Half Life Calculator

Find out the age of any organic or mineral sample

Half-life by definition is the time required for a substance to reduce to half of its initial value. It is commonly used to describe how fast unstable atoms undergo radioactive decay. With this tool, you can differentiate between half-life, decay constant, and the exponential decay process. From your results, you can find out the age of organic or mineral samples, and how long to store radioactive waste.

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What is half-life?
Half-life by definition is the time required for a substance to reduce to half of its initial value. It is commonly used to describe how fast, unstable atoms undergo radioactive decay. While radioactive decay is a random process, it’s easy to make predictions when you have considerable numbers of nuclei.
The half-life of a substance can also to tell you how long stable atoms can survive. This can be useful for finding out the age of various things based on their composition . Beyond that, half-life can even be applied to how certain drugs or chemicals act within the human body.
All you need is some relevant information about the objects, substances, or chemicals you are studying. Then, you can find out the decay constant or exponential decay process.
Uses for the half-life calculator
The half-life calculator is very straightforward to use. You can use it to figure out the age of any organic matter, rocks, or artifacts. Beyond that, you can use this calculator to decide how long to store radioactive waste. The general rule is to hold on to the waste for ten times the half-life.
Carbon dating
Finding out the age of an organism requires carbon dating . All living things have carbon-14 in them as it is formed in the atmosphere. Plants absorb it through air and animals eat those plants. Through the food chain, carbon-14 reaches all living organisms.
When something dies, it no longer absorbs carbon-14. Eventually, the carbon-14 will decay into nitrogen. So by figuring out how much of the carbon-14 has transformed, you can find how old the organic matter is.
To add some perspective, carbon-14 has a half-life of 5,730 years. You can find the age of old relics like bone, cloth, and ancient scrolls by measuring the carbon content.
Mineral dating
Alternatively, you can calculate the age of rocks and minerals through uranium-lead dating . Lead-206 and lead-207 are formed in rocks from series of uranium isotope reactions. The amount of lead in a rock increases as the rock ages.
The age of the sample depends on which uranium isotope you are dealing with. Uranium-238 to lead-206 decay series has a half-life of over 4 billion years. Meanwhile, uranium-235 to lead-206 half-life is about 700 million years.
There are some additional methods to date inorganic materials such as potassium-argon dating and rubidium-strontium dating. These elements have a half-life of 1 billion years to 50 billion years of existence, respectively.
How to use the half-life calculator
The half-life calculator is very straightforward to use provided you know with certainty some of the variables required for the calculations.
First, you may choose to calculate for half-life , mean lifetime , decay constant , or the decay process (half life) . You can make your selection using the tabs at the top of the calculator.
Half-life (t½) , mean lifetime (t) , and decay constant : Here you must include one value, and the calculator will provide you with the other two.
To get your results, you should hit calculate . To try another calculation you must first reset the calculator before inputting new values.
Decay process : Using the second tab you will be presented with four information inputs; the quantity remains N(t) , initial quantity N0 , time t , and half-life t½ . Here you must include three of the four variables.
To find the missing variable you should choose to calculate . Before beginning any new calculations, make sure to hit the reset button.
The exponential decay process
Though there are numerous formulas, this calculator defines the exponential decay process with the following equation:
N(t)= N0 (½) t/t½
  • N(t) refers to the quantity that remains and has not decayed after a time- t,
  • N0 refers to the initial quantity of the substance that will decay,
  • relates to the half-life of the decaying quantity
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