Students, particularly Young-Earth Creationists, may come in with misconceptions about how the age of the Earth and of various parts of the fossil record were determined. Your Account. Explore Teaching Examples Provide Feedback. Teaching about Radiometric Dating Students, particularly Young-Earth Creationists, may come in with misconceptions about how the age of the Earth and of various parts of the fossil record were determined. For example, they may assume that the whole geologic timeline is based on radiocarbon dating, which only gives reliable results for dates back to 40, years before present Low, personal communication. Others will argue that decay rates could have changed Wise, , or that God could have changed them, which might result in too-old dates.
Which element is used by earth scientists for radioactive dating of rocks
This page has been archived and is no longer updated. Despite seeming like a relatively stable place, the Earth’s surface has changed dramatically over the past 4. Mountains have been built and eroded, continents and oceans have moved great distances, and the Earth has fluctuated from being extremely cold and almost completely covered with ice to being very warm and ice-free.
Nothing good can last—and in the case of carbon, a radioactive isotope found in Earth’s atmosphere, that’s great news for archaeologists.
The use of carbon, also known as radiocarbon, to date organic materials has been an important method in both archaeology and geology. The technique was pioneered over fifty years ago by the physical chemist Willard Libby, who won the Nobel Prize for his work on 14 C. Since then, the technique has been widely used and continually improved. This paper will focus on how the radiocarbon dating method works, how it is used by scientists, and how creationists have interpreted the results.
Carbon is a radioactive isotope formed in the upper atmosphere. It is constantly being produced by a system in which cosmic rays from the sun hit atoms, releasing neutrons. The neutrons may then be absorbed by 14 N nitrogen atoms which lose a proton in the process, becoming 14 C. Carbon becomes a part of the mostly homogenous mixture of air in the atmosphere.
It can combine with other atoms and molecules such as oxygen to create carbon dioxide, or CO2. Through the process of photosynthesis, plants absorb carbon dioxide which contains 14 C along with the much more abundant 12 C and 13 C. Animals then eat the plants and incorporate 14 C into their own bodies, and eventually it is passed through the food chain. Through this process, every living thing eventually absorbs 14 C into its body in a measurable ratio to 12 C and 13 C.
MarketPlace for Science
The same was long true of the cosmos. The ancient Greeks Eratosthenes and Aristarchus measured the size of the Earth and Moon, but could not begin to understand how old they were. With space telescopes, we can now even measure the distances to stars thousands of light-years away using parallax, the same geometric technique proposed by Aristarchus, but no new technology can overcome the fundamental mismatch between the human lifespan and the timescales of the Earth, stars, and universe itself.
Despite this, we now know the ages of the Earth and the universe to much better than 1 percent, and are beginning to date individual stars. Our ability to measure ages, to place ourselves in time as well as in space, stands as one of the greatest achievements of the last one hundred years. In the Western world, the key to the age of the Earth was long assumed to be the Bible and its account of creation.
Two additional topics are added (Precambrian time and oxygen in the Earth’s atmosphere) that Cupps does not discuss in his book, but the.
Slideshows Videos Audio. Here of some of the well-tested methods of dating used in the study of early humans: Potassium-argon dating , Argon-argon dating , Carbon or Radiocarbon , and Uranium series. All of these methods measure the amount of radioactive decay of chemical elements; the decay occurs in a consistent manner, like a clock, over long periods of time. Thermo-luminescence , Optically stimulated luminescence , and Electron spin resonance.
All of these methods measure the amount of electrons that get absorbed and trapped inside a rock or tooth over time. Since animal species change over time, the fauna can be arranged from younger to older.
Teaching about Radiometric Dating
When asked for your age, it’s likely you won’t slip with the exception of a recent birthday mistake. But for the sprawling sphere we call home, age is a much trickier matter. Before so-called radiometric dating, Earth’s age was anybody’s guess. Our planet was pegged at a youthful few thousand years old by Bible readers by counting all the “begats” since Adam as late as the end of the 19th century, with physicist Lord Kelvin providing another nascent estimate of million years.
Kelvin defended this calculation throughout his life, even disputing Darwin’s explanations of evolution as impossible in that time period. In , Marie Curie discovered the phenomenon of radioactivity, in which unstable atoms lose energy, or decay, by emitting radiation in the form of particles or electromagnetic waves.
Scientists estimate that the Earth is about 4. To understand how this process works, you need to know a little bit about atoms and isotopes. Often, any one atom has several different forms, called isotopes. Atoms are made up of electrons, protons, and neutrons, and the number of electrons and protons determines the type of atom.
Hydrogen, for example, has one electron and one proton. Sometimes, it also has a neutron, in which case it is called deuterium.
How is Earth’s Age Calculated?
Some seem as fresh as if they were laid down yesterday. But how old are they, really? Scientists are now dating these ancient volcanic eruptions with a method that involves a curious kind of clock—the cosmic rays emitted by stars. Strawberry Crater Credit U. Forest Service Listen Listening
This dating scene is dead. Paleomagnetism. Earth’s magnetic polarity flip-flops about every , to , years. The polarity is.
All rights reserved. Professor Willard Libby, a chemist at the University of Chicago, first proposed the idea of radiocarbon dating in Three years later, Libby proved his hypothesis correct when he accurately dated a series of objects with already-known ages. Over time, carbon decays in predictable ways. And with the help of radiocarbon dating, researchers can use that decay as a kind of clock that allows them to peer into the past and determine absolute dates for everything from wood to food, pollen, poop, and even dead animals and humans.
While plants are alive, they take in carbon through photosynthesis. Humans and other animals ingest the carbon through plant-based foods or by eating other animals that eat plants. Carbon is made up of three isotopes.
Rethinking Radiometric Dating
Aristotle thought the earth had existed eternally. Roman poet Lucretius, intellectual heir to the Greek atomists, believed its formation must have been relatively recent, given that there were no records going back beyond the Trojan War. The Talmudic rabbis, Martin Luther and others used the biblical account to extrapolate back from known history and came up with rather similar estimates for when the earth came into being.
Within decades observation began overtaking such thinking. In the s Nicolas Steno formulated our modern concepts of deposition of horizontal strata.
But is radioactive dating valid? With decades of experience in top nuclear physics laboratories, Dr. Vernon Cupps tackles this question from a scientific and biblical perspective. He shows how radiometric dating methods make assumptions that cannot be verified and examines the significant problems with the radioactive dating methodology currently employed by secularists. The first entry in ICR’s In-Depth Science series, Rethinking Radiometric Dating goes into detail about the major radiometric dating methods, including potassium-argon, rubidium-strontium, uranium-lead, and others.
Cupps also examinse thermoluminescence dating, Earth’s magnetic field, radiohalos, zircons, radiocarbon dating, and soft tissue in fossils to uncover what the evidence actually reveals about Earth’s age.