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Grade 8 topics > Science > Flashcards

Science Flashcards

1
Q

Tectonic Plates

A

Since mantle flows, plates are always in slow motion
Shape of plates are revealed by geological events (volcanoes, earthquakes, mountains).

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2
Q

Lithosphere

A

Topmost mantle
Broken down into smaller pieces called tectonic plates

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3
Q

Continental Drift Evidence

A

Fossil Evidence: Fossils of plants and animals were found on separate continents
Climate evidence: Tropical plant fossils in cold areas and glaciers in warm areas.
Geological evidence: similar rocks found across the world

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4
Q

Continental Crust

A

Thicker and less dense than oceanic crust. Because of this it floats to the top, forming dry land.

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5
Q

Asthenosphere

A

Upper part of the mantle, semi-solid and flows slowly. It is below the lithosphere and convection is though to occur.

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6
Q

Oceanic Crust

A

Thinner, colder, and more dense than continental crust. It is also younger than continental crust.

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7
Q

Core

A

Liquid made of nickel; center of Earth and is very dense. It is responsible for Earth’s magnetic field.

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8
Q

Upper Mantle

A

Semi-solid
Causes tectonic plates to move

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9
Q

Lower Mantle

A

Magma, liquid, and located about outer core

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10
Q

Crust

A

Part of the land we walk on; surface

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11
Q

Ocean Trenches

A

Large, subduction.
The deepest spot of the planet.
Trenches = Subduction
Long, narrow depressions
Created when old crust is pushed beneath another plate

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12
Q

Sea Floor Spreading

A

Magma comes up from the crust and cools which creates land and mountains (underwater).
The farther away from the crack, the older the rocks are.

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13
Q

Mid-Ocean Ridges

A

Mountains found in oceans - deep rift valley in between the two ridges
Occur along divergent boundaries where new ocean floor is created as tectonic plates spread apart.

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14
Q

Atom

A

Atoms are too small to see with our eyes
Smallest part of molecule

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15
Q

Nucleus

A

A nucleus is a dense positively charged mass located in the center of the atom.
Atoms contain nucleuses

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16
Q

Subatomic Particles

A

Protons, Neutrons, Electrons

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17
Q

Atomic Number

A

protons in 1/11 of atom
Different for every atom
Atoms are natural
Positive charges are balanced by negative charges
Equal number of elements

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18
Q

Mass Number

A

Sum of Proton and Neutron
neutrons = mass - atomic

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19
Q

Chemical equations

A

Reactants = Products
To show that mass is preserved, there must be the same amount of elements on both sides.

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20
Q

Double Replacement (Chemical Reactions)

A

Two elements switched two spots

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21
Q

Decomposition (Chemical Reactions)

A

One compound turns into two separate compounds

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22
Q

Combustion (Chemical Reaction)

A

Anything that produces water and oxygen

23
Q

Synthesis (Chemical Reaction)

A

Two or more substances

24
Q

Pure Substance

A

Fixed composition
Elements
Compounds

25
Q

Mixtures

A

Have a variable compsition

26
Q

What is Newton’s First Law?

A

An object in motion tends to stay in motion and an object at rest tends to stay at rest until acted upon by an unbalanced force.

27
Q

What is Newton’s Second Law?

A

Force equals mass times acceleration (F=MA)

28
Q

What is Newton’s Third Law?

A

For every action there is a equal and opposite reaction.

29
Q

Inertia

A

The tendancy of an object to resist changes in it’s state of motion

30
Q

Acceleration

A

A measurement of when velocity changes

31
Q

Velocity

A

The rate of change of a position along a straight line with respect with time.

32
Q

Big Bang Theory

A

14 B years ago the material was compressed and then exploded into the universe

33
Q

What are the two confirmations of the Big Bang Theory?

A
  1. Moving Galaxies
  2. Cosmic Background Radiation (CBR)
34
Q

Solar Eclipse

A

Happens when the moon passes between the Sun and the Earth
Only during the day
Only during new moon phase
Does not occur often because of small shadow

35
Q

Lunar Eclipse

A

Earth blocks moon from Sun
Always full moon phase
Frequent because Earth has a large umbra

36
Q

Penumbra

A

Partial eclipse

37
Q

Umbra

A

Total eclipse

38
Q

Nebula

A

A cloud of dust, hydrogen, and helium gas
Created from similarity expansion
Over time, small particles came together then collided

39
Q

What are stars made of?

A

Hydrogen

40
Q

Protostar

A

Ball of gas and dust that is pulled together by gravity

41
Q

Main Sequence Star

A

Middle age
Longest age
All stars go through main sequence phase

42
Q

Spiral Galaxies

A

Have a bulge of older stars in the middle with arms of younger stars that spiral around

43
Q

Elliptical Galaxies

A

Shaped like spheres of flattened eggs. All the stars present are old.

44
Q

Irregular Galaxies

A

Faint galaxies with no regular shape. Smaller than most galaxies with fewer stars.

45
Q

Igneous Rock

A

Formed from cooling lava and hardening of magma
Granite, Basalt, obsidian

46
Q

Sedimentary Rock

A

Formed from compacting sediments
Makes up small percentage of Earth’s crust
Limestore, sandstone

47
Q

Metamorphic Rock

A

Form from extreme heat and pressure
Marble, slate

48
Q

Rock cycle

A

Rocks are created, changed, destroyed, and formed again
All rocks begin as igneous rocks
It can take millions of years for rocks to change

49
Q

Topographic Maps

A

The landforms and elevation of an area

50
Q

Index contour lines

A

Lines which have a measurement
Every 5 contour lines are index contour lines

51
Q

Landforms

A

Anything that physically impacts an area (mountains, hills, lakes, ponds, etc.)

52
Q

Elevation

A

How high an object is from sea level

53
Q

Contour interval

A

The change in elevation that each contour line represents.

Grade 8 topics (2 decks)

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