The Sun

Energy from the Sun (Fusion) Energy from the sun is called solar energy. Solar energy is the solar radiation that reaches the earth. This Energy is created by Nuclear Fusion that takes place at the sun’s core. Each second the sun converts about 600,000,000 tons of Hydrogen nuclei into Helium nuclei. When the H converts to He, some neutrons are lost and released as ENERGY that gives off HEAT and LIGHT into our solar system.

Our Sun Corona: outer layer that creates the ‘solar wind’ which can go 800 km/s Temp over 1 million degrees Celsius Photosphere: surface layer responsible for most of visible light about 6,000 degrees Celsius SunFusion

Our Sun Sunspots: cooler areas of surface that appear darker (study of sunspots lead to discovery that the sun rotates) Prominences: ionized gas clouds that are still trapped by electromagnetic field Solar Flares: explosive out burts (1 hour) UV, radio, and x-ray radiation Takes about 1 day to reach Earth photo

Roles the Sun Plays here on Earth: It is a major source of energy. It helps plants to grow. It is part of the water cycle. It dictates the seasons. It controls the weather.

Differential Heating Land and water surfaces absorb heat at different rates Water has a higher capacity for storing heat than land This means the ground will heat up much quicker than water from the same amount of sun radiation Water- heats and cools slowly Land- heats and cools quickly

Photosynthesis Solar energy is transferred to chemical energy through photosynthesis Occurs in plants, algae, and some bacteria Convert carbon dioxide and water using energy from the sun to sugar (chemical energy)

The Sun’s Energy Electromagnetic Radiation: heat energy from the sun Radiation is emitted throughout the electromagnetic spectrum at the speed of light, whether or not we can see it. The shorter the wavelength, the higher the energy. Solar radiation is composed of: 40% at wavelengths of infrared (IR) or longer 50% at visible wavelengths 10% at wavelengths of ultraviolet (UV) or shorter (think: skin penetration)

The Sun’s Energy The Sun also emits other types of radiation such as X-rays and cosmic rays These rays are absorbed by Earth’s atmosphere before they reach Earth

How bright? about 4 x 1026 Watt light bulb Releases all waves of light

How Sun’s Energy is Transferred Conduction occurs when energy is transferred from earth’s surface air to atmospheric air. Convection occurs as pockets of air near earth’s surface are heated, become less dense, rise, cool, and sink. Then heated and cycle over again. How Sun’s Energy is Transferred Solar radiation is radiant energy emitted by the sun, particularly electromagnetic energy.

Electromagnetic radiation (spectrum) Gamma rays - fastest X-rays Light Electromagnetic radiation (spectrum) Gamma rays - fastest X-rays UV rays Visible spectrum (ROYGBIV) Infrared waves Radio waves – slowest Electromagnetic Spectrum: The arrangement of these waves according to their wavelengths and frequencies

Types of Radiation The types of radiation are determined by the length of their waves Short wave lengths (shorter than light waves): Ultraviolet rays X rays Gamma rays

Types of Radiation Longer Wavelengths include: Infrared Radio waves **All of these types of radiation are called electromagnetic waves

Energy and Earth’s Atmosphere 1st the upper atmosphere (oxygen and nitrogen) absorbs the short wavelengths of x rays, gamma rays and ultraviolet rays Occurs in thermosphere and mesosphere 2nd in the stratosphere ultraviolet rays are absorbed and react with oxygen to form ozone 3rd some ultraviolet radiation reaches Earth and can cause sunburn

Energy and Earth Most solar rays that reach earth have a longer wavelength (visible and infrared rays) Infrared radiation are absorbed by carbon dioxide, water vapor etc. in the troposphere We receive most visible light rays

Totals of Solar Energy ~ 20 % of energy is absorbed by the atmosphere ~30% is scattered back to space ~50% is absorbed by Earth’s surface Depends on what type of surface the ray hits (water, desert, grass, snow etc.)

Solar Winds The sun also creates solar winds. They are a continuous stream of electrically charged particles that are given off by a magnetic field around the sun.                 It takes a solar wind about 4.5 days to reach Earth.

So why don’t we burn up? The earth has a magnetic field that protects us by deflecting the solar winds. You can even see the interaction between our magnetic field and the solar winds when auroras are created. The most famous are in the northern hemisphere and called the aurora borealis. Auroras also appear on other planets with magnetic fields.

Sun Diagram Draw the diagram of the Sun Label, Color, and describe each part