperature is measured in degreesTwo temperature scales:Celsius – freezing 0 degrees, boiling 100 degrees (scientists use this)Fahrenheit scale – freezing 32 degrees, boiling 212 degrees
16 How heat is transferred Heat: transfer of thermal energy from a hotter object to a cooler objectHeat is transferred in three ways within the atmosphere: radiation, conduction, and convection
17 radiation Direct transfer of energy by electromagnetic waves Ex: warmth of the sun’s rays on your face – this energy was directly from the sun as radiation.
18 ConductionThe direct transfer of heat from one substance to another substance that it is touchingEx: spoon in a pot of soupEx: foot on sand on beach
19 convection The transfer of thermal energy by the movement of a fluid In liquids and gases, particles move easily from one place to anotherAs they move, their energy goes along with themCaused by the difference of density
20 Heating the troposphere Radiation, conduction and convection work together to heat the troposphereDuring the daytime – sun’s radiation heats the surfaceLand becomes warmer that the airAir near surface heated by both radiation and conductionOnly first few meters of troposphere by conductionAir close to ground warmer than a few meters up
21 Heating the troposphere Troposphere heated mostly by convectionair near ground heats and spreadsCooler, denser air sinks toward surface, forcing the warmer air to riseAs the warm air rises and cools, becomes more dense and sinks where it may be heated once again.This forms convection currents – upwards movement of warm air and the downward movement of cool airConvection currents move heat throughout the tropsphere