Seafloor Spreading

Question 1

a device that bounces sound waves off underwater objects and then records the echoes of these sound waves,

Answer 1

SONAR (Sound Navigation Ranging)

Question 2

in the seafloor was normal at mid- ocean ridges but reversed in symmetrical patterns away from the ridge center. This normal and reversed pattern continues across the seafloor.

Answer 2

Magnetic polarity

Question 3

that were attached to ships scientists discovered a lot about the magnetic properties of the seafloor.

Answer 3

Magnetometer

Question 4

seafloor has different features

Answer 4

Continental shelf, continental slope, abyssal plain, mid ocean ridges, seamount, trench

Question 5

This crust eventually subducts at the deep ocean and melts back into the mantle

Answer 5

Trenches

Question 6

the magma moves up from the mantle and erupts as pillow lava. This forms new

Answer 6

Seafloor spreading
Oceanic crust

Question 7

He explained how the convection currents in the Earth’s interior makes the seafloor spread.

Answer 7

Harry Hess 1960

Question 8

The following are three evidence that support the idea that seafloor is continuously spreading.

Answer 8

Evidence from molten materials
Evidence from magnetic strip
Evidence from drilling sample

Question 9

rocks shaped like pillows (rock pillows) show that molten materials have erupted again and again from cracks along the midocean ridge and cooled quickly

Answer 9

Evidence from molten materials

Question 10

strip-rocks that make up the ocean floor lie in a pattern of magnetized stripes which hold a record of the reversals in the magnetic field

Answer 10

Evidence from magnetic strip

Question 11

core samples from the ocean floor show that older rocks are found farther from the ridge; youngest rocks are in the mid-ocean ridge

Answer 11

Evidence from drilling sample

Question 12

carries heat from the molten materials in the mantle and core towards the lithosphere.

Answer 12

Convection current