UNIDAD AICLE 2º ESO CIENCIAS DE LA NATURALEZAUNIT: SUN’S ENERGYOBJETIVOSCONTENIDOS ( CONTENTS)­ El Sol : Sun’s Structure­ El desigual reparto de la energía solar: The Atmosphere is our shield,The incidence of the solar radiation on Earth­Dinámica atmosférica a escala local ( Local dynamic atmosphere: land and sea breezes, valley andmountain wind, convection process, temperature inversion)­ Tiempo y clima : Weather and climate­Dinámica atmosférica a gran escala: Global dynamic atmosphere ­ winds, clouds and rain­ El uso de la energía solar.: SOLAR POWER­ Los riesgos de la energía solar: BE CAREFUL WITH THE SUN: Skin cancer

INTRODUCTIONThe sun is a star. A star does not have a solid surface, but is a ball of gas (92.1 percent hydrogen (H2) and 7.8

percent helium (He)) held together by its own gravity.

The sun is the center of our solar system

Without the sun's intense energy there would be no life on Earth.

SUN’S STRUCTUREThe core (the central region where nuclear reactions consumehydrogen to form helium. These reactions release the energy that

ultimately leaves the surface as visible light. ),

the radiative zone (extends outward from the outer edge of

the core to base of the convection zone, characterized by the

method of energy transport ­ radiation),

and the convection zone (the outer­most layer of the solar

interior extending from a depth of about 200,000 km to the

visible surface where its motion is seen as granules and

supergranules. ).

The solar atmosphere is made up of: the photosphere (the visible surface of the Sun),

the chromosphere (an irregular layer above the photosphere where the temperature rises from 6000°C to about

20,000°C),

a transition region (a thin and very irregular layer of the Sun's atmosphere that separates the hot corona from the much

cooler chromosphere),

and the corona (the Sun's outer atmosphere.).

Beyond the corona is the solar wind, which is actually an outward flow of coronal gas. The sun's magnetic fields rise through theconvection zone and erupt through the photosphere into the chromosphere and corona. The eruptions lead to solar activity,which includes such phenomena as sunspots, flares, prominences, and coronal mass ejections.

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REMEMBER: star solar system Earth Sun photosphere chromosphere transition region corona solar wind

Activity 1: Write the sun’s layers

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THE ATMOSPHERE IS OUR SHIELD

Speaking practice: Why the atmosphere is our shield?

The Earth's atmosphere is a thin layer of gases that surrounds the Earth. It composed of 78% nitrogen, 21% oxygen, 0.9% argon, 0.03% carbon dioxide, and trace amounts of other gases. This thin gaseous layer insulates the Earth from extreme temperatures; it keeps heat inside the atmosphere and it also blocks the Earth from much of the Sun's incoming ultraviolet radiation.

THE INCIDENCE OF THE SOLAR RADIATION ON EARTH

The shape of the Earth directly affects the amount of solar radiationreceived during certain segments of its revolution around the sun.Equatorial regions receive more direct rays of the sun, thus moresolar radiation. Moving farther south or north of the equator willchange the angle at which the rays strike the Earth, thusdecreasing the amount of solar radiation received at that latitude.

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LOCAL DYNAMIC ATMOSPHERELAND AND SEA BREEZES

day

Land and sea breezesTerrain features such as mountains, valleys and shorelinesgenerate local wind. During the day, the land is warmer than thesea; therefore the wind blows from the cooler water toward thewarmer land. This is called a sea breeze. At night, the windreverses as the land cools more quickly than the watergenerating a land breeze.

night

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VALLEY AND MOUNTAIN WIND

The mountain and valley breezes are also diurnal. The radiated ground heats air next to a mountain slope in the daytime. Colder, denser air farther away from the mountain slope located at the same altitude as the warmer air settles down upon the warmer air forcing it to move up the mountain slope. This is referred to as a valley wind because it flows up the mountain slope out of the valley. At night, the opposite movement occurs. The air on the mountain slope is cooled, becomes heavier than the surrounding air and follows the mountain slope down into the valley. Mountain winds are usually stronger than valley winds.

CONVECTION PROCESS

Variation in the temperature comes from uneven heating of the Earth's surface by the Sun. The warmer air expands becoming less dense than the cooler air around it. The cooler air (which has greater density) moves toward the ground. The rising air spreads out above, becomes cooler and eventually descends while the cooler air below warms and rises. This process of convection plays itself out worldwide from hemispheric circulations to local airflows. Horizontal movement of the air is known as wind.

