Ocean Hw2

Homework 2

CC 1.7 Describe how the half-life of radioactive materials can be used to determine the age of a rock through radiometric age dating.

Certain isotopes of elements spontaneously change/decay to other elements and this happens at a certain rate that can be described by half-life, which is the time it takes for one half of the original atoms to decay.

CC 2.1 Cite the lines of evidence Alfred Wegener used to support his idea of continental drift. Why did scientists of the time doubt that continents had drifted?

Evidence for continental drift

• Puzzle like fit of continents

• Distribution of fossils

• Distribution of rocks

• Glacial/Climate info

• Magnetic directions recorded in rocks

It is because of Fossils.Fossils of the aquatic reptile Mesosaurus, which lived about 250 million years ago, are found only in South America and Africa. The limited distribution of Mesosaurus fossils suggest that these two continents were once joined.

CC 2.2 #1. 3. 4 Describe Earth’s magnetic field, including how it has changed through time.

In Earth’s magnetic field, the invisible lines of magnetic force that originate within Earth and travel out into space resemble the magnetic field produced by a large bar magnet.3 Similar to Earth’s magnetic field, the ends of a bar magnet have opposite polarities (labeled either + and – or N for north and S for south) that cause magnetic objects to align parallel to its magnetic field.

Describe sea floor spreading and why it was an important piece.

Seafloor spreading is a process that occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge. And because Seafloor spreading helps explain continental drift in the theory of plate tectonics.

Why does a map of worldwide earthquakes closely match the locations of worldwide plate

boundaries?

Most earthquakes occur along the edge of the oceanic and continental plates, so a map of earthquakes matches the...