2The Earth as a SystemOur Earth is made up of rock, air, water and living organisms.Rock = GeosphereAir = AtmosphereWater = HydrosphereLiving organisms = Biosphere
3The GeosphereEarth is composed of rock – both solid and molten – as well as various metallic elements.This solid part of the Earth, as well as the soil and loose rock on the exterior, makes up the geosphere.
4The GeosphereThe Earth’s geosphere is divided into three chemical sections:The crust, composed almost entirely of light elements, like silicon.The mantle, which is 68% of the Earth’s mass.The core, the innermost layer; it is composed of very dense elements, such as nickel and iron.
5The Crust The crust makes up less than 1% of the Earth’s mass. There are two types of crust:Continental crust, and oceanic crust.
6The Crust Continental crust is about 30-35 km thick. It is also made up of lightweight and low density materials.
7The Crust Oceanic crust is much thinner – it’s only about 5 km thick! It is also made up of heavier and denser materials.
8The Mantle The mantle is about 2900 km thick. It is made up of dense materials, which are rich in iron.The mantle is semifluid; the molten rock flows very slowly, which lets the solid plates move on top.Much like cereal flows on top of syrup!
9The Core The outer core is composed of dense liquid metallic elements. Mainly nickel and iron.The inner core is composed of solid nickel and iron.This is due to the immense pressure found at the center of the Earth.Outer CoreInner Core
10Exit TicketThe Earth’s solid elements (soil, earth and rock) are collectively called the __________.The geosphere has three chemical layers. List them.___________ crust is about 5 km thick, and is made of relatively dense materials.Why is the inner core solid?
11Structure of the EarthThe Earth can also be divided into five layers, based on its physical properties.They are:Lithosphere – rigid and solid earthAsthenosphere – plastic; made of molten rockMesosphere – Lower mantle, transitions to the liquid outer coreOuter Core – made of dense, molten iron and nickelInner Core – made of solid iron and nickel
12The Lithosphere The lithosphere is cool, solid and rigid. It is divided into many smaller pieces called tectonic plates.
13The Asthenosphere The asthenosphere is semi-fluid, molten rock. This allows the tectonic plates to move on top.This motion is essential to our Earth‘s appearance.
14Plate TectonicsAs discussed earlier, our crust is divided into smaller tectonic plates.These plates glide on the surface of the upper mantle.The movement of these plates can have far-reaching effects on us.
16Plate TectonicsA great deal of Earth’s tectonic activity takes place at the boundaries of the tectonic plates.Tectonic activity deals with activity that affects Earth’s surface.Enormous forces are at work whenever the tectonic plates collide, pull apart, or slip beside each other.
17Plate TectonicsWhen the plates collide with each other, earth is pressed upward and folds.This leads to the creation of mountain ranges.
18Plate TectonicsWhen plates slide past each other, faults – breaks in the Earth’s crust – sometimes appear.The intense forces involved when this happens cause earthquakes.Most earthquakes are so minor that we can’t feel them.
19Plate TectonicsThe magnitude of an earthquake is the energy that is released.We use the Richter scale or the more modern moment magnitude scale (MMS) to measure this energy.The lowest magnitude that can be detected is about 2.0. The greatest magnitude that has ever been recorded is 9.5.Earthquakes that cause widespread damage typically have a magnitude of 7.0 and up.
20Plate Tectonics Earthquakes can cause damage in various ways: Pressure (P) and shear (S) waves cause vibrational motion. P-waves cause up-and-down motion, and S-waves cause side-to-side motion.S-waves are much more dangerous.Earthquakes can cause tsunamis, or large tidal waves, if the originate in ocean areas.Earthquakes can liquify sandy areas, causing buildings and other structures to sink into the ground.
21Exit TicketWhat layer of the Earth contains the tectonic plates? (2 possible answers)Why can Earth’s tectonic plates move?Most tectonic activity occurs along Earth’s _____________________.Mountain ranges are formed when tectonic plates _________________.Is it possible to never notice an earthquake?Describe one way than an earthquake can cause damage.
22Volcanic ActivityVolcanoes are, in essence, large vents for molten rock to rise to the surface.We call this molten rock magma while it is underground, and lava once it is above ground.
23Volcanic ActivityVolcanic vents often form when plates move apart from each other.This can happen on the surface or underwater.Some vents appear due to weak points in the crust, called hot spots.
24Volcanic ActivityVolcanic eruptions occur when magma is trapped underground, and the pressure builds up to critical levels.Some volcanoes do NOT erupt, as magma is not trapped, and can flow freely.
25Volcanic ActivityVolcanic eruptions can have devastating effects on the Earth’s surface.Ash, dust and rock can bury building, crops and organisms.Ash can mix with water to form dangerous mudflows.Ash and dust can disrupt engines and breathing.Ash and sulfurous gases can reach the upper atmosphere. Here, they block sunlight, which reduces the average global surface temperature.
26Weathering and Erosion Weathering is the process of breaking rock down into smaller pieces.Erosion is the process of moving the broken rock and loose dirt elsewhere.There are many forces that cause weathering and erosion:WindWater and mudflowsPlant lifeHuman activity
27Exit Ticket Volcanoes are primarily ___________________. What are hot spots?Why do some volcanoes NOT erupt?Describe one way that a volcano can cause damage.List one means of weathering and erosion on Earth.