Absolute Age Dating

Absolute-Age
Dating

Using elements to determine numerical age.

What is Absolute-Age Dating?

Using Radioactive Elements to Determine Age

Scientists can use very small amounts of radioactive elements to determine how old an object is. This works in anything from dead trees to rocks and fossils!

An element is "radioactive" when the particles are unstable and release energy in the form of radiation.

Drag and Drop

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dating is when scientists use radioactive elements to figure out how old an object is.

Drag these tiles and drop them in the correct blank above

Absolute Age

Relative Age

Radio Station

Approximate Age

Multiple Choice

When particles of an element become unstable and release energy in the form of radiation, that element is said to be:

• Radioactive

• Relative

• On Fire

• Convection

Each radioactive element has a different rate of "decay". This length of time is referred to as the Half-Life of the element.

Half-life: The amount of time it takes for half of the radioactive atoms to decay.

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Measuring Radioactive Decay

Each ring represents 1 year in the tree's life. Counting the number of rings will give you the amount of years the tree was alive.

Tree Rings

The amount of time it takes for half of the radioactive atoms in an object to decay. Knowing how much radioactive material is still left in an object will tell you how old the object is.

​​Half-Life

Multiple Choice

The amount of time it takes for half of the particles of an element to decay is called:

• Absolute Age

• Half-Life

• Radioactivity

​When the object forms, this is when there is 100% of the radioactive elements in an object.

Starting Point

​The amount of time it takes for half of the radioactive atoms to decay.

1st Half-Life

50% of the radioactive element is left. After a second half-life, we are left with 25%.

​​2nd Half-Life

25% is left from the original amount. After a third half-life, we are left with 12.5%.

​​3rd Half-Life

Hotspot

Which of the logs have experienced 2 half-lifes?

Different elements have different half-lives. Some elements decay very quickly and some decay very, very slowly.

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Different Elements

No Carbon-14 has started to decay yet.

How old is this log?

​​Starting Point

​After 1 half-life, 50% of the Carbon-14 is left.

How old is this log?

​​1st Half-Life

​After 2 half-life, 25% of the Carbon-14 is left

How old is this log?

​​​​2nd Half-Life

After 3 half-life, 12.5% of the Carbon-14 is left

How old is this log?

​​​​3rd Half-Life

Carbon-14 - Half-life: 6,000 years

Multiple Choice

How much of the original radioactive element is remaining after 2 half-lives?

• 100%

• 75%

• 50%

• 25%

Multiple Choice

If there is 12.5% of the radioactive element left in an object, how many half-lives has it experienced?

• 1

• 2

• 3

• 4

Multiple Choice

The half-life for a radioactive particle is 2,500 years. How old is an object that only has 50% of that particle remaining?

• 1,250 years

• 2,500 years

• 5,000 years

• 10,000 years