Getting to know our Earth

Introduction

Let’s find out more about our Earth by looking at: The Four Main Regions of

the Earth How seismic waves tell us

about Earth’s interior What it means to say the

Earth is differentiated The Theory of Tectonics Earths Atmosphere

Sometimes people may forget or take for granted how lucky we are that Earth is so suitable for human life.

Four Main Regions of the Earth

Crust

Mantle

Outer Core

Inner Core

Interior of the Earth

Core- consists of a solid inner core

and a liquid molten outer core.

Mantle- Rocky material containing

the minerals silicone and oxygen

Crust- Continental crust is made

mostly of granite while Ocean

crust is made of basalt.

The lowest density rock is found at the crust while the highest density is found at the core

Seismic Waves

Seismic waves are waves of energy that pass through the Earth as a result of an Earthquake for example.

P waves (primary waves) travel fastest and are produced first by an earthquake. P waves can travel through liquid and solid material.

S waves (secondary waves) follow and do not travel through liquid.

Application

Scientists can use seismographs to record seismic waves and learn about the interior of Earth.

After a volcano at some point the waves hit the outer core and because the outer core is liquid only the p waves can travel through and the s waves are stuck.

Differentiation

The Earth is made up of layers of different materials. This is due to differentiation.

The Earth was once hot enough inside that it caused the interior to melt so that materials of higher density sank to the center and less dense materials went towards the surface.

How did the Earth become so hot?

Two major reasons explain the Earths heat. 1. Planets were hot

because of the process of formation. Colliding planetestimals deposited large amounts of energy that turned into heat.

2. The metal and rock that make up the Earth contain radioactive elements that when decaying produce heat.

Plate Tectonics

Earths rocky outer crust is not solid but instead broken up into huge plates that sit on top of the mantle.

The theory of plate tectonics explains the movement of Earths plates and the reason why we have earthquakes, volcanoes, mountains, trenches and many other geological features.

Plate Tectonics Continued… At the boundaries of plates they may

separate from one another, collide, slip past one another, and slip laterally.

Processes that shape Earths Surface

Impact Cratering

Volcanism

Tectonics

Erosion

Troposphere

We live in the troposphere which is the lowest layer of Earth’s atmosphere.

Earths Atmosphere

Earths Atmosphere today consists of: 78% nitrogen (N2) 21% oxygen (O2) Small amounts of

other gasesOur atmosphere

provides the air we breathe and the pressure that allows liquid water to flow

Earth’s Early Atmosphere

Earth’s original atmosphere consisted of volatile gases such as Carbon dioxide, Water Vapor, Methane, and Ammonia.

How then did we come to have the atmosphere that allows human life now?

Earth’s Changing Atmosphere When the Earth had cooled

the water vapor had condensed and formed our oceans.

Photosynthesis reduced the carbon dioxide level and increased oxygen that is necessary for all life.

Carbon dioxide was also trapped inside rocks

Volcanic eruptions released nitrogen into the air through a process called outgassing.

Conclusion

Our Earth is a complex planet that has grown and evolved since its formation millions of years ago.

Next week we will compare Earth to other planets in order to understand further what makes it so unique.

SourcesSlide 1

Picture: http://www.google.com/imgres?imgurl=http://img.dailymail.co.uk/i/pix/2007/07_03/nasa1R3107_1000x1000.jpg&imgrefurl=http://www.dailymail.co.uk/news/article-472122/Most-detailed-pictures-Earth-seen.html&h=1000&w=1000&sz=221&tbnid=XsopFnti7RPgrM:&tbnh=103&tbnw=103&prev=/search%3Fq%3Dpictures%2Bof%2Bthe%2Bearth%26tbm%3Disch%26tbo%3Du&zoom=1&q=pictures+of+the+earth&docid=O1b5XpbTR7sSYM&hl=en&sa=X&ei=NOaUTpvpMoLciAKUmqGMBQ&sqi=2&ved=0CDsQ9QEwAA

Slide 2 Picture:http://www.google.com/imgres?q=information+about+earth&um=1&hl=en&biw=1280&bih=570&tbm=isch&tbnid=QVPwqS25lFIJEM:&imgrefurl=http://theawesomefacts.blogspot.com/2011/04/awesome-facts-about-earth-you-may-newer.html&docid=EP4G_28bZpYejM&w=576&h=228&ei=1vaUToLRNMniiAK9h4mlBQ&zoom=1&iact=rc&dur=44&page=8&tbnh=88&tbnw=223&start=83&ndsp=10&ved=1t:429,r:2,s:83&tx=52&ty=68

Slide 3Picture: http://www.physicalgeography.net/fundamentals/10h.html

Slide 4Text:

http://library.thinkquest.org/12232/data/TheEarthsInterior.htmlBennett/ Donahue/ Schneider/Voit’s The Essential Cosmic Perspective. Sixth Edition. pages 192-193

Slide 5Text:

http://en.wikipedia.org/wiki/Seismic_wave

Sources ContinuedSlide 6:Picture:

http://www.kcvs.ca/martin/astro/au/unit7/172/chp17_2.htmlText:

Bennett/ Donahue/ Schneider/Voit’s The Essential Cosmic Perspective. Sixth Edition. page 195Slide 7:Picture:

http://www.indiana.edu/~geol105/images/gaia_chapter_3/earth_differentiation.htmText:Bennett/ Donahue/ Schneider/Voit’s The Essential Cosmic Perspective. Sixth Edition. Page 194

Slide 8:Picture:

http://www.google.com/imgres?q=earths+temperatures&um=1&hl=en&biw=1280&bih=570&tbm=isch&tbnid=7rsby46eNIROaM:&imgrefurl=http://www.scarborough.k12.me.us/wis/teachers/dtewhey/webquest/nature/plate_tectonics.htm&docid=AU2OtRwIg64RXM&w=507&h=388&ei=df2UTqLXEa2rsALNsMzvAQ&zoom=1&iact=hc&vpx=186&vpy=170&dur=112&hovh=196&hovw=257&tx=165&ty=131&page=1&tbnh=147&tbnw=192&start=0&ndsp=10&ved=1t:429,r:5,s:0

Text: Bennett/ Donahue/ Schneider/Voit’s The Essential Cosmic Perspective. Sixth Edition. Page 194

Slide 9:Text:

http://www.enchantedlearning.com/subjects/astronomy/planets/earth/Continents.shtmlSlide 10:Text and Picture:

http://www.enchantedlearning.com/subjects/astronomy/planets/earth/Continents.shtmlText:

Bennett/ Donahue/ Schneider/Voit’s The Essential Cosmic Perspective. Sixth Edition. Page 199

Sources ContinuedSlide 11:Pictures:Erosion:

http://www.google.com/search?hl=en&cp=12&gs_id=12&xhr=t&q=tectonics+plates&qe=dGVjdG9uaWNzIHBs&qesig=u8up7J7wF_ImuT1MSJxwHA&pkc=AFgZ2tlo8xdWexearn9yWLvwNhqpTjx3503MBIWTVlk3K2b6ChQTeVXhGqz397NwDX6oRV42ss5HDf2sbOR78_osiCqa5qhqLQ&gs_sm=&gs_upl=&bav=on.2,or.r_gc.r_pw.,cf.osb&biw=1280&bih=570&wrapid=tljp1318389175936018&um=1&ie=UTF-8&tbm=isch&source=og&sa=N&tab=wi#um=1&hl=en&tbm=isch&sa=1&q=erosion&oq=erosion&aq=f&aqi=g10&aql=&gs_sm=e&gs_upl=2607l5321l0l5696l20l9l0l0l0l3l402l1164l4.3.4-1l9l0&bav=on.2,or.r_gc.r_pw.,cf.osb&fp=62195ff4a89d15b&biw=1280&bih=570

Tectonic Plates:http://www.google.com/imgres?q=tectonics+plates&um=1&hl=en&sa=N&biw=1280&bih=570&tbm=isch&tbnid=b0d3cTrRmLy7WM:&imgrefurl=http://www.moorlandschool.co.uk/earth/tectonic.htm&docid=vh71KLxugM92lM&w=429&h=254&ei=bQaVTs6qAvKpsALZkJnvAQ&zoo

Volcanoes:http://www.google.com/search?hl=en&q=volcanism&gs_sm=e&gs_upl=3437l6657l0l6861l21l12l0l0l0l1l290l2358l0.3.7l11l0&bav=on.2,or.r_gc.r_pw.,cf.osb&biw=1280&bih=570&wrapid=tlif131838941166910&um=1&ie=UTF-8&tbm=isch&source=og&sa=N&tab=wi

Impact Cratering:http://www.google.com/search?hl=en&q=volcanism&gs_sm=e&gs_upl=3437l6657l0l6861l21l12l0l0l0l1l290l2358l0.3.7l11l0&bav=on.2,or.r_gc.r_pw.,cf.osb&biw=1280&bih=570&wrapid=tlif131838941166910&um=1&ie=UTF-8&tbm=isch&source=og&sa=N&tab=wi#um=1&hl=en&tbm=isch&sa=1&q=impact+cratering&oq=impact+cratering&aq=f&aqi=g1g-S3g-mS2&aql=&gs_sm=e&gs_upl=49860l54965l0l55263l20l14l1l1l1l0l237l1462l4.6.1l11l0&bav=on.2,or.r_gc.r_pw.,cf.osb&fp=62195ff4a89d15b&biw=1280&bih=570

Text: Bennett/ Donahue/ Schneider/Voit’s The Essential Cosmic Perspective. Sixth Edition. Page 197

Sources Finale

Slide 12:Picture:

http://www.google.com/search?hl=en&cp=7&gs_id=k&xhr=t&q=earths+layers+of+atmosphere&qe=ZWFydGhzIA&qesig=jZln4vNkirtn-pRWyJwWFA&pkc=AFgZ2tmYp_QwmVeG3aiulbjkIVzixtIUxWtNto3-21HHSoRmJyYTADFt6ArcM8gBF29LL_158_LcC9ec1o4u8-ntd2xfy7yDQA&gs_sm=&gs_upl=&bav=on.2,or.r_gc.r_pw.,cf.osb&biw=1280&bih=570&wrapid=tljp1318439904501012&um=1&ie=UTF-8&tbm=isch&source=og&sa=N&tab=wi

Text: http://www.windows2universe.org/earth/Atmosphere/troposphere.html

Slide 13:Picture:

http://www.123rf.com/photo_10245620_air-composition-pie-chart.htmlText:

Bennett/ Donahue/ Schneider/Voit’s The Essential Cosmic Perspective. Sixth Edition. Page 200Slide 14:Text:

http://www.globalchange.umich.edu/globalchange1/current/lectures/Perry_Samson_lectures/evolution_atm/index.html

Slide 15:Picture:

http://www.globalchange.umich.edu/gctext/Inquiries/Inquiries_by_Unit/Unit_8.htmText:

http://en.wikipedia.org/wiki/Earth%27s_atmosphere Bennett/ Donahue/ Schneider/Voit’s The Essential Cosmic Perspective. Sixth Edition. Page 198