Earth’s Age + Evidence
WARM UP
• Write a homework reminder – leave it to
be stamped!
• Update your Table of Contents for today!
• Tape your Vocab Quiz onto page 13
when you get it back!
Date
Session
#
11/20
&
11/21
7
Activity
Earth’s Age & Evidence Note guide
Page
#
14
Earth’s History Writing Prompt
Reminders
• Make sure it is submitted by the due date
regardless of whether you will be here
next week or not!
• You may add images to enhance your
essay!
• Please adhere to language arts standards
in terms of paragraph length, grammar,
citations & structure!
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
in the next few
lessons helps
answer the BIG
QUESTION!
Law of Superposition
• Law of Superposition–
• Under normal conditions, the
layers of sediment get older
the deeper you go
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…they
are 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
• An 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?
Quick Review!
• What is the only type of
rock that you would find
fossils in?
Fossils
• Fossil – traces or remains of living
things from long ago that help sort out
the sedimentary rock record
• Index Fossils – common fossils that are
used as a “reference” to date other
fossils
Types of Fossils
• BrainPOP Video
The Great Fossil Find
• Work together with your table partner to
determine what type of animal your fossil is!
The activity guide must be turned in by the
end of class for a grade!
http://www.indiana.edu/~ensiweb/lessons/g
r.fs.fd.html
READY TO FIND OUT WHAT THE
GREAT FOSSIL FIND WAS?
• Scaphognathus crassirostris was a
pterosaur, similar to a pterodactyl, that
lived during the Late Jurassic Period.
Scaphognathus crassirostris
• What it may have looked like…
Homework
1.
2.
Submit your Writing Prompt
by the due date!!!!
Bring a bag of Skittles for
the class after break!!!!
Warm-Up
• Write your homework – get it stamped!
• Update your Table of Contents for today!
• Get & complete the 2 mini Warm-Ups on the
counter…tape them into page 15!
Date
Session
#
12/1 &
12/2
8
Activity
Page
#
Mini Warm-Ups
15
Determining Age Note Guide
16
Skittles Half-Life Simulation
17
Review
• What Law do these mini warm-ups
demonstrate?
• What were some other things we
talked about last class that help us
determine how old Earth really is?
The Butler walks to work
The Handyman rides a bike
The Cook rides a motorcycle
The Maid drives a car
The Nephew has a seeing-eye dog
R
(layer E)
R
3
9
5
2
4
1
6
7
8
The evidence we looked at last
time was pretty general, it’s
time for evidence that can give
us more specific information…
Relative Age
• Relative Age - the age of an event or object
in relation to other events or objects
• Example: Fossil #2 is younger than Fossil
#1
Absolute Age
• Absolute Age – actual age of an event or
object; specific number is given
– Dating techniques like radioactive dating or
carbon dating are used to figure out actual age
Example: The shell is 2 million
years old
Isotope Review…They’re Back!
•
•
•
•
Carbon – 11
Carbon – 12
Carbon – 13
Carbon – 14
= Protons
= Neutrons
• Isotopes – versions
of the same element
with a different
mass because they
have a different
number of neutrons!
• Some versions are
stable and others
are radioactive!
• What makes up an
atom’s mass?
Types of Dating
Carbon Dating
Radioactive
(Radiometric) Dating
• Uses radioactive
carbon-14 isotopes
• Only good for
samples up to
60,000 years old
• Sample must have
been ALIVE!
• Uses other
radioactive isotopes
• Good for much
older samples
• Sample does NOT
have to have been
living!
What’s a “Half-life?”
• Half-life – length of
time it takes for half
of the atoms in a
radioactive isotope
to break down
• The break down
occurs at a constant
rate depending on
the radioactive
isotope being used!
Half-Life Example
• If the half-life of Titanium-44 is 63 years
and you start out with 80 grams of it,
how long will it take to decay?
# of Half-Lives Amount of Time
0
0
1
63
2
3
Grams of
Titanium-44
80
What Exactly is Radioactivity?
• BrainPOP Video - Radioactivity
Skittles Half-Life Simulation
• Make sure you have a cup of Skittles –
you may need to arrange for someone to
share with you!
• You will work where you are seated, but
you and your table partner can work
together.
• I want to see your work before you leave,
and I will be checking it off for a
grade…then you can tape it into page 17!
Homework
• Finish your Earth’s History
WebQuest if you did not
have time in class, or you
were absent last class!
• Finish your Skittles Lab if
you did not finish in class!
Warm-Up
• Write a homework reminder – get it stamped!
• Update your Table of Contents for today!
• Get your Skittles Lab out from last class to be
checked/go over it!
• If you have the WebQuest completed, put it in the
basket!