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ACTIVITY: Explain how an aerostatic globe flies.

TEMPERATURE INVERSION

It is a reversal of the normal behaviour of temperature in the troposphere (the region of the atmosphere nearest the Earth’s surface), in which a layer of cool air at the surface is overlain by a layer of warmer air. (Under normal conditions air temperature usually decreases with height.).An inversion acts as a cap on the upward movement of air from the layers below. As a result, convection produced by the heating of air from below is limited to levels below the inversion. Diffusion of dust, smoke, and other air pollutants is likewise limited.

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WEATHER AND CLIMATEWhat’s the weather like today in the world?Watch and play : http://learnenglishkids.britishcouncil.org/es/fun­games/whats­the­weather

Speaking practice: Do you know the difference between weather and climate?

Weather is considered to be the atmospheric conditions that are happening now or within a few days. On the other hand, Climate represents the long term atmospheric patterns within which weather occurs. As the popular saying goes, "Climate is what you expect, and weather is what you get!".

VOCABULARY: WEATHERActivity :Use this link and matchhttp://www.educa.jcyl.es/educacyl/cm/gallery/recursos_educativa/ingles_tiempo/pdf/OA3_weather_vocabulary.pdfActivity: Link with the definitionhttp://www.weather.com/glossary/Activity : Imagine that you are the weather man/ woman and you have to say the weather on thenews. Write a short script about it.

Activity: Draw a comic weather joke. You have an example below.

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GLOBAL DYNAMIC ATMOSPHERE

WINDSWhat is wind?

Wind is air in motion. It is produced by the uneven heating of the earth’s surface by the sun. Since the earth’s surface is made of various land and water formations, it absorbs the sun’s radiation unevenly. Two factors are necessary to specify wind: speed and direction.

What causes the wind to blow?As the sun warms the Earth's surface, the atmosphere

warms too. Some parts of the Earth receive direct rays from the sun all year and are always warm. Other places receive indirect rays, so the climate is colder. Warm air, which weighs less than cold air, rises. Then cool air moves in and replaces the rising warm air. This movement of air is what makes the wind blow.

HIGH PRESSURE OR ANTICYCLONEIn an anticyclone (also referred to as a 'high') the winds tend to be light and blow in a clockwise

direction. Also the air is descending, which inhibits the formation of cloud. The light winds and clear skies

can lead to overnight fog or frost. If an anticyclone persists over northern Europe in winter, then much of the

British Isles can be affected by very cold east winds from Siberia. However, in summer an anticyclone in the

vicinity of the British Isles often brings fine, warm weather.

LOW PRESSURE OR DEPRESSION

In a depression (also referred to as a 'low'), air is rising. As it rises and cools, water vapour

condenses to form clouds and perhaps precipitation. Consequently, the weather in a depression is often

cloudy, wet and windy (with winds blowing in an anticlockwise direction around the depression). There are

usually frontal systems associated

with depressions.

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CLOUDS

What are clouds?A cloud is a large collection of very tiny droplets of water or ice crystals. The droplets are so small

and light that they can float in the air.

How are clouds formed?All air contains water, but near the ground it is usually in the form of an invisible gas called water

vapor. When warm air rises, it expands and cools. Cool air can't hold as much water vapor as warm air, so some of the vapor condenses onto tiny pieces of dust that are floating in the air and forms a tiny droplet around each dust particle. When billions of these droplets come together they become a visible cloud.

RAINHow does rain form?

Water droplets form from warm air. As the warm air rises in the sky it cools. Water vapor (invisible water in the air) always exists in our air. Warm air holds quite a bit of water. For example, in the summer it is usually very humid. When enough of these droplets collect together, we see them as clouds. If the clouds are big enough and have enough water droplets, the droplets bang together and form even bigger drops. When the drops get heavy, they fall because of gravity, and you see and feel rain.

What causes rain?When clouds develop or rain occurs, something is making the air rise. Several things can make this

happen. Mountains, low­pressure areas, cold fronts, and even the jet stream.

ACTIVITY: VIDEO WHAT IS PRECIPITATION? http://www.youtube.com/watch?v=­XvT4F2Fer4

ACTIVITY: SPEAKING: What’s the weather today? Make your weather’s prediction.

SOLAR POWERSolar power is energy from the sun. "Solar" is the Latin word for "sun" and it's a powerful source of energy. Without it, there will be no life. Solar energy is considered as a serious source of energy for many years because of the vast amounts of energy that is made freely available, if harnessed by modern technology.

Sunlight, or solar energy, can be used for heating, lighting and cooling homes and other buildings, generating electricity, water heating, and a variety of industrial processes.

It is considered 'Renewable Energy' because…-The technology used to convert the sun's power into electricity does not produce

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smoke (carbon dioxide and other air pollutants).Tapping the sun's energy does not usually destroy the environment.Unfortunately, the sun does not available in the night, and in some days, clouds and rains and other natural conditions prevent the sun's powerful rays to reach us. This means that it is not always available. This a why we cannot rely on solar energy alone.

Solar cellsSolar cells are devices that convert light energy directly into electrical energy. In these cells, there are semiconductors (silicon alloys and other materials). You may have seen small solar cells on calculators or some mobile phones. Larger arrays of solar cells are used to power road signs, and even larger arrays are used to power satellites in orbit around Earth. Solar cells are also called photovoltaic cells or PV devices.

Solar panelsSolar panels are different to solar cells. Solar panels do not generate electricity directly. Instead they heat up water directly. A pump pushes cold water from a storage tank through pipes in the solar panel. The water is heated by heat energy from the Sun and returns to the tank. They are often located on the roofs of buildings where they can receive the most sunlight.

There is also the Solar Thermal Power Plant. Here, a concentration of the sun's energy by many panels is used to heat up water into steam, which is then used to turn turbines to produce electricity.

Guess what! Power stations of this nature usually need a lot of space to capture a lot of the sun's energy!

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The Parabolic Trough System uses this kind of system. Here, troughs are designed to direct the sun's energy to absorber tubes as long as the sun is up.

Many of these Parabolic troughs are installed to collect massive energy for the rods to heat water to turn turbines.

Other less common methods that use the Solar Thermal Power Plant system are the Solar Dish and The Solar Power Tower

ACTIVITY: Solar energy can be used for what?

BE CAREFUL WITH THE SUN: Skin cancer

What causes skin cancer?The main cause of skin cancer is exposure to ultraviolet (UV) radiation. The sun produces UV radiation but it can alsocome from other sources, such as solarium tanning machines.Most parts of Australia have high levels of UV radiation all yearround.

This radiation cannot be seen or felt but can cause: sunburn skin and eye damage premature ageing of the skin damage to the skin cells, which leads to skin cancer.

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RECURSOS ( RESOURCES)http://bilingualiliberis.wikispaces.com/AICLE+SCIENCE+2%C2%BA+ESO ( La ud 7 esla misma)http://www.nasa.gov/mission_pages/sunearth/multimedia/Sunlayers.htmlhttp://solarsystem.nasa.govhttp://virtualskies.arc.nasa.gov/weather/3.htmlwind: valley and mountain breezes. Art. Britannica Online for Kids. <http://kids.britannica.com/comptons/art-54145>.

http://www.guiafe.com.ar/argentina-pictures/

http://www.britannica.com

http://www.maricopa.gov/aq/media/images/jpg/aq_graphic.jpg

http://www.nc-climate.ncsu.edu

http://learnenglishkids.britishcouncil.org/es/fun­games/whats­the­weather

http://www.weatherwizkids.com/weather-jokes-Amanda.jpg

http://www.weatherwizkids.com/http://www.metoffice.gov.uk/education/teachers/in-depth/understanding

http://www.eschooltoday.com/energy/renewable-energy/solar-energy.htmlhttp://environment.about.com/od/renewableenergy/tp/renew_energy.htm

http://www.cancervic.org.au/about-cancer/cancer_types/skin_cancers_non_melanomahttp://www.ucdenver.edu/academics/colleges/PublicHealth/research/ResearchProjects/Pages/SkinCancerPrevention.aspx

http://web.gccaz.edu/~lnewman/gph111/topic_units/Pressure_winds/pressure/pressure2.html

http://vincentwoodcock.com/marker5.html

http://www.educa.jcyl.es/educacyl/cm/gallery/recursos_educativa/ingles_tiempo/pdf/OA3_weather_vocabulary.pdf

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