science today :
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Science Today :. Future Paleontologist Project Presentations Today’s We’ll also Hand In: EH Unit Study Guide Rock Layer Puzzles Packet (if you still have this) “Time Marches On” Reading Guide (6.1). 3/7: Science Starter. List the rock layers & events in order from oldest to - PowerPoint PPT PresentationTRANSCRIPT
Science Today:Future Paleontologist Project
Presentations
Today’s We’ll also Hand In:• EH Unit Study Guide• Rock Layer Puzzles Packet (if you still have
this)• “Time Marches On” Reading Guide (6.1)
3/7: Science StarterList the rock layers & events in order from oldest toyoungest.
Important Science Dates:
Mon. 3/7: • Rock layer puzzles packet dueWed. 3/9: • Sign-up Future Paleontologist
PresentationsThurs. 3/10: • EH Unit Test (& study guide due)• Future Paleontologist Application Projects
Due (Presentations will start today) Fri. 3/11: • Future Paleontologist Presentations-cont.
Important Dates: Thurs. 3/10: EH Unit Test •Application Project Presentations•EH Study Guide Due
Fri. 3/11: •Application Project Presentations-cont.
3/9: Science Starter1. How are Relative Dating & Absolute Dating
Similar? How are they different?
Similarities Differences
3/9: Science Starter1. How are Relative Dating & Absolute Dating
Similar? How are they different?
Similarities Differences
• Both try to find out how old an object is
Relative: (a comparison)•Find whether something is older or younger than another object. •Law of Superposition Absolute: •Find the exact age of an object•Radiometric dating
Science Starter 3/8:1. True or False? Most organisms that have lived on
Earth died and decomposed without leaving a fossil.
2. After 1 half life, what are the percentages of unstable atoms and stable atoms in a radioactive element?
• A. 100% unstable atoms, 0% stable atoms• B. 50 % unstable atoms, 50% stable atoms• C. 25% unstable atoms, 75% stable atoms3. Mrs. Keefe’s friend has 2 naughty dogs that she
frequently has to dog-sit (It’s horrible!) . Atza is 4 years old and Coby is 1 year old. Do you know the dogs’ relative or absolute ages?
3/7 Science Starter: 1. What word describes the time it
takes for half of a radioactive sample to decay?
2. Name 2 types of radiometric dating.3. If anyone brings cookies as part of
their application project, what must we not let Blake do?
2/28: Science Starter: Use your book, chapter 6, section 3 to find the answers to the following questions.1. What is absolute dating? 2. What word describes the time it
takes for half of a radioactive sample to decay?
3. Name 2 types of radiometric dating.
Absolute DatingChapter 6, section 3
Cassette Tapes-1970s-90s
iPods-10/23/2001CDs-1980s
Records-early 1900s
8-Tracks-1960s-80s
Absolute Dating: determining the actual age in years of an event or object.
Radioactive Dating of Rocks:
To determine the actual age of a fossil or rock scientists use radioactive dating and element half life to determine the ages of rocks (Absolute Dating)
Isotope: An atom with the same # of protons but with different # of neutrons. • Some isotopes are radioactive
(unstable)
Isotopes-cont.• Unstable Isotopes will change (& try to
become more stable) over time
• An Unstable Isotope (radioactive)works towards stability and changes into another kind of element.
Ex. Potassium-40 decays to argon and calcium.
Radioactive Decay:
• Radioactive decay – The process where radioactive substances (unstable) break down (change) into more stable substances.
• Occurs at a steady (predictable)rate
Radioactive decay (p. 162)
Unstable
Stable
The decay process occurs at a steady, constant rate
Radiometric Dating: (ratio)
Parent materialDaughter material
Radiometric Dating of Rocks:
Radiometric Dating: process of determining the exact age of a sample, based upon the ratio of parent material (old stuff) to daughter material (new stuff) .
Half Life: the length of time it takes for half of the radioactive atoms to change from an unstable form into a stable form (p. 163)• When rock forms = 100% unstable,
0% stable• After 1 half life = 50% unstable 50%
stable• After 2 half lives = 25% unstable 75%
stable
Types of Radiometric Dating
1. Potassium-Argon Method: • Potassium Half-life = 1.3 billion
years2. Uranium-Lead Method:• Uranium Half-life = 4.5 billion years3. Rubidium-Strontium Method:• Rubidium Half-life = 49 billion years4. Carbon-14 Method: • Carbon Half-life = 5,730 years
Johnsonium 1027: half life of 5 yearsSchmelingium 327
100% Keefeium 0 half-life
50% Keefeium50% Meyerium 1 half-life
25% Keefeium75% Meyerium2 half-lives
5 Year
s
5 Year
s
Uranium 235: half-life 700 million yrsLead 207
50% Uranium
235
50% Lead 207
25% Uranium
235
75% Lead 207
700 million years old
1400 million y.o.
100% Uranium
235
0% Lead 207
2 half-lives 1 half-life
0 half-lives
Rock Formation 0 years old
Objectives: (you should be
able to…)•Explain how fossils are used to establish the Earth’s historyDetermine the difference between absolute and relative time
Know the importance of index fossils in geologic time
Understand how half life is used to date rocks
Understand where fossil fuels come from and the difference between renewable and nonrenewable resources
1. True or False? Most organisms that have lived on Earth died and decomposed without leaving a fossil.
2. After 1 half life, what are the percentages of unstable atoms and stable atoms in a radioactive element?
• A. 100% unstable atoms, 0% stable atoms• B. 50 % unstable atoms, 50% stable atoms• C. 25% unstable atoms, 75% stable atoms
3. One example of a nonrenewable resource is ___________.
• A. wind power• B. coal• C. wood
4. Ms. Johnson’s friend has 2 naughty dogs that she frequently has to dog-sit (It’s horrible!) . Atza is 4 years old and Coby is 1 year old. Do you now know the dogs’ relative or absolute ages?