Age of Earth

Front

What is a fault?

Back

A fault is a break in Earth's crust caused by forces acting on the rocks on either side, and it is always younger than the rock layers it cuts through.

Front

What can scientists determine from studying fossils?

Back

Scientists can determine how the environment changed over time, how organisms (plants and animals) evolved, and the age of rock layers, but they cannot determine how gravity changed over time.

Front

What is radioactive decay?

Back

Radioactive decay is the breakdown of radioactive elements over time, where the atoms of one element break down to form atoms of another element.

Front

Is radioactive dating qualitative or quantitative?

Back

Radioactive dating is a quantitative way of collecting data.

Front

What does finding a marine fossil in the desert indicate?

Back

It indicates that the area was once a body of water.

Front

What is the law of superposition?

Back

The law of superposition states that in undisturbed sedimentary rock layers, the oldest layers are at the bottom and the youngest layers are at the top.

Front

What is an index fossil?

Back

An index fossil is a fossil that is used to define and identify a particular time period in the geological time scale.

Front

What is half-life?

Back

Half-life is the time required for half of the radioactive atoms in a sample to decay.

Front

What is relative age?

Back

Relative age is the age of an object in relation to the ages of other objects.

Front

What is the significance of sedimentary rock layers?

Back

Sedimentary rock layers provide important information about the Earth's history, including past environments and the organisms that lived during those times.