Earth’s Age + Evidence

WARM UP• Update your Table of Contents for today’s

activities• Get your data folder off the front desk• Complete Types of Rock Review section

at the top of your note guide

Date Session#

Activity Page#

9/13 7 Earth’s Age & Evidence Note guide 14

Law of Superposition Practice 15

Review: Types of Rock

Which one?

- Created from the deposition of loose material accumulating into layers and being pressed together over time

Review: Types of Rock

Which one?

-The result of the transformation of other rocks into a new form

Review: Types of Rock

Which one?

- Created when molten rock (magma) cools and hardens

Notes Tips and Tricks

• Anything in yellow you MUST write on your note guide

• Pictures and diagrams are great things to also draw to help you remember vocab and ideas!

• Underlined or bold words that are underlined or bold in PowerPoint BECAUSE THEY ARE IMPORTANT!

How old is the Earth?

Earth is around 4.6 BILLION years old.

BIG QUESTION:

HOW DO WE KNOW HOW OLD THE

EARTH IS?

BIG ANSWER:

Everything coming up provides an

answer to the BIG QUESTION!

Law of Superposition

• Law of Superposition– •Under normal conditions, the layers of sediment get older the deeper you get

Examples of Law of Superposition

• Just like a layered cake…you put the bottom layer down first,

so it is the “oldest” and

you fill in each layer on

top of it! What examples

can you come up with?

Draw your own picture

illustrate the concept!

We Have a Problem…

• There are several things can mess up the Law of Superposition called unconformities

Types of unconformities:

1 – intrusion

2 – overturning

3 - faults

Unconformity• Unconformity-

•A break or an irregularity in the geologic time sequence due to a geologic event.

•“Missing Information”

1. Intrusion• A intrusion is igneous rock that cuts

through layers of sedimentary rock. The intrusion is younger than any other rock layer it cuts through.

intrusion

2. Overturning• Overturning is when rock layers

are folded due to gravity, erosion, or shifts in Earth’s crust

3. Faults• Faults are cracks, fractures or shifts in

Earth’s crust

Fault

Law of Superposition Practice

Which type of unconformity do you see in the diagram?

Can you put the layers in order from oldest to youngest?

Law of Superposition Practice

Which types of unconformity do you see in the diagram?

Can you put the layers in order from youngest to oldest?

What is This?

Fossils• Fossil – traces or remains of living

things from long ago that help sort out the sedimentary rock record

• Index Fossils – fossils that are used as a “reference” to date other fossils

Types of Fossils

• BrainPOP Video

Fossil Samples

• Decide which type of fossil each sample is:

Homework• Vocab Set 2 – Days 1 & 2

• Other Ways of Determining Reading Comprehension with Questions (if not finished in

class)

Warm-Up• Update your Table of Contents• Get your vocabulary cards out to be checked

(remember I’m checking days 1 & 2)• Tape “Other Ways of Determining Age” into

page 16 of your Interactive NotebookDate Session

#Activity Page

#

9/17 8 “Other Ways of Determining Age” Reading Comprehension

16

Determining Age Note Guide 17

Silent Stations Skill Practice Answer Sheet 18

Review

• What were some things we talked about last class that help us determine how old

Earth really is?

Relative Age• Relative Age - the age of an event or

object in relation to other events or objects

–Use words like older, younger, around the same time, etc…

Time for more specific evidence…

Absolute Age• Absolute Age - The actual age of an

event or object– Use techniques to figure out actual age

• Radioactive dating, carbon dating

Lived:

1 million years ago

2 million years ago

3 million years ago

4 million years ago

Types of Dating• Radioactive (Radiometric) Dating – If you

know how much radioactive material was initially present in the sample and you know the half-life of the material, you can calculate the age of the sample.

• Carbon Dating – Using the amount of carbon in fossil remains to determine the age (sample must have been alive to use carbon dating)

What’s a “half-life?”• Half-life – the length

of time it takes for half of the atoms in a sample of a radioactive to change

• This break down occurs at a constant rate depending on the substance

Types of Dating

• BrainPOP Video – Carbon Dating

• Half-life Practice

Questions??

“SILENT STATIONS”

Be sure to tape the station guide into your notebook!

Homework•Vocab Set 2 – Day 3