Up to now, all we have learned is RELATIVE dating/aging.

Up to now, all we have learned is RELATIVE dating/aging…SUPERPOSITION

Up to now, all we have learned is RELATIVE dating/aging…SUPERPOSITION NOT EXACT JUST COMPARING

But remember when I told you the ages of cockroach fossils? 49 million years old 125 million years old

Recall how I’ve told you that evidence shows the Earth is about 4 Recall how I’ve told you that evidence shows the Earth is about 4.5 billion years old?????

How do we know the ABSOLUTE date our Earth?

Remember Le Comte de Buffon’s tried to ABSOLUTELY age of Earth!

But he didn’t know about RADIOACTIVE HEATING from UNSTABLE ATOMS Our crust holds in a lot of heat. Buffon didn’t consider radioactive heating! My steel balls weren’t radioactive like Earth!

Remember, everything is made of atoms. Positive protons (+) Neutral neutrons (o) Swirling electrons (-)

TOO MANY NEUTRONS make ATOMS RADIOACTIVE! Positive protons too many neutrons Swirling electrons

The biggest atoms below are most unstable. (They are most radioactive Most likely have an abnormal number of neutrons (o).

the bigger the atom, the more neutrons numbers can vary The biggest atoms below are most unstable. (They are most radioactive.) the bigger the atom, the more neutrons numbers can vary

Even a small percent of carbon atoms are unstable.

But, even a small percent of carbon atoms are unstable. Carbon-14 is a RADIOACTIVE atom of carbon

Unstable things DECAY. AND GIVE OFF HEAT!!!

Unstable RADIOACTIVE ATOMS DECAY…. …AND GIVE OFF radioactive HEAT!!!

Unstable RADIOACTIVE ATOMS DECAY…. …AND GIVE OFF radioactive HEAT!!!

Why is the center of our Earth hot? REASON 1 REASON 2 REASON 3 Heavy bombardament early on! Our crust acts like a pressure cooker! Radioactive elements keep getting cooked up below our feet.

Unstable RADIOACTIVE ATOMS DECAY like CLOCKWORK! Unstable radioactive atoms decay back into stable atoms, but usually over a long time!

Right now, a small percent of you is made of radioactive Carbon-14 atoms.

illustrate with Kollar blocks.

After you die, HALF of your radioactive C-14 atoms decay into more stable nitrogen atoms EVERY 5,700 years. decay On average, HALF your unstable carbon-14 atoms change into a normal nitrogen atom every 5,730 years.

After you die, HALF of your radioactive C-14 atoms decay into more stable nitrogen atoms EVERY 5,700 years. decay On average, HALF your unstable carbon-14 atoms change into a normal nitrogen atom every 5,730 years. So if the preserved remains of this mammoth has only HALF the C-14 as today’s elephant, it is 5,700 years old!

After you die, HALF of your radioactive C-14 atoms decay into more stable nitrogen atoms EVERY 5,700 years. decay On average, HALF your unstable carbon-14 atoms change into a normal nitrogen atom every 5,730 years. So if the preserved remains of this human has only 1/4th the C-14 as today’s human, it is _________ years old!

After you die, HALF of your radioactive C-14 atoms decay into more stable nitrogen atoms EVERY 5,700 years. decay On average, HALF your unstable carbon-14 atoms change into a normal nitrogen atom every 5,730 years. So if the preserved remains of this human has only 1/4th the C-14 as today’s human, it is 11,400 years old! 2 x 5,700 = 11,400

After you die, HALF of your radioactive C-14 atoms decay into more stable nitrogen atoms EVERY 5,700 years. decay On average, HALF your unstable carbon-14 atoms change into a normal nitrogen atom every 5,730 years.

We use radioactive Cesium-137 as our WORLD CLOCK! check our phones! RADIOACTIVE ATOMS DECAY in NEAR PERFECT TIME. We use radioactive Cesium-137 as our WORLD CLOCK!

