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 DateSession # ActivityPage # 9/13 7Earth’s Age & Evidence Note guide 14 Law of Superposition Practice15

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 Notebook DateSession # ActivityPage # 9/17 8“Other Ways of Determining Age” Reading Comprehension 16 Determining Age Note Guide17 Silent Stations Skill Practice Answer Sheet18

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