Carbon dating beta decay
Well, we're going to use exactly the same equation.So we'll say alright, the amount at 10,000 is equal to the initial amount that I started with 1.3 times 10 to the -12 times a half to the 10,000 divided by 5700. And when you do so, you'll end up with 0.385 times 10 to the -12. And if you type that in your calculator you'll find that this specimen is 700, oh sorry, 7860 years dead. So that's the way that we can do these calculations. Let's do it a different, let's do a different one.It's always the same thing and if you're having trouble in going from this step to this step, make sure you know how to do that. We take the natural log of both sides and then we solve for t. Let's say that a specimen has been dead for 10,000 years and I want to know its carbon 14 ratio.In 1892, Antoine-Henri Becquerel was appointed to hold the physics chair there as well.Marie Curie was one of Becquerel’s students that he greatly influenced.It decays with a half life of 5700 years into nitrogen 14 and electron and an electron antineutreno. So for that reason, every living thing that is interacting with its environment is expected to have this natural abundance of carbon 14. But when something dies, now it's not interacting with the environment anymore. We know that the amount at time t is equal to the initial amount times one half to the time over the half life, alright?So this is just an ordinary beta decay process and this carbon fourteen's half life is way way way too short for any carbon to just kind of exist naturally in the atmosphere, you'd think, not quite right. So that mean that 1.3 times 10 to the -12 carbon 14 atoms, exist for each and every carbon 12 atom in nature. So you'd think that if you got this 1.3 times 10 to the -12 carbon 14 atoms for each carbon 12 atom at some time, well then 5700 years later, half of the carbon 14 will have decayed. But in fact what happens is, cosmic rays from the sun interact with the upper atmosphere and they actually create carbon 14, at this rate so that in equilibrium, 1.3 times 10 to the -12 carbon 14 atoms will exist for every carbon 12 atom. It's no longer replenishing its carbon 14 supply. This is our standard radioactive decay formula, always works.
The 1908 Nobel Prize in Chemistry was awarded to Rutherford, and he was knighted in 1914.So, if you're trying to use his to date dinosaurs, just stop. Antoine-Henri Becquerel (1852-1908) was the first to discover radioactivity. His father and grandfather both had held the physics chair at the National Museum of Natural History in France.Carbon dating uses an unstable isotope of carbon to find the date of dead substances.This isotope Carbon-14 has a half life of 5,700 years.
This was an unexpected discovery, as the plates were only expected to fog if exposed to light.