• Complete the Half-Life Warm-Up from the counter!
Date
12/3
&
12/4
Session
#
9
Activity
Page
#
Half-Life Warm-Ups
18
Silent Stations Answer Sheet –
FORMAL GRADE
19
Skittles Half-Life Simulation Review
Graph on the Back: A graph of the decay of a radioactive
isotope has a very specific shape…your lines for
Skittilium & Blankium should look like the graph below.
Skittles Half-Life Simulation Review
#2 on the back
• Iodine-131 is your radioactive isotope in
this scenario…
# of Half-Lives
Time of Half-Life
Amount of Iodine-131
Remaining
0
0
40 mg
1
8 days
20 mg
2
16 days
10 mg
3
24 days
5 mg
4
32 days
2.5 mg
Skittles Half-Life Simulation Review
#3 on the back:
• Does it give the name of the radioactive
isotope in the question? Does it give the
amount?
• What does it mean to be radioactive?
• What is an isotope?
• What is a half-life? What is the half-life of
this isotope?
• What is the significance of this half-life – in
other words, why should your mom not be
worried?
Radioactive Dating/Half-Life Practice
# of Half-Lives
Time
0
0
1
2
3
4
5
Amount of…
“SILENT STATIONS”
• You will rotate around the room quietly and
practice the concepts we have learned at each
station.
• I am the “Answer Key Station,” so once you
have completed everything you can come check
your answers!
• Be sure to tape the station guide into your
notebook on page 19 once you have checked
your answers and been checked off for a grade!
• Complete the homework for next class, or work
on an extra credit opportunity!!
Warm-Up
•
•
•
•
Write your homework – have it stamped!
Update your Table of Contents today!
Put your WebQuest in the basket!
If you did not get your Silent Stations
checked off, please have those out as well!
Date Session
#
12/5
&
12/8
10
Activity
Ice Cores & Tree Rings – Notes and
Lab
Page
#
19
Just a Few More Pieces of
Evidence…
We’ve already talked about:
• Law of Superposition
• Unconformities (Intrusion, Overturning,
Fault)
• Fossils/Index Fossils
• Absolute & Relative Age
• Carbon Dating & Radioactive Dating
We are missing:
• Ice Cores
• Tree Rings
Remember The Law of
Uniformitarianism? What Does it State?
• Law of Uniformitarianism: ? ? ?
• Climate change is part of that and the
climate can gradually change over
hundreds, thousands or millions of years.
• Ice cores and tree rings are tools to help
scientists figure out how the climate has
changed in the past.
Remember The Law of Superposition?
What Does it State?
• Law of Superposition: ? ? ?
• How do you think that ice cores and tree
rings are going to demonstrate this Law?
Ice Cores
• Ice Core - a tubular
sample of ice that
shows the layers of
snow and ice that
have built up over
thousands of years
literally freezing the
events of the past
What types of things do you think get “trapped”
in these ice cores?
Ice Cores
•
•
•
•
•
temperature records
atmospheric composition data
dust, ash or sediment
plant spores
bubbles of gas (usually CO2)
Pros and Cons?
Ice Cores
• Extreme Ice National Ice Core Lab
http://natgeotv.com/ca/extremeice/videos/national-ice-core-lab
http://earththeoperatorsmanual.com/segmen
t/5
Tree Rings
• Another tool for studying climate change
over the life span of the tree
• The width of tree rings varies, depending
on how much the tree grows in various
years
• Thick ring = good year for growth
• Thin ring = poor growth, little rainfall
Pros and Cons?
Tree Ring Practice
B
D
A
C
Tree Rings
Lord of the Tree Rings
• http://www.youtube.com/watch?v=FAOYkx
8E-Gc
Ice Core & Tree Ring Lab Roles
• Supply Manager – retrieves and returns
supplies
• Reader/Discussion leader – reads the
directions and the questions and
ensures there is a discussion
• Scribe – makes sure everyone knows
what to write, and is writing
• Speaker – shares information with the
class
Ice Core Lab
• Send your supply manager to get a
piece of paper towel from one of the
sinks.
• Your group will receive 1 ice core
sample - peel the paper off and follow
the directions!
• Be sure to answer all of the questions
and be ready to share in 5 minutes!
Tree Ring Lab
• Send your supply manager to your sink and
simply set your ice core in the sink to melt
– throw away the paper towel!
• Your group will receive several tree ring
samples – read and follow the directions!
• Be sure to answer all of the questions!
• After everyone has finished, have your
supply manager return ALL tree rings!
The Birth of the Earth
• http://www.youtube.com/watch?v=JQ93Ms
M8KFI
• A great recap as well as a lot we didn’t get
a chance to talk about!