Round from pull of gravity over time Size & Shape About 24,000 miles around Radius 6400 km Round from pull of gravity over time Any object larger than 700 km will become a circle

Composition Crust: ____ & ______ Mantle: _______ (Magnesium, Iron, Silicon) Liquid Core & Solid Core _____________

Separation of materials by density is Seismic Waves (_________) How can we tell? Density Separation of materials by density is Seismic Waves (_________)

P waves __________ travel in _____________ S waves _______waves only travel through _________

Heat 2 theories Earth began hot and attracted more mass and gained heat from the ________ Generated heat from _______________

Age of Earth 4.5 billion years

_________- heated matter expands and rise Heat causes motion _________- heated matter expands and rise ________ – stretching and spreading of crust _________- one plate slides under another

1912 ________________________ Alfred Wegener 1912 ________________________ __________________ All continents began together Evidence: ______________

2 theories ________ collisions ________ explosions Atmosphere 2 theories ________ collisions ________ explosions

Atmosphere protection _______ (O3) block UV radiation ________- trapped heat from the Sun

__________ Effect from currents in molten core protects us from charged particles from the Sun ________- belts of trapped radiation

Coriolis Effect/ Magnetism