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100 Greatest Discoveries: Radiometric Dating
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100 Greatest Discoveries: Radiometric Dating

When an American chemist discovered a century ago that radioactive uranium in rock formations decayed into lead, he gave scientists a tool they’ve been using ever since.

Examine how this scientific breakthrough led to better calibrating the age of the Earth and its geologic history in the Grand Canyon and throughout the world.

Science Channel
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Carbon Dating

Carbon Dating

In addition to using carbon, scientists use other elements to find out the age of fossils. Together, their dating methods have revealed the story of life on Earth. More...

Video
Huffington Post/AOL
Oldest Living Tree Found in Sweden

Oldest Living Tree Found in Sweden

This Norwegian spruce's 9,550-year-old root system is credited to the conifer's "ability to clone itself." See how scientists determined its age and why it's expected to keep living for a very long time. More...

Article
National Geographic
Carbon Dating Gets a Reset

Carbon Dating Gets a Reset

Tree rings, corals, and mud from a Japanese lake have been helping scientists make carbon-14 dating even more accurate.

More...

Article
Scientific American
The Grand Age of Rocks

The Grand Age of Rocks

How do geologists determine the ages of the rocks in the Grand Canyon, a park that covers over a million acres? Get the answer in this 'short primer on geologic dating methods." More...

Article
National Park Service
Zircon Chronology: Dating the Oldest Material on Earth

Zircon Chronology: Dating the Oldest Material on Earth

The mineral zircon is so durable it can survive geological events. Dive deeper into geochronology with this case study. More...

Article
AMNH
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A Popcorn Model for Radioisotopic Dating

A Popcorn Model for Radioisotopic Dating

By observing the "decay" of Kernelite into Popcornium, you can figure out the half-life of kernelite and tell how long the popcornium was in the microwave, without looking at the timer! More...

Activity
NM Bureau of Geology and Mineral Resources
Absolute Dating Rock Layers

Absolute Dating Rock Layers

It’s usually a given that the oldest rocks are on the bottom, but if scientists want actual dates, they choose the best absolute dating method. Take up the challenge for six layers of rock. More...

Interactive
University of Waikato
Absolute Dating: Radiometric Dating

Absolute Dating: Radiometric Dating

The method of radiometric dating is a powerful tool that helps scientists delve into our planet’s prehistory. Find out the role that radioactive elements play in this scientific endeavor. More...

Article
Smithsonian
Age of Rocks on the Atlantic Seafloor

Age of Rocks on the Atlantic Seafloor

Take a look at the bottom of the Atlantic Ocean, where the varying ages of rocks shows the rate at which the seafloor is spreading. More...

Activity
McDougal Littell
Coral Age Dating

Coral Age Dating

Travel in your virtual submersible to see if you can use radiometric dating to determine the age of dead and living corals. More...

Interactive
NOAA
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Dating Fossils in the Rocks

Dating Fossils in the Rocks

It's easy to tell the ages of skulls and other bones found in a type of sedimentary rock called tuff. Tuff contains radioactive elements that make it ideal for radiometric dating. More...

Article
National Geographic
Halflife

Halflife

You've heard about people seeing their lives flash before their eyes. In this interactive, it's an isotope's half-life you watch speed past. And you don't even have to be on the verge of dying to do it! More...

Interactive
University of Colorado
How Do Geologists Know How Old a Rock Is?

How Do Geologists Know How Old a Rock Is?

Nothing beats radiometric dating when it comes to establishing the age of ancient things. But scientists also get clues from the way rocks are layered and from the fossils they contain. More...

Article
Utah Geological Survey
How We Discovered the Age of the Earth

How We Discovered the Age of the Earth

Even without radiometric dating, scientists began to figure out the vast age of the Earth, its species, and its rocks. Here's how they did it. More...

Article
Ars Technica
Probing question: What Is a Molecular Clock?

Probing question: What Is a Molecular Clock?

As DNA copies itself, random errors build up at a steady rate. So, by comparing the DNA of different species, scientists can tell how long ago they shared a common ancestor. More...

Article
Phys.org
Radioactive Dating Game

Radioactive Dating Game

Carbon-14 and uranium-238 are radioactive, but have no worry here. Try your hand at different methods of radiometric dating and watch how decay and half-life work. More...

Video
PhET
Radiocarbon Dating

Radiocarbon Dating

Archaeologists rely on radiocarbon dating to date wood, bone, and other organic objects. Watch to learn how the disappearing atom carbon-14 can help reveal the date of an ancient artifact. More...

Video
NOVA/PBS
Radiometric Dating

Radiometric Dating

Radioactive decay means that rock can serve as a clock to peer way back in time. Investigate how it helps scientists measure billions of years into the distant past. More...

Article
NOVA/PBS
Radiometric Dating: Playing Half-Life Odds

Radiometric Dating: Playing Half-Life Odds

When it comes to answering the question "How old is that rock?" scientists turn to radiometric dating. Roll the dice to get a hands-on look at how an isotope decays. More...

Activity
Science Buddies
Relative Dating of Rocks Using Fossils

Relative Dating of Rocks Using Fossils

Find out how William Smith — an "obscure British canal surveyor" — helped trigger a scientific revolution when he created the first geological map of England in 1815. More...

Profile
University of California Museum of Paleontology
The Dating Game

The Dating Game

Words and graphics work together here, explaining everything from how carbon-14 forms in the atmosphere to how it reveals the age of ex-living things. More...

Article
NOVA/PBS

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