Age of Earth (FL SC.7.E.6.3 & E.6.4)

Front

What are fossils?

Back

Fossils are the preserved remains or traces of ancient organisms, providing evidence of past life forms and environments.

Front

Why are fossils important for understanding Earth's history?

Back

They provide evidence of past life forms and environments.

Front

What is the Law of Superposition?

Back

The Law of Superposition states that in undisturbed rock layers, the oldest layers are at the bottom and the youngest layers are at the top.

Front

How does the Law of Superposition help in dating rock layers?

Back

It helps scientists determine the relative ages of rock layers based on their position.

Front

What can marine fossils in a mountain region indicate?

Back

They suggest that the region was once underwater.

Front

What is radiometric dating?

Back

Radiometric dating is a method used to determine the age of rocks and fossils by measuring the decay of radioactive isotopes.

Front

What is half-life in the context of radiometric dating?

Back

Half-life is the time it takes for half of a radioactive substance to decay.

Front

If a rock sample contains 25% of its original uranium-238, how old is it if uranium-238 has a half-life of 4.5 billion years?

Back

The rock is 2.25 billion years old.

Front

What does the presence of basalt on top of other rock layers indicate?

Back

It indicates that the basalt layer is younger than the layers beneath it.

Front

What is the significance of finding the same sequence of rock layers in different locations?

Back

It suggests that the locations may have experienced similar geological processes.