Layers of the Earth and Convection

Layers of the Earth and Convection

3.1 Spring 2012

Do Now!

1) Describe and draw out the layers of a pizza slice starting with the outside edge.

2) What do you think causes a hot air balloon to rise?

Agenda

• Do Now• Intro to Unit 3 + BIG GOALS• Foldable-A Slice of Earth• Convection Demos & Video Clips• Guided Notes: Earth Layers & Convection• Exploration Exercise• Exit Ticket

FAST FACT for the College-bound!

• If one student has high grades but low test scores and another has low grades but high test cores, the first student is far more likely to get accepted into a better college. Colleges prefer the “bad test-taker” to students who don’t apply themselves.

Objective

• SWBAT identify the layers of the Earth and explain the various mechanisms that drive movement of lithospheric plates (2.02)

BIG MYSTERY!!!• HOW DID WE GO FROM THIS…..

BIG MYSTERY!!!

• TO THIS….

LET’S PIECE TOGETHER THE MYSTERY….

• Beginning with the layers of the Earth

Inner Core1200 km = 745 miles Miami to Charlotte

Outer Core2250km = 1398 miles Miami to NYC

Mantle2900 km = 1802 miles Miami to the tip of maine

Crust31.15 km = 19.36 miles Carowinds to UNCC

Crust

Mantle

Outer Core

Inner Core

Slice of Earth Foldable-20min1. Cut out layers and glue onto the outside

layers of your foldable2. Label the layers-use the list provided3. Using pg. 233-237 in your textbook, write out

the composition, thickness, & state of matter (solid, liquid, gas) on the inside layers

4. If you finish early, you may color the different layers and include more detail from your textbook/notes

*You are in your seat and on-task!!

Layers of the Earth-15min• Pizza-Making Pairs• Step 1: Select jobs: measurer, drawer, labeler, outliner• Step 2 : Refer to table of measurements on left side of

handout (you will use the cm side of the ruler)• Step 3: Draw your first line (63.7 cm) down the middle of your

paper & draw the outline of your ‘slice of Earth’• Step 4: Measure out the individual layers (start with inner and

outer core; measure from the point of your slice)• Step 5: Label and outline the different layers• Include all names on your activity!!

Critical Thinking

What makes hot air balloons rise??

Density

Which box is more dense?

Now, which is more dense?

So, what exactly is density?

Density is the mass per unit volume

In other words…– The number of particles in a certain amount of

space

Class Demo

• The boxes on the floor are the same volume, or the same amount of space

• Volunteers– How many are in each box? Which is more dense?

Where would you want to be?Cold vs. hot

Same goes for particles

When something is cold, its particles are closer together. This means that it will be more dense. If something is warm, its particles are farther apart. This means it will be less dense.

Karo Syrup: Take 2

PREDICT: Which will be more dense, the karo syrup on the hot plate, or the karo syrup from the refrigerator? Why?

What happened to the cold karo syrup when it was added to the warm karo syrup?

Why do you think that happened?

So what does that mean?• The cold Karo syrup was more dense then the warm karo

syrup. The cold karo syrup sunk to the bottom when it was added to the warm karo syrup. The warm karo syrup rose to the top when the cold syrup was added.

• This tells us that things that are more dense sink and things that are less dense rise.

• Because the bottom of the mantle is heated up, it is less dense than the mantle above it

• Since it is less dense, it rises towards the top of the mantle. As it reaches the top of the mantle it cools and becomes more dense. As it becomes more dense, it will start to sink.

DENSITY & TEMPERATURE DEMO

• http://www.youtube.com/watch?v=7xWWowXtuvA (two colors)

Check for understanding!

• In what layer are the plates?

• In what layer does convection occur?

1) The core of the earth does not heat the mantle directly. As the outer core warms up certain parts of mantle, the magma becomes less dense.

2) Since it is less dense, it rises. As it rises, it moves the lithosphere horizontally (“slab pull”)

3) Eventually, this magma cools off and becomes more dense and sinks.

4) This process of heated magma rising and then cooling and sinking, is called convection.

• Make sure your drawing above has arrows drawn to show the rising and falling magma. Label these arrows CONVECTION.

How does this relate to Earth Science?• Scientists generally agree that convection occurring in the mantle is the basic

driving force for plate movements • During convection, warm, less dense material rises and cooler, denser material

sinks• The slow movements of the plates and mantle are driven by the unequal

distribution of Earth’s heat• The core is the heat source for the thermal convection taking place in the mantle.• The unequal distribution of heat within the Earth causes thermal convection in

the mantle that ultimately drives plate motion

Material Density in g/cc Material Density in g/cc

Steel 7.8 Water 1.0Lead 11.3 Brass 8.4

Aluminum 2.7 Balsa Wood .16Oil .9 Wood (fir) .45

Gold 19.3 Mercury 13.6Cork .2 Gasoline .75Ice .99 Wood (oak) .8

Zinc 7.1 Platinum 21.4

A little bit more…

• The lithospheric plates move relative to each other at a very slow but continuous rate that averages about 5 centimeters per year – about as fast as your fingernails grow!

• The movement of the plates is driven by unequal distribution of heat within the Earth

• Hot material found deep in the mantle moves slowly upward as part of the earths internal convection system

• At the same time, cooler denser slabs of oceanic lithosphere descend into the mantle, setting the earths rigid outer shell into motion

Critical Thinking

So…can you explain it??

Pulling it all together-convection Video Clip

• http://www.youtube.com/watch?v=ryrXAGY1dmE

• Article Analysis

Exit Ticket

1. What is convection?2. Where does convection take place in the

earth?3. What is the heat source for the convection?4. How does convection relate to how the

plates move?5. How much do lithospheric plates move each

year?