Grab you ISN Take out Last night’s HW: Fossils Article. VOICE LEVEL 0 Table of Contents Pg Date Title Type 16 9-19 EQ/ I Can/T-Chart Notes 17 9-19 Absolute vs. Relative Age Notes 18 9-19 Absolute vs. Relative Age Notes 19 9-19 Absolute vs Relative Age Notes 20 9-19 Absolute vs relative Age notes 21 9-19 Absolute vs relative age notes 22 9-19 Reading Rock Layers Notes 23 9-19 Finding Clues to Rock Layers worksheet 24 9-19 Exit Ticket Notes 25 blank did not use blank

Write the following on Pg 16 of ISN EQ: How can you determine the changes in time based on Geologic events? I Can: differentiate between relative and absolute dating.

Earth’s History

Student Objectives By the end of this lesson students will be able to…. Identify the difference between absolute and relative age Determine the relative age of a rock using the law of superposition and index fossils Explain how ice cores help scientists study how Earth’s climate was in the past

Vocabulary Relative Age Absolute Age Law of Superposition Igneous Inclusion Index Fossil Unconformity

SOOO….. Warm Up (Verbal) Looking at our list of vocabulary words, which do you think means exact? Which of our vocabulary words do you think means estimate? Relative Age Absolute Age Law of Superposition Igneous Inclusion Index Fossil Unconformity

Relative Age Absolute Age Absolute vs. Relative Age (Draw a T Chart on page 16 of ISN (under the I Can) Relative Age Determining the age of an object in relation to other objects “Estimate” Index Fossils, Rock layers Example: A friend tells you she has 2 brothers – one that’s older than her and one that’s younger Absolute Age Determining the actual age in years of an object “Exact” Radiometric dating, half life, radioactive decay Example: I have one brother who is 8 years old and one who is 17 years old

Mnemonic Memory Help- Write on pg 17 of ISN When you hear these two terms, think… Absolute = exact Relative = estimate

How old is old? Write on Pg 17 of ISN Scientists use several strategies to determine age of rocks and fossils. Absolute Age: actual age of an object or how long ago an event occurred by using radioactive dating. Radioactive Dating: measures age by comparing the amount of radioactive element isotope present to how much is normally present in that material Relative Age: age of an object compared to another- “I am older than you”

So… Why Do We Care?- Write on pg 17 of ISN Relative and Absolute Dating tell us… The age of the Earth as well as its history When the dinosaurs roamed the earth How the Earth was and where it is going Possibly Skip this slide? Need Transition

Which layer do you think is the oldest and youngest? Law of Superposition Says: “ The rocks at the bottom are OLDER than the rocks above”

The Position of Rock Layers Write on Pg 18 of ISN It can be difficult to determine a rocks absolute age. So… scientists use the law of superposition. According to the law of superposition, in horizontal sedimentary rock layers the oldest layer is at the bottom. Each higher layer is younger than the layers below it.

Cornell Notes- Write on pg 18 of ISN In an undisturbed rock layer, the layer of rock on the bottom is OLDER than the layers above it. Makes Sense: Older sediments must be laid down before the younger ones can pile up on top What is the Law of Superposition?

Let’s Practice Together! Which rock layer is the oldest? Which rock layer is the youngest? Which is older, layer M or layer R? How do you know Put them in order from oldest to youngest Which is younger R or T? How do you know?

Relative Age Clues - write on page 19 of ISN Clues from Igneous Rocks: 1. Lava that hardens on the surface is called an Extrusion (example – an eruption would put a layer of igneous rock on top of sedimentary rocks. Rock layers below an extrusion are always older than the extrusion.

The extrusion is in black

Now the extrusion is the youngest layer.

Write on page 20 of ISN 2. Magma that cools and pushes into bodies of rock and hardens is called an Intrusion An intrusion is always younger than the rock layers around and beneath it.

Draw on page 20 of ISN The intrusion (in red) is now younger than the surrounding rocks.

Draw and label on page 20 of ISN

Clues from Faults: write on page 21 of ISN Fault: a break in the Earth’s crust. Forces inside the Earth cause movement of the rock on opposite sides of a fault. Fault is always younger than the rock it cuts through. Unconformities: gap in the geological record that can occur when erosion wears away rock layers and other rock layers form on top of the eroded surface. Movements along faults can make it harder for geologists to determine the relative ages of rock layers. (book figure 10 B)

Other Clues to Relative Age Fault Unconformities

Draw on page 21 of ISN

Think. Write the question. Pair Think*Write the question*Pair*Share ( Write on pg 21 of ISN) Is dating rocks using the law of superposition a form of relative dating or absolute dating? Explain your answer

Remember… Law of Superposition is a form of relative dating Relative dating is based on the rocks that are surrounding it, NOT the exact age We know which is older but we do not know HOW old exactly

Now we are going to Practice in Pairs Finding Clues to Rock Layers Skills Lab. Cut and Glue Rules for Reading The Layers on pg 22 of ISN

Which rock is younger, limestone or basalt? How do you know? TICKET OUT! Draw and label diagram on pg 24 of ISN. Write and answer the questins Which rock is younger, limestone or basalt? How do you know? Which of the labeled rocks is oldest? How do you know? Which of the labeled rocks is youngest? How do you know? Name the rocks in order from oldest to youngest.

Grab you ISN VOICE LEVEL 0 Table of Contents Pg Date Title Type 26 9-26 EQ/ I Can/ diagram Notes 27 9-26 index fossils/ Ice core Notes 28 9-26 Ice Core Notes Notes 29 9-26 Ice Core Notes Notes 30 9-26 Law of Superposition Map Notes 31 9-26 Relative Dating Activity Notes EQ: How can you determine the changes in time based on Geologic events? I can demonstrate my understanding of Ice core fossils and how they are used in science.

Do Now Draw, label and write on page 26 of ISN. What is the Law of Superposition? Which rock layer is the OLDEST? How do you know? Which rock layer is the YOUNGEST? How do you know

Using Fossils to Date Rocks! Read but don’t write. Scientists use index fossils to match rock layers. An index fossil must be widely distributed and represent a type of organism that existed only briefly. They are useful because they tell the relative ages of the rock layers they are found in.

Fossils give us clues about. . . Read but don’t write. How old a rock is. What life existed in the past. When big events happened. Climate in the past.

Index Fossils (write on page 27 of ISN) Organisms that lived during a specific time IDENTIFY THE AGE OF ROCK THEY ARE FOUND IN INDEX FOSSILS MUST BE WIDE SPREAD They also help compare ages of rocks layers around the world

Fossils and Climate (write on page 27) Climate=average conditions like temperature, humidity, wind, and rainfall. Fossils show us how climate changes over time.

Today we will be talking about ICE CORES and what they can tell us about Earth’s past

Ice Cores (write on page 27 of ISN) Ice forms layers similar to that of rock (follow law of superposition). Contain elements that help describe climate of Earth Scientists drill down and pull ice cores up An ice core from Antarctica 3km long showed 740,000 years of history and 8 ice ages!!!

Write the information that is in red on page 28 of ISN. Ice Cores I. Climate and Ice Video Show All (Total Time 5:26) http://www.youtube.com/watch?v=v5BrOLkRgRI&feature=relmfu http://www.teachertube.com/video/climate-and-ice-240110 What do glaciers record? 3 other facts

Only show Time 0:00 to 6:42 Write the information in red on pg 28 of ISN. 2. Recovering Ice Cores Video http://www.youtube.com/watch?v=Fssy7FWTpMA http://www.teachertube.com/video/recovering-ice-cores-240111 What is an Ice Core? 3 other facts

What do ice cores reveal about climate change in the past and future? Show all (Total Time 4:25) Write the information in red on pg 29 of ISN. 3. Predictions in Ice Video http://www.youtube.com/watch?v=6BEMeA9rVL8&feature=relmfu http://www.teachertube.com/video/predictions-from-the-ice-240121 What do ice cores reveal about climate change in the past and future? 3 other facts

Set Up Your Notes First! (write) What is an igneous inclusion? What is an ice core? Definition 2 Facts Picture

Set Up Your Notes First! (write) What is an index fossil? What is an unconformity? Definition 2 Facts Picture

EOG PRACTICE Which statement BEST explains why Greenland, which is ice-covered and located in the Arctic region, has fossils of tropical plants? Greenland was once located in the tropics and had a tropical climate. Birds carried plant seeds from the tropics to Greenland. Plants used to be adapted to grow in ice-covered regions. Ocean currents carried the fossils to Greenland.

Reading about Earth’s History You are now going to read an article called “Dating the Earth: Rocks, Fossils, and Ice Cores” This tells you key points the EOG always ask its 8th graders As you read you will be required to take notes cornelle style This information will be on your independent practice as well as the assessment….SO DO A GOOD JOB!