Each time HALF the radioactive atoms decay, we call that a HALF-LIFE! For carbon-14 that is every 5,700 years. 5700

It takes 5,700 years for a half –a-piece of Carbon-14’s to decay. 5700 5700

Carbon-14’s half-life is 5,700 years! Number of half-lives Percent (%) of Carbon-14 How many years go by? 100% None 1 50% or half 5,700 (1 x 5,700) 2 25% or ¼ (quarter) 11,400 (2 x 5,700) 3 12.5% or 1/8th 17,100 (3 x 5,700) 4 6.25% or 1/16th 22,800 (4 x 5,700)

Half of radioactive uranium-235 (U-235) changes into lead (Pb) every 704 million years!

Uranium-235 half-life is 704 million years! 704 MY

Uranium-235 half-life is 704 million years! 704 MY 704 MY

Uranium-235 half-life is 704 million years! Number of half-lives Percent (%) of Uranium-235 How many years go by? None 1 50% or half 2 1,408 million years 3 12.5% or 1/8th 4 2.816 billion years

Radioactive absolute dating measuring Carbon -14 or Uranium-235 in fossils and rocks gets pretty exact .

Trosclair’s worksheet…

Bill Nye fossils… Go over…end. https://www.youtube.com/watch?v=_xKPgqx5kX8

end 2015-16

By monitoring & measuring the decay of 14C & 235U into more stable atoms, WE CAN ABSOLUTELY DATE RECENT RELICS…

By monitoring & measuring the decay of 14C & 235U into more stable atoms, WE CAN ABSOLUTELY DATE RECENT RELICS… like this 42,000 year old mammoth

By monitoring & measuring the decay of carbon & uranium isotopes into more stable atoms, WE CAN ABSOLUTELY DATE RECENT RELICS… like this 42,000 year old mammoth found in ice!

By monitoring & measuring the decay of 14C & 235U into more stable atoms, WE CAN ABSOLUTELY DATE RECENT RELICS… we can ABSOLUTELY DATE ANCIENT FOSSILS & LAYERS OR ROCK like this 42,000 year old mammoth

By monitoring & measuring the decay of 14C & 235U into more stable atoms, WE CAN ABSOLUTELY DATE RECENT RELICS… we can ABSOLUTELY DATE ANCIENT FOSSILS & LAYERS Of ROCK like this 42,000 year old mammoth like this 155 million year old ichthyosaur from China.

http://www. dailymail. co http://www.dailymail.co.uk/sciencetech/article-1340756/Massive-haul-20-000-ancient-fossils-China-life-Earth-bounced-biggest-mass-extinction-time.html

Absolute radioactive dating rules over relative superposition dating

You will work in pairs…. Each get paper to make a graph, yardstick, & marker.

You will work in pairs. Each get paper to make a graph, yardstick & marker. Will get about 100 beans. Count and get rid of bad ones (busted, painted on both sides, etc.)

Count out 100 white/black beans. Make a simple graph rate of decay half-lives

Count out 100 white/black beans. Make a simple graph (10 decameters on the y axis. 100% rate of decay 10% half-lives

Count out 100 white/black beans. Make a simple graph (10 decameters on the y & x axis. 100% . rate of decay 10% 1 2 5… half-lives

Mr. G will assign groups of 4. Each get paper to make a graph, yardstick & marker. Will get about 100 beans. Count and get rid of bad ones (busted, painted on both sides, etc.) Pile the 100 best beans into a cup and gently shake it up.

Mr. G will assign groups of 4. Each get paper to make a graph, yardstick & marker. Will get about 100 beans. Count and get rid of bad ones (busted, painted on both sides, etc.) Pile the 100 best beans into a cup and gently shake it up. Tally up the ones that stayed white. Report your results as the 1st half –life.

Next…

Next… Put the black stable beans in the extra cup and keep these aside.

Next… Put the black stable beans in the extra cup and keep these aside. Take the remaining “unchanged” white beans and return them to your shaking cup.

Next… Put the black stable beans in the extra cup and keep these aside. Take the remaining “unchanged” white beans and return them to your shaking cup. Shake up these beans (gently) and spill them out onto your lab table. Count the “still radioactive” white beans this time and graph your results under 2nd half-life.

Repeat… Put aside the black beans and then put the remaining white beans in your shaking cup. Gently shake and then count the remaining “isotope” white beans. Graph this number as your 3rd half-life.

Repeat… Put aside the black beans and then put the remaining white beans in your shaking cup. Gently shake and then count the remaining “isotope” white beans. Graph this number as your 3rd half-life. Do the same for a 4th half-life…

Repeat… Put aside the black beans and then put the remaining white beans in your shaking cup. Gently shake and then count the remaining “isotope” white beans. Graph this number as your 3rd half-life. Do the same for a 4th half-life, 5th half life…

Repeat… Put aside the black beans and then put the remaining white beans in your shaking cup. Gently shake and then count the remaining “isotope” white beans. Graph this number as your 3rd half-life. Do the same for a 4th half-life, 5th half life, 6th half-life…

Repeat… Put aside the black beans and then put the remaining white beans in your shaking cup. Gently shake and then count the remaining “isotope” white beans. Graph this number as your 3rd half-life. Do the same for a 4th half-life, 5th half life, 6th half-life, 7th half-life…

Repeat… Put aside the black beans and then put the remaining white beans in your shaking cup. Gently shake and then count the remaining “isotope” white beans. Graph this number as your 3rd half-life. Do the same for a 4th half-life, 5th half life, 6th half-life, 7th half-life & 8th half-life.

compare each group’s graph.

Questions (write answers in notes): Did all the graphs tend to look the same?

Questions (write answers in notes): Did all the graphs tend to look the same? Can we count radioactive atoms the same way?

Questions (write answers in notes): Did all the graphs tend to look the same? Can we count radioactive atoms the same way? So explain how radioactive elements can help us date prehistoric rocks and fossils.

Clean-up…

Count out 100 white beans. If the white beans were made of uranium-235, in 704 million years, how many of these beans would turn to lead-207?

Count out 100 white beans. If the 100 white beans were made of uranium-235, in 704 million years, how many of these beans would turn to lead-207? 50…because the half-life of uranium-235 is 704 million years.

Count out 100 white beans. If the white beans were made of uranium-235, in 704 million years, how many of these beans would turn to lead-207? 50…because the half-life of uranium-235 is 704 million years. Replace 50 white “uranium” beans with 50 black “lead” beans…

Half your uranium-235 isotopes have turned to lead in 704 million years. If the white beans were made of uranium-235, in 704 million years, how many of these beans would turn to lead-207? 50…because the half-life of uranium-235 is 704 million years. Replace 50 white “uranium” beans with 50 black “lead” beans… …now 704 million years have gone by.

Half your uranium-235 isotopes have turned to lead in 704 million years. THAT’S HALF-LIFE! If the white beans were made of uranium-235, in 704 million years, how many of these beans would turn to lead-207? 50…because the half-life of uranium-235 is 704 million years. Replace 50 white “uranium” beans with 50 black “lead” beans… …now 704 million years have gone by.

How old would your sample be if you only found 25 white “uranium” beans? 100%50% uranium-235 atoms= 704,000,000 yrs.

How old would your sample be if you only found 25 white “uranium” beans? 100%50% uranium-235 atoms= 704,000,000 yrs. 50%25% uranium-235 isotope = 2 half-lives or…

How old would your sample be if you only found 25 white “uranium” beans? 100%50% uranium-235 atoms= 704,000,000 yrs. 50%25% uranium-235 isotope = 1,408,000,000 yrs old.

