chapter 17- science test

1. megnetometer D 2. iron B 3. isochron A 4. new oceanic crust C

1. device that detects small change in magnetic fields 2.minerals containing this act like small compass needles and record the orientation of earths magnetic field at the time of their formation 3. this type of line connects points on the map that have the same age 4. each cycle of spreading and magma intrusion along an ocean ridge results in the formation of this options a- isochron b- iron c- new ocean crust d- magnetometer

The formation of the earth has never stayed the same and is always changing. There have been many theories made about the land layout. For example, the article says in tens of millions, american and euro- African continates will come smashing together and in 250 million years the continents will become one big land mass again, pangea ultima

Give a summary about the movement of the continents of the earth

Huge pieces of crust in ridged upper mantle that fits together at their edges like puzzle pieces

What are tectonic plates made of

sound navigation and ranging

What does SONAR stand for?

Pangaea is a hypothetical super continent that included all current land masses, believed to have been in existence before the continents broke apart over time

define Pangaea

a theory that proposed earths continents had once been joined as a single landmass that broke apart and sent the continents a drift

define continental drift

the remains of a prehistoric organism

define fossil

speed of sound in water x time for a sound to return to the boat

formula to calculate the distance to seafloor

ocean ridges sinking into trenches

new crust forms at... and old ocean crust is...

magnetic field normal polarity reversed polarity isochron younger older

options: isochron, older, magnetic field, reversed polarity, normal polarity, younger earth's __________ has changed over time. A field with the same orientation as today's field is said to have _______. A field that os opposite he present field has __________. Magneometers have been used to measure the ocean floor's magnetic field. Magnetic data of the ocean floor is ____________ near ocean ridges and_________ near deep sea trenches

1. magma is forced upward toward the crust 2. magma fills the gap that is created 3.magma hardens to form new crust

order 1-3 for sea floor spreading - magma fills the gap that is created - magma hardens to form new crust - magma is forced upward toward the crust

f, seafloor spreading

t of f- the theory of continental drift states that new oceanic crust is formed at ocean ridges and destoryed at deep sea trenches

true

t or f earthquake activity and volcanism are common along ocean ridges

false, magnetic reversal

t or f- an isochron is a change in earths magnetic field

f, midocean ridges

t or f- deep sea trenches are vast , underwater mountain chains

True

t or f- maps made from sonar and magnetometer data led to the discovery of mid ocean ridges and deep sea trenches

f, younger

t or f- rock samples taken near ocean ridges are older than rock samples taken near deepsea trenches

True

t or f- sonar uses sound waves to measure water depth

f, mid ocean ridge

t or f- the magnetic patterns on either side of a deep sea trench are mirror images of eachother

f, increases

t or f- the thickness of the ocean floor decreases w distance from an ocean ridge

true

t or f- theory of seafloor spreading explains that earths continents move because they ride atop ocean crust as it moves away from ocean ridges

came up w the idea of seafloor spreading he came up with this when he was on a ship and wanted to know what was below him

what did harry hess come up w

Marianas Trench

what is the biggest trench

Convection- when hot things rise it should be moving up into the other water bc it's less hot/dense cools down and causes the color water to fall back down bc it's cooler and much less dense bc hot magma in the mantle rises to the crust, cools, causing it to gain density then it comes back down getting hotter and gains density

what process was shown in our convection lab how did the coloring move from the 50 mL beaker, why what happened w more ice in the big beaker, why How does this lab relate to the mantle of the earth

Theory of Pangea- continents were all joined at one time in Earth's history, making a supercontinent. A supercontinent is a giant landmass made up of many or all continents. proof- rock, fossil and climate evidence Rock- there rock in mountins were in europe- if they had them in different places that means they were once the same place Fossil- similar fossils of animals and plants were found on widely spread continates Climatic- glossopters were found on many parts of the earth He was rejected because he didn't answer 2 important questions to explain his theory 2 qs- the force that caused the movement & how continents could move through solids In the 1960s after advanced tech, his theory was reconsidered

what was Alfred Wegener's theory, how did he try to prove it, tell the evidence, why was it rejected, what were the 2 questions, was was revealed in the 1960s

ridge without a trench

you can't have a _______ without a _______