Big Idea 2 - Earth Science Review

Front

What is half-life?

Back

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

Front

If an element has a half-life of 20 million years, how much of it remains after 80 million years?

Back

6.25% (1/16th) of the original amount remains after 80 million years.

Front

What natural disaster is indicated by a sudden low tide revealing the ocean floor?

Back

A tsunami is likely to occur when there is a sudden low tide revealing the ocean floor.

Front

What does the Mid-Atlantic Ridge represent in terms of geological activity?

Back

The Mid-Atlantic Ridge is a divergent boundary where new oceanic crust is formed.

Front

Where is the youngest oceanic crust typically found?

Back

The youngest oceanic crust is found at the Mid-Atlantic Ridge, specifically at location C in diagrams of magnetic polarity.

Front

True or False: Only the continental crust moves around at Earth’s surface.

Back

False. Both continental and oceanic crusts move around at Earth’s surface.

Front

Where do deep-ocean trenches form?

Back

Deep-ocean trenches form at convergent boundaries where one tectonic plate is subducted beneath another.

Front

What is a convergent boundary?

Back

A convergent boundary is where two tectonic plates move towards each other, often causing one plate to be forced below the other.

Front

What is a tsunami?

Back

A tsunami is a series of ocean waves caused by large disturbances, such as earthquakes or volcanic eruptions, often resulting in significant coastal flooding.

Front

What is the significance of magnetic polarity in oceanic crust?

Back

Magnetic polarity in oceanic crust helps scientists understand the history of plate tectonics and the age of the ocean floor.