How old would your sample be if you only found 12 white “uranium” beans? 100%50% uranium-235 atoms= 704,000,000 yrs. 50%25% uranium-235 isotope = 1,408,000,000 yrs old. 25%12.5% uranium-235 atoms =

How old would your sample be if you only found 12 white “uranium” beans? 100%50% uranium-235 atoms= 704,000,000 yrs. 50%25% uranium-235 isotope = 1,408,000,000 yrs old. 25%12.5% uranium-235 atoms = 3 half-lives or

How old would your sample be if you only found 12 white “uranium” beans? 100%50% uranium-235 atoms= 704,000,000 yrs. 50%25% uranium-235 isotope = 1,408,000,000 yrs old. 25%12.5% uranium-235 atoms = 2,112,000,000 years old.

Each time 704 million years go by… Uranium-235 isotope atoms decrease by half!

How old would your sample be if you only found 6 white “uranium” beans? Remember, the half-life of uranium-235 is 704 million years.

How old would your sample be if you only found 6 white “uranium” beans? 100%50% uranium-235 atoms= 704,000,000 yrs. 50%25% uranium-235 isotope = 1,408,000,000 yrs old. 25%12.5% uranium-235 atoms = 2,112,000,000 years old. 12%6% uranium-235 atoms left = ???

How old would your sample be if you only found 6 white “uranium” beans? 100%50% uranium-235 atoms= 704,000,000 yrs. 50%25% uranium-235 isotope = 1,408,000,000 yrs old. 25%12.5% uranium-235 atoms = 2,112,000,000 years old. 12%6% uranium-235 atoms left = 4 half-lives or..

How old would your sample be if you only found 6 white “uranium” beans? 100%50% uranium-235 atoms= 704,000,000 yrs. 50%25% uranium-235 isotope = 1,408,000,000 yrs old. 25%12.5% uranium-235 atoms = 2,112,000,000 years old. 12%6% uranium-235 atoms left = 2,816,000,000 years old!

10050=704 mya 5025=1.408 bya 2512=2.116 bya 126=2.824 bya

Separate your beans! Count out 48 black beans.

Your 48 black beans represent 48 nitrogen atoms today.

Let’s assume that when a snorlax dies, it dies with 25% of its tissue contain- ing carbon-14. Replace 25% of your black nitrogen beans with white carbon-14 atom beans.

How many of a snorlax’s 48 nitrogen “atoms” would be carbon-14? Let’s assume that when a snorlax dies, it dies with 25% of its tissue contain- ing carbon-14. How many of a snorlax’s 48 nitrogen “atoms” would be carbon-14?

Let’s assume that when a snorlax dies, it dies with 25% of its tissue contain- ing carbon-14. How many of a snorlax’s 48 nitrogen “atoms” would be carbon-14? (.25 x 48 = ????

Let’s assume that when a snorlax dies, it dies with 25% of its tissue contain- ing carbon-14. How many of a snorlax’s 48 nitrogen “atoms” would be carbon-14? (.25 x 48 = 12)

Replace 12 of your 48 nitrogen “atoms” with 12 white carbon-14 isotopes.

Replace 12 of your 48 nitrogen “atoms” with 12 white carbon-14 isotopes. Now you have a new sample of fresh snorlax tissue! With its 25% carbon-14 isotopes

If white beans are Carbon-14 with a half life of 5730 years, how old is your snorlax fossil if you found only 6 white bean carbon-14 atoms amongst 42 nitrogen atoms?

