Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Carbon 14
Name: Keith P.
Status: student
Age: 17
Location: N/A
Country: N/A
Date: 1999-2001


Question:
I have a few questions about radioactive materials. But first I need to ask one thing: When (for an example) Carbon 14 decays it decays into Nitrogen 14. We know that. But how does this happen? I'm not sure, but this is how I understand it, this is also my biggest question.

carbon 14 is unstable. when a subatomic particle, (i'm guessing an electron?) enters the atom, the atom reacts to this and splits into two or more atoms (in this case N-14) Meaning the whole Carbon 14 atom disappears and creats a few other stable atoms (N-14).

Ok, now for another part of my question. We know that temperature and other factors will change the speed of electrons and even the speed of light, since we have no been able to slow light down to 38 MPH. We know that neither the speed of electrons or light are constants. So let us say that there's a C-14 atom near absolute zero. This would mean the electrons in and outside of the C-14 atom are traveling A LOT slower than at room temperature. So wouldn't this mean that when the reaction occurs to split into the N-14 that it would occur much slower than usual? And the oppisite must equally be true. We know that heat has the oppisite effect, it actually makes the electrons travel faster! If the c-14 is exposed to extreme heats then the decaying (the reaction of the C-14 atom) would occur much faster.

Let's say that there are 10 moles of C-14 sitting around. If it's exposed to extreme heat, let's say enough heat that it had a half life of 5 days. now if we discovered this batch of c-14 100 years later we would assume that it has always been decaying at the same rate, because we did not know about the extreme heat it was exposed to 100 years prior to it's discovery. This would ultimately throw off the calculations, since the decaying of it has not always been a


Replies:
Kieth,

Regarding the transformation of C-14 to N-14: Given that C-14 is made of 6 protons and 8 neutrons -- and N-14 is composed of 7 protons and 7 neutrons, ask yourself what must be ejected from the C-14 nucleus to leave a N-14 nucleus. C-14 decays by emission of a beta particle (an electron). Emission of an electron from the C-14 nucleus transforms one of its neutrons into a proton. Thus, the mass number remains the same and the atomic number increases by 1.

Regarding the remainder of your questions: I think you may have accepted a mixture of current, ground-breaking research and actual fact.

Cooling the atom does not slow down its electrons. Even at absolute zero, electrons continue their movement about the nucleus.

Heating a radioactive material does not appear to alter its decay rate.

Regarding the accuracy of isotopic dating methods: Indeed, certain assumptions made in order to make things work out ought to be carefully considered when assessing the validity of such age-determining methodologies.

It is assumed that decay rates are constant. -- that is, rates we measure today are assumed to be the same as rates throughout all history. Simply because we have no method of altering decay rates, is not sufficient to justify that assumption. We know very little about the conditions under which the elements were first formed -- and even that information is based on speculation and assumption. Certainly those conditions were different then than now.

It is assumed that daughter products used in dating come from only one parent source. That assumption may not be justified.

Regards,
ProfHoff


I do not know the full details of this subject. If anyone has additional information to give, please do so. What I do know is this:

When C-14 decays, it releases alpha or beta particles. I cannot recall which. In any case, this means that a proton is expelled. An electron or neutron may accompany that proton.

I do not know how temperature affects the rate of decay. It would make sense that at higher temperatures, the molecules move faster, resulting in a higher probability of rouge protons hitting other nuclei.

I do not believe that temperature has a huge impact on the speed of electron flow. The flow will actually become more efficient as the temperature decreases.

The Einstein-Boltzman condensate, which acts like a very large atom, only exists at near-zero Kelvin. There, light may slow down to 38 MPH. This is purely a property of that substance, and not a characteristic of light near absolute zero.

Carbon dating works under the assumption that a living creature has a natural ratio of C-14 to C-12. If heat can increase the rate of decay, the amount of heat would be so high that it would kill the creature and destroy its remains. So, I think that the data we get from carbon dating is fairly accurate (within the tolerances of the technology, of-course)

I hope this helps in answering your questions.

-Wil Lam



Click here to return to the General Topics Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (help@newton.dep.anl.gov), or at Argonne's Educational Programs

NEWTON AND ASK A SCIENTIST
Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory