The Sun and it’s Effects 1-8

The sun’s size average sized yellow star largest in our solar system Diameter=1.4 million km 10 x larger than Jupiter 109x larger than earth

Sun’s make up -about 70% hydrogen and about 28% helium -Remaining 2%- Carbon and Oxygen -The sun makes up 99% of all the mass in our solar system

Structure of the Sun http://www.spacetelescope.org/videos/astro_ac/ Layered Core- central region- made up of plasma fusion reactions occur- hydrogen atoms come together to form helium atoms high temp- above 15 million degrees celsius high pressure Reactions release energy in the form of electromagnetic radiation

Structure of the Sun Radiative zone- layer surrounding the core Temp approx 8 million degrees celsius (can range from 2-8 million) Absorbs thermal energy produced in the core and transfers it as electromagnetic radiation Emits electromagnetic radiation into the outer layer called the convection zone

Structure of the sun Convection zone- outermost layer of the sun Temp. around 2 million degrees celsius Has rising and falling currents of gas called convection cells Currents carry energy into the sun’s atmosphere (first layer- photosphere)

Sun’s Atmosphere 3 layers Photosphere Chromosphere Corona

Sun’s Atmosphere Photosphere innermost layer thinnest layer Temp. around 6000 degrees C Layer that we see- emits visible light

Sun’s Atmosphere Chromosphere- layer above the photosphere Temp- approx. 20,000 degrees C produces most of sun’s UV radiation Thicker than photosphere

Sun’s Atmosphere Corona- top layer Temp. 1 million to 3 million degrees celsius Thickest layer Low density Emits less radiation than other layers

Other Features Granules are the tops of convection cells and give the photosphere a grainy appearance. Sunspots- dark cool areas of the photosphere connected by magnetic fields called prominences

Drawing Time! (left page) Draw a picture of the sun and it’s layers and label it Include the temperature of each layer Include a description of each layer Add the layers of the sun’s atmosphere and label it Include a brief description of each Make sure your layers are the appropriate thickness Add sunspots and show convection currents in the appropriate layers of the sun or atmosphere Color your drawing to clearly show the different layers

Sunspots Temps up to 2000K cooler than the surrounding areas Bright but not as bright as their surroundings which is why they appear dark to us Not permanent they tend to appear and disappear Sunspot activity seems to cycle every 11.2 years Scientists determined that the equator of the sun rotates faster than the poles by observing sunspots

The Magnetic Sun -Images of the Sun reveal loops of hot ionized gas (plasma) above the locations of Sunspots. -The shapes of these loops are just like the loops of force between two opposite poles of a magnetic field. **The plasma acts just like iron filings and traces out the magnetic field on the Sun.

Movement of Plasma The plasma is trapped within the magnetic fields. It can flow lengthwise along the loops, but it cannot flow sideways across the loops.

Suns magnetic fields The magnetic fields in sunspots do not allow plasma from the surrounding region to enter which results in a drop in plasma pressure and cooler temps. ***The magnetic field strength in a Sunspot is an average of 1,000 times stronger than the magnetic field at Earth’s surface.

The solar cycle Because the equator of the sun moves faster than the poles, the sun’s magnetic field becomes more and more twisted and complex. It finally breaks and flips every 11 years. As the magnetic field becomes more twisted small loops of it push through the surface creating sunspots and coronal loops

Solar Flares Solar flares occur when gases emitted by sunspots reach an excited state (moving as fast as the speed of light) causing them to give of ultraviolet and x-ray radiation -They contain so much energy that the sun’s magnetic fields cannot hold them and they are released into space

Solar Flares Continued -Large solar flares can emit large bubbles of plasma called coronal mass ejections (CME’s) -Coronal mass ejections can change the solar wind and create colorful ribbons of light called auroras -Strong CME’s can create solar storms that can even affect the magnetic poles of earth https://www.youtube.com/watch?v=F8hStTFQHq8 https://www.youtube.com/watch?v=KL6wi3QjXjk https://www.youtube.com/watch?v=jnnSIwIUzVE

Read the article and answer the questions 1. In your own words explain why the sky is blue. (3-5 complete sentences) 2. Explain why the sunsets are often red. http://www.sciencemadesimple.com/sky_blue.html

Sun= Energy The sun is earth’s main energy source Half of sun’s energy is absorbed by earth’s surface Other half absorbed by atmosphere reflected back into space by earth or clouds

Why is the sky blue? Scattering- dust and gas in earth’s atmosphere deflect radiation from the sun - atmosphere scatters shorter wavelengths of light in the blue range more strongly than longer wavelengths.

Earth’s Atmosphere -Made mostly of nitrogen (78%) -Oxygen (21%) -Other gases (1%) Oxygen and Nitrogen absorb very little sunlight

Absorbing Sunlight Surface of earth and oceans absorb energy from sun and warm up. Air above surfaces warms and rises Cool air sinks down Energy that is radiated from earth’s surface is in the form of infrared radiation

Albedo Reflectivity- measured as a percentage of radiation that is reflected Earth’s albedo including it’s atmosphere is .3 30% of energy from the sun is reflected Most of the energy is reflected by clouds and air 4% reflected by earth’s surface Different surfaces have different albedos

Benefits of Solar Radiation Required for photosynthesis- process in which plants make their own food Animals feed on plants or one another Creates weather Drives movement of oceans Powers water cycle Provides earth’s energy- solar power, wind power, formation of fossil fuels

Harmful Solar Radiation UV rays can cause tissue damage to both humans and plants UV rays are increasing due to depletion of ozone layer Ozone- 3 oxygen atoms combined CFC’s or chlorofluorocarbons are pollutants released from different chemicals on earth CFC’s bond with oxygen from O3 breaking apart the ozone molecules Less ozone in the ozone layer=more UV rays reaching earth

ABC’s left page assignment Using your notes on the sun you must come up with a term for each letter of the alphabet and give a definition or explanation of how it relates to class. You are allowed 3 skips. Example: A- Albedo- another term for reflectivity, earth’s albedo is 30% meaning 30% of energy from the sun is reflected