Remember C-14 has a half-life of 5,730 years. 12 atoms6 atoms= # cut in half…HALF-LIFE

12 atoms6 atoms= 5,730 years…HALF-LIFE If white beans are Carbon-14 with a half life of 5730 years, how old is your snorlax fossil if you found only 6 white bean carbon-14 atoms amongst 45 nitrogen atoms? 12 atoms6 atoms= 5,730 years…HALF-LIFE

12 atoms6 atoms= 5,730 years…HALF-LIFE If white beans are Carbon-14 with a half life of 5730 years, how old is your snorlax fossil if you found only 3 white bean carbon-14 atoms amongst 45 nitrogen atoms? 12 atoms6 atoms= 5,730 years…HALF-LIFE

If white beans are Carbon-14 with a half life of 5730 years, how old is your snorlax fossil if you found only 3 white bean carbon-14 atoms amongst 45 nitrogen atoms? 12 atoms6 atoms= 5,730 years…HALF-LIFE 6 atoms 3 atoms = # cut in half…2nd HALF-LIFE

If white beans are Carbon-14 with a half life of 5730 years, how old is your snorlax fossil if you found only 3 white bean carbon-14 atoms amongst 45 nitrogen atoms? 12 atoms6 atoms= 5,730 years…HALF-LIFE 6 atoms 3 atoms = 11,460 years (2 half-lives)

126= 5730 years 63=11,460 years

What if your snorlax fossil had 9 carbon-14 isotopes in it? 126= 5730 years 63=11,460 years

What if your snorlax fossil had 9 carbon-14 isotopes in it? 126= 5730 years 63=11,460 years W’huh? 9

What if your snorlax fossil had 9 carbon-14 isotopes in it? 126= 5730 years 63=11,460 years W’huh? 9 Is it older than 5,730?

What if your snorlax fossil had 9 carbon-14 isotopes in it? 126= 5730 years 63=11,460 years Hmm. 9 Is it older than 5,730?

What if your snorlax fossil had 9 carbon-14 isotopes in it? 126= 5730 years 63=11,460 years I do not think so. 9 Is it older than 5,730? NO!

Look at a number line…

126= 5730 years

126= 5730 years ½ way

126= 5730 years; 129 = 5730/2 ½ way

126= 5730 years; 129 = 2865 yrs old. ½ way

A mammoth skin has been found with 0.002% of carbon-14… If most animal tissue today dies with 0.064% carbon-14, And the half life of the carbon-14 isotope is ____________ years.

A mammoth skin has been found with 0.002% of carbon-14… If most animal tissue today dies with 0.064% carbon-14, And the half life of the carbon-14 isotope is 5,730 years. Half of any remaining carbon-14 turns into nitrogen.

A mammoth skin has been found with 0.002% of carbon-14… If most animal tissue today dies with 0.064% carbon-14, And the half life of the carbon-14 isotope is 5,730 years. Half of any remaining carbon-14 turns into nitrogen. How many years would have gone by if carbon-14 levels are .032%?

A mammoth skin has been found with 0.002% of carbon-14… If most animal tissue today dies with 0.064% carbon-14, And the half life of the carbon-14 isotope is 5,730 years. Half of any remaining carbon-14 turns into nitrogen. How many years would have gone by if carbon-14 levels are .032%? Is it possible that this mammoth breaks the record for the most recent mammoth of 30,000 years ago?

Actually the most recent evidence of mammoth living on earth is 4,500 years ago. What would you expect the percent of carbon-14 in this mammoth sample?

Actually the most recent evidence of mammoth living on earth is 4,500 years ago. What would you expect the percent of carbon-14 in this mammoth sample? Assume tissue has 0.0064% carbon-14 at time of death.

Carbon-14 actually makes up 1/1,000,000,000 of carbon in living tissue. Now, with C-14 only being about one one-trillionth of the carbon in an object, it might seem that there would only be a few such atoms in a sample. Nope! A one-pound piece of wood contains about half a pound of carbon. Using Avogadro's number, we can calculate that there are around 1.1 * 1025 atoms of carbon in it. one one-trillionth of that is 1.1 * 1013 atoms of Carbon-14. That is 11,000,000,000,000 atoms of Carbon-14 in that single chunk of wood! It turns out that around 3,800 of those C-14 atoms would decay every minute, plenty to be measurable!

Clean-up.

Use Kollar bricks to do another radioactive dating problem.