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 youngest.

Important Science Dates: Mon. 3/7: Rock layer puzzles packet due Wed. 3/9: Sign-up Future Paleontologist Presentations Thurs. 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 Starter 1.How are Relative Dating & Absolute Dating Similar? How are they different? SimilaritiesDifferences

3/9: Science Starter 1.How are Relative Dating & Absolute Dating Similar? How are they different? SimilaritiesDifferences 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 atoms 3. 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 Dating Chapter 6, section 3

Cassette Tapes-1970s-90s iPods-10/23/2001 CDs-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 material Daughter 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 years 2. Uranium-Lead Method: Uranium  Half-life = 4.5 billion years 3.Rubidium-Strontium Method: Rubidium  Half-life = 49 billion years 4.Carbon-14 Method: Carbon  Half-life = 5,730 years

Johnsonium 1027: half life of 5 years Schmelingium % Keefeium 0 half-life 50% Keefeium 50% Meyerium 1 half-life 25% Keefeium 75% Meyerium 2 half-lives 5 Years

Uranium 235: half-life 700 million yrs Lead % Uranium % Lead % Uranium % Lead million years old 1400 million y.o. 100% Uranium 235 0% Lead 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 history  Determine 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?