WorksheetsSeafloor Spreading
Total questions: 20
Worksheet time: 11mins
Select all that apply:
Which technological advances in the 1940s and 1950s changed how scientists viewed the ocean floor?
sonar
magnetometer
spectrograph
underwater telescope
A device that can detect small changes in magnetic fields is called a(n)
sonar
magnetometer
spectrograph
underwater telescope
What sediment evidence led to the discovery of seafloor spreading?
Layers of sediments on the ocean floor are much thinner than layers of sediment on continents.
Layers of sediments on the ocean floor are much heavier than layers of sediment on continents.
Layers of sediments on the ocean floor are much thicker than layers of sediment on continents.
What happens when the flow in the outer core changes, and Earth's magnetic field changes direction?
magnetic symmetry
paleomagnetism
core reversal
magnetic reversal
A magnetic field that has the same orientation as Earth's present field has _______________ polarity.
good
normal
abnormal
retrograde
A magnetic field that is opposite to the present field has ______________ polarity.
normal
reversed
retrograde
backward
What device can detect small changes in magnetic fields?
magnetometer
spectrograph
seismometer
The study of the history of Earth's magnetic field is called...
Geology
Biology
Paleomagnetism
Astronomy
Select all that apply:
Which major ocean-floor features were discovered by data collected by sonar and magnetometers?
deep-sea trenches
continental shelves
ocean ridges
What did scientists learn by matching magnetic patterns on the seafloor with known patterns of magnetic reversals on land?
the temperature of the ocean floor
the depth of the ocean floor
the age of the ocean floor
Select all that apply:
What rock evidence led to the discovery of seafloor spreading?
The age of oceanic crust consistently increases with distance from a ridge.
The youngest oceanic rocks are much older than the youngest continental rocks.
The thickness of ocean sediments increases with distance from an ocean ridge.
The oldest oceanic rocks are much younger than the oldest continental rocks.
The age of oceanic crust consistently decreases with distance from a ridge.
An imaginary line on a map that shows points that have the same age is called a(n)
isotope
isometric
isochron
equator
The theory that explains how new oceanic crust is formed at ocean ridges, slowly moves away from ocean ridges, and is destroyed at deep-sea trenches is called
Tectonic Theory
Plate Theory
Gap Theory
Seafloor Spreading
Select all that apply:
What is true of magnetic fields?
A magnetic field with reversed polarity has the opposite orientation as Earth's present field.
A magnetic field with reversed polarity is caused by the flow of materials in the inner core.
A magnetic field with normal polarity does not change over time.
A magnetic field with normal polarity has the same orientation as Earth's present field.
What is an imaginary line on a map that shows points that have the same age?
isotherm
isobar
contour line
isochron
What theory explains how new oceanic crust is formed at ocean ridges, slowly moves away from ocean ridges, and is destroyed at deep-sea trenches?
continental drift
seafloor spreading
plate tectonics
Studies of the seafloor provided evidence that the ocean floor is
flat
unchanging
geologically young
New oceanic crust forms as _________________ rises at ridges and solidifies.
gas
ice
magma
water
As new oceanic crust forms, the older crust moves...
upward towards the surface
closer to the ridges
away from the ridges
Seafloor spreading can be compared to a(n)
elevator
conveyor belt
stairs
airplane
