8th grade science vocab terms Flashcards
opposite poles of a magnet do this
attract
the range of wavelengths or frequencies over which electromagnetic radiation extends (includes gamma, x-ray, UV, visible light, infrared, microwave, and radio waves)
Electromagnetic spectrum
analyzed preserved remains, traces of animals & plants, and microorganisms to reconstruct the history of life on Earth
fossil record
generated when a bar magnet is moved through a wire coil
electric current
uses curved mirrors, largest optical telescopes in the world
reflecting telescope
empty space that only electromagnetic waves can travel through
vacuum
part of the earth’s crust that is thick but not as dense as oceanic crust
continental crust
formed when oceanic crust subducts under continental crust at subduction zones (Convergence-Oceanic subduction)
volcanic mountain range
also known as artificial selection, is a process used by humans to develop new organisms with desirable characteristics.
selective breeding
change in direction of waves that occurs when waves travel from one medium to another.
refraction
formed in the ocean when magma rises up, erupts, cools and solidifies and pushes the sea-floor outwards.
mid ocean ridge
Long, narrow ditches in the Earth’s crust when 2 or more oceanic plates converge and one subducts under the other.
trench
a process that occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity.
sea floor spreading
waves that don’t require a medium.
electromagnetic wave
bouncing back of waves.
reflection
thinnest layer of the Earth.
crust
68% of Earth’s mass, movement in this layer causes the movement of the continents (convection currents)
mantle
uses mechanical energy to produce electricity.
generator
type of mechanical wave where the energy runs at right angles (perpendicular) to the wave.
transverse wave
during the first and third quarters of the Moon, Moon and Sun are at right angles to each other.
neap tide
occurs whenever there is a full or new moon, Sun and Moon must either be in a straight line on the same side of Earth, or they must be on opposite sides of Earth, gravity causes very high and very low tides
spring tide
largely metallic and mainly iron, the outer core is liquid and responsible for generating the Earth’s magnetic field
outer core
when one plate dives under another plate due to it being more dense.
subduction
most dense layer of Earth, SOLID DUE TO IMMENSE PRESSURE. This is also why it is the hottest layer.
inner core
occurs when two plates collide together. Form mountains, island arcs, volcanos. and ocean trenches.
convergent plate boundary
occurs when an object moves towards the observer
blueshift
plates that are moving apart. Form mid ocean ridges and continental drift zones
divergent plate boundary
For every action there is an equal but opposite reaction
Newton’s 3rd law
force that opposes motion
friction
Structures that have “lost” their original use
Vestigial structure
simply a coil of wire wrapped around an iron core connected to an electric current producing a magnetic field.
electromagnet
Two ways to increase strength of electromagnet
1) increase current 2) increase number of coils
Age of a fossil by comparing it to the fossils around it, generally which is older and which is younger- no exact numbers.
Relative age
similar structure, different function/job
Homologous structure
different structure, similar function/job
analogous structure
also known as selective breeding, is a process used by humans to develop new organisms with desirable characteristics.
artificial selection
uses refracting lenses to see things within our solar system.
refracting telescope
one complete wave cycle; usually measured crest to crest or trough to trough
wavelength
any characteristic or trait that allows an organism to survive
adaptation
lowest point of a wave
trough
highest part of a wave
crest
proposed the theory of Continental Drift which became the basis for today’s modern plate tectonic theory.
Alfred Wegener
a break in the rocks that make up the Earth’s crust, along which rocks on either side have moved past each other.
fault
when plates slide past each other.
transform plate boundary
rides on plates and is more dense but less thick than continental crust.
oceanic crust
speed and direction
velocity
can be moved through a wire coil to induce an electric current
bar magnet
Proposed the process of natural selection based on observations made during his travels.
Charles Darwin
Describes how force and mass affects acceleration (f=ma)
Newton’s 2nd law of motion
below lithosphere and part of upper mantle, behaves plastically and flexible, hot solid and malleable
Asthenosphere
part of the crust and uppermost mantle, floats on top of the asthenosphere, brittle and rigid
Lithosphere
process by which living things with beneficial traits produce more offspring, so their traