DISCOVERY: PLANET EARTH…

DISCOVERY UNIT: Topics to be Discussed Discovery of the Earth Composition of Earth and Atmosphere Layers of our Atmosphere Volcano’s Rock cycle Earthquakes Erosion Tsunami Moon phases and orbits Tides – moon Our Place in the solar system the Suns impact Day and night Seasons

MIND MAP-PLANET EARTH

First Glimpse of Planet Earth:

Flat or Round??? What do you think? Until the sixteenth century, most people thought the earth was flat, and there was plenty of evidence to support this belief. Many sailing ships did not return from long journeys and it was assumed that they fell over the edge of the earth. http://www.youtube.com/watch?v=GbizzLzcpnM

Round… Despite considerable ridicule, Ferdinand Magellan sailed west from Spain in 1519 towards what is now Indonesia. While he died on the trip, one of his ships, the Victoria, continued on and ended up being the first ship to circumnavigate the world. This journey provided strong evidence that the world was round.

Formation of the Atmosphere: Narrow band of air maintains the correct temperature that allows life to form and survive.

Composition of Atmosphere:

Structure of Our Earth:

Structure of our Earth: Earth is over 1200 km thick and has four distinct layers. These layers are the i) crust ii) mantle (upper and lower) iii) outer core iv) and inner core. 1) Crust – outer solid rock layer (all landforms, rocks, soil) Two types i) Contentinental ii) Oceanic Lithosphere-outer soild part of Earth; 100 km thick; very brittle; earthquakes can occur Athenosphere-an area located beneath the lithosphere and is part of the mantle; responsible for movement (convection currents) of plates 2) Mantle – thickest layer, Upper Mantle-solid Lower Mantle- liquid; flows like “thick toothpaste” -2900 km thick -temp from 500 C – 2200 C 3) Outer core – composed of liquid iron and nickel -2300 km thick -temp 4000 C – 6000 C 4) Inner core – mostly solid iron, at tremendous temperature and pressure -1200 km thick --temp 7000 C

Layers of the Atmosphere:

Layers of our Atmosphere 1) Troposphere - - region where all plants and animals live and breathe, weather takes place here; highest density layer (8-16km) 2) Stratosphere- -exists only on planets with life, creates oxygen (16-50km) -air is cold and clean -planes fly here -Ozone layer; blocks ultraviolet (UV) light that generates the heat that warms this layer. 3) Mesosphere - very cold, see “falling stars”, “meteors” burning through the atmosphere; (50-90km) -temperatures of -90C to -100C. 4) Thermosphere - outermost layer of the Earth’s atmosphere, very hot (temperature increase with altitude); aurora borealis (90-500km) 5) Exosphere- the highest but thinnest part of the atmosphere (500-700km) Ionosphere- atoms and molecules, layer of ions bend long wavelength of electromagnetic waves used in radio transmissions;

Make your own atmosphere: Materials: -ruler/colored pencils Using A4 paper, -Divide your paper into 5 sections -label each layer by its name and appropriate distance -describe and draw what you see in each layer TOTAL: 10 marks -1 mark drawing -0.5 distance of layer -0.5 mark for name of layer