Potassium 40 dating calculator

How much Potassium-40 is in the rock sample?

At the present time, all natural potassium is 0.012% potassium-40. Thus, the quantity of potassium-40 currently in the rock sample is: The 6.0 micrograms of argon came from the decay of potassium-40. Potassium-40 decays to calcium-40 89% of the time and to argon-40 11% of the time.

What is potassium-argon dating?

Potassium-argon dating is a technique used to determine the age of rocks. Because argon is a noble gas, it does not form compounds and remains a gas, trapped in the solid rock.

What is the half life of potassium 40?

Problem. All natural potassium is 0.012% potassium-40, a radioactive isotope with a half-life of 1.2 billion years; the rest consists of stable isotopes of potassium. Potassium-40 has two ways to decay, producing calcium-40 89% of the time and argon-40 11% of the time.

What is the rate of decay of potassium-40?

Potassium-40 has two ways to decay, producing calcium-40 89% of the time and argon-40 11% of the time. What is the crustal abundance of potassium-40 in parts per million? What was the crustal abundance of potassium-40 just after the Earth formed, 4.5 billion years ago? How much potassium-40 has decayed away in the last 4.5 billion years, in kg?

How many grams of potassium are in a rock sample?

A rock sample is found to contain 1.00 gram of potassium and 6.0 micrograms of argon. How old is the rock? At the present time, all natural potassium is 0.012% potassium-40.

What is potassium 40 (P40)?

Potassium 40 is a radioisotope that can be found in trace amounts in natural potassium, is at the origin of more than half of the human body activity: undergoing between 4 and 5,000 decays every second for an 80kg man. Along with uranium and thorium, potassium contributes to the natural radioactivity of rocks and hence to the Earth heat.

What is the half life of potassium 40?

Problem. All natural potassium is 0.012% potassium-40, a radioactive isotope with a half-life of 1.2 billion years; the rest consists of stable isotopes of potassium. Potassium-40 has two ways to decay, producing calcium-40 89% of the time and argon-40 11% of the time.

How many atoms of argon-40 are in potassium-40?

Suppose you find a rock originally made of potassium-40, half of which decays into argon-40 every 1.25 billion years. You open the rock and find 31 atoms of argon-40 for every atom of potassium-40.

What is the decay of potassium 40?

Potassium-40. The radioactive decay of this particular isotope explains the large abundance of argon (nearly 1%) in the earths atmosphere, as well as its abundance compared to 36 Ar. Very rarely (0.001% of the time) it will decay to 40 Ar by emitting a positron (β +) and a neutrino.

What is the half life of potassium 40 isotope?

Isotope of potassium. Potassium-40 (40K) is a radioactive isotope of potassium which has a very long half-life of 1.251×109 years. It makes up 0.012% (120 ppm) of the total amount of potassium found in nature.

How to calculate the 40 K decay half-life?

There have been numerous attempts to determine the total 40 K decay half-life in the last 78 years by two primary techniques—by physical direct counting experiments using Geiger-Müller and beta counters, ionization chambers and liquid scintillation counters; and by radioisotope age comparisons of rocks, minerals, and meteorites.

How many ppm of potassium are in potassium-40?

It makes up 0.012% (120 ppm) of the total amount of potassium found in nature. Potassium-40 is a rare example of an isotope that undergoes both types of beta decay.