Fossil Dating

Question 1

What is fossil dating?

Answer 1

The process whereby the age of fossils is determined

Question 2

What two methods can be used to determine the age of fossils?

Answer 2

Radiometric dating

Relative dating

Question 3

What is radiometric dating?

Answer 3

A method of deducing the age of fossils that is based on radioactivity

Question 4

Which elements have radioactive isotopes?

Answer 4

Uranium
Potassium
Carbon

Question 5

What is a radioactive isotope?

Answer 5

A substance , the atoms of which have a different number of neutrons to other atoms of the same element
The substance in this form is radioactive

Question 6

What is a radioactive substance?

Answer 6

A substance which decays into a non-radioactive isotope of another element by releasing nuclear particles

Question 7

What is a half-life?

Answer 7

It is the rate of decay of a radioactive isotope

Question 8

What is the rate of decay of an isotope?

Answer 8

The amount of time it takes to break down half of the mass of the radioactive material to its decay product

Question 9

What are the two methods of radiometric dating?

Answer 9

Direct

Indirect

Question 10

What is the direct method of radiometric dating?

Answer 10

The radioactive decay of the actual fossil is measured

Question 11

What kind of fossils is the direct method used for?

Answer 11

Fossils younger than 50 000 years old

Question 12

How is the age of fossils younger than 50 000 years old measured?

Answer 12

Through carbon dating

Question 13

How does carbon dating work?

Answer 13

All organisms contain both Carbon fourteen and Carbon twelve
Carbon twelve is a stable isotope
Carbon fourteen is a radioactive isotope
Both isotopes are present in living organisms
All living organisms have the same ratio of carbon fourteen o carbon twelve
By measuring the current amount of carbon fourteen and comparing it to the ratio, you can tell the age of the fossil

Question 14

What is the indirect method of radiometric dating?

Answer 14

The age of the rocks surrounding the fossil is measured

Question 15

When is the indirect radiometric method used?

Answer 15

When fossils are older than 50 000 years old

Question 16

How is the age of the rocks surrounding a fossil determined?

Answer 16

The amount of the original isotopes as well as the amount of the decay product in the rocks sample is measured
It is now possible to determine the age of the rock

Question 17

What is relative dating?

Answer 17

It is an estimate of a fossil’s age based on the surrounding layers of rock

Question 18

What is the method used for relative dating?

Answer 18

Palaeontologists study the sedimentary layers above and below a fossil

Question 19

What is the theory behind relative dating?

Answer 19

The oldest fossils will be lower down

Question 20

Why is relative dating not the preferred method for determining the age of fossils?

Answer 20

It is not a very accurate form of dating

Question 21

What is inference?

Answer 21

Deductive reasoning

Question 22

What is deductive reasoning?

Answer 22

It is when scientists use logical reasoning to make deductions and conclusions from the observations and evidence that is collected

Question 23

What is deductive reasoning used for?

Answer 23

To understand fossils that are discovered and the history of life on earth