# Air Test Review

## Vocab

Force-a push or a pull exerted on an object

Magnitude-strength of force in newtons (N)

Balanced Forces-when forces that act on an object are equal in strength and opposite in direction, net force = 0 N, no change in motion

Unbalanced Forces-when forces acting on an object are NOT equal in strength or opposite in direction, there is a net force causing object to speed up, slow down, or change directions

Net Force-the combination of all the forces acting on an object

Interia-the tendency of an object to resist a change in motion

Relative Motion-the motion of an object appears differently when viewed from different places or compared to different things

Frame of Reference-place from which you view motion

Refernce Point-the object you are comparing the moving object to

Gravity-a force that pulls all objects on Earth towards the center of the Earth

Tension-a force transmitted through string, rope, or wire when it is pulled tight by forces acting on both ends

Friction-a force that opposes motion when two surfaces are in contact

Air resistance-a force that acts on objects as they travel through air

Normal force-a support force exerted upon objects at a right angle (perpendicular) to the surface it touches

Applied force- a push or pull exerted on an object by a person or another object

## Newtons Laws

Newton's first law of motion states that an object at rest will remain at rest, and a object moving at a constant velocity will continue at a constant velocity, unless acted upon by a unbalanced force

Newton's second law states that acceleration depends on the object's mass and on the net force acting on the object

Acceleration= Net force/Mass

Newton's third law states that if one object exerts a force on another object, then the second object exerts a force of an equal strength in teh opposite directionon the first object.

Acceleration is measured by meters per second per second (m/s^2), and mass is measured in kilograms (kg). Force is measured in kilograms times meter per second per second (kgxm/s^2)

## Intro

Three things that increase as you move from the crust to the ineer core are pressure, temperature, and density. Two things that helped scientists learn about the composition of the Earth are magnetism and meteors. Earth has an iron core which is magnetic and meteors are made of the same material that the Earth is made of.

## The Structure of Earth

The Earth is made up of 3 main layers and 4 majors layers with a couple extra. The 3 main layers contain of the crust, mantle, and core. The 4 major layers are the crust, mantle, outer core, and inner core. There is also the lithosphere, asthenosphere , oceanic crust, and the continental crust.

## Composition of the Earth

Crust- Thinnet layer, least dense layer, composed of silicon and oxygen, contains igneous, metamorphic, and sedimentary rocks, thinnest under oceans

Mantle- Composed of silicon, oxygen, and magnesium, makes up 80% of Earth's volume, largest layer, contains a layer called the asthenosphere

Outer core- compose do liquid iron and nickel, s-waves will not travel through this layer, second hottest layer up to 5000 degrees C

## Alfred Wegener

Alfred Wegener was the first man to believe that the continents had once been together and since then had drifted apart. His hypothesis was that the continents were once a single landmass that has since then drifted apart. This "supercontinent" was named Pangaea meaning "all lands." He used the shape of the continents, evidence of climate change, fossils, and land features to support his theory. He used he evidence from his fossils by finding that the same type of organism is found on many different continents in which that organism might not have survived. Glossopteries, a type of fern, is found on many continents today. He used climate as his evidence by finding that tropical plants and animals fossils are found in cold places like Antarctica, glacial grooves, and are found in South Africa. He used land features as his evidence by that mountain chains in Africa and South America line up and that coal deposits in Europe and North America that line up as well. The reason that no one would beileve him was because that he couldn't explain what force or forces moved the continents

## Vocab

Lithosphere- a rigid layer made up of the uppermost part of the mantle and the crust

Asthenosphere- the soft layer of the mantle on which the lithosphere floats

Density- the amount of mass in a given space; mass per unit volume

Convection currents- the movement of a fluid, caused by the differences in the temperatures, that transfers heat fro, one part of the fluid to another

Continental drift- the hypothesis that the continents slowly move across Earth's surface

Harry Hess- an American geologists that's studied the mid-ocean ridge or MOR

Rift Valley- a deep valley that forms where 2 plates move apart; its created by divergent plate boundaries

Scientific Theory- a well tested concept that explained a wide range of observation

Outer core- a layer of molten iron and nickel at the center of the Earth

Inner core- a dense sphere of solid iron and nickel that surround the inner core of the Earth

Crust- a layer of solid rock that forms Earth's outer skin

Mantle- the layer of hot solid material between Earth's crust and core

Plate- a section of the lithosphere that slowly moves over the asthenosphere, carrying pieces of the continental and oceanic crust

Plate Theory- pieces of Earth's lithosphere are in slow constant motion, driven by convection currents in the mantle

Fault- breaks in the Earth's crust where rocks have slipped past each other, where earthquakes occur

Divergent boundary- where 2 plates move apart

Convergent boundary- where 2 plates come together or converge

Transform boundary- where 2 plates slip past each other, moving in opposite direction

Mid- ocean ridge- an undersea mountain chain where new ocean floor is produced at a divergent plate boundary

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

Sea-floor spreading- the process by which molten material continually adds new material to the ocean floor that was discovered by Harry Hess

Deep-ocean trench- a deep valley along the ocean floor beneath which oceanic crust sinks slowly toward the mantle

Subduction- the process by which ocean floor sinks beneath a deep-ocean trench and back into the mantle at a convergent plate boundary

## Divergent plate boundary

A divergent boundary is a constructive boundary, meaning that's it adds crust instead of destroying it. Mid-ocean ridges with Rift Valleys surrounded by 2 ridges are the formations that are associated with the divergent boundary. Divergent boundaries uses the process of sea-floor spreading to create new crust. Examples of divergent are the Red Sea and the Great Rift Valkey of East Africa.

## Convergent plate boundary

Continental-Continental~

This type of convergent plate boundary destroys crust. Mountain ranges are the formation that is associated with the continental-continental convergent plate boundary. This plate makes mountain ranges. An example of the continental-continental convergent plate boundary is the Himalayas (Mt. Everest).

Continental-Oceanic ~

This type of plate boundary also destroys crust. Deep-ocean trenchs and volcanic arcs are associated with continental-oceanic convergent plate boundary. Subduction usually occurs at the continental-oceanic convergent plate boundary. Some example of continental-oceanic convergent plate boundary are the Andes Mts. and the Chile Peru deep sea trench

Oceanic-Oceanic ~

This type of plate boundary destroys the Earth's crust. Trenchs with island arc or underwater Volcanic Arc are associated with the oceanic-oceanic convergent plate boundary. Subduction occurs at the oceanic-oceanic convergent plate boundary. Som examples of the oceanic-oceanic convergent plate boundary are the Japan Trench and the Mariana Trench

## Transform plate boundary

This plate doesn't create or destroy the Earth's crust. Faults usually are associated with transform plate boundaries. The motion at this boundary are when 2 plates slide past each other. An example of a transform plate boundary is then San Andres Fault.
Three ways that a can contribute to the movement of plates are

Convection currents

Slab pull- gravity pulls the ends of the plates at subduction zones and drags them toward the center of the Earth

Ridge push- new crust is formed at a divergent boundary

## How do convection currents work

Convection currents work because the outer core heats the material in the lower mantle, that the material becomes less dense and rises, and when it cools, it becomes more dense and sinks toward the outer core and the cycle repeats over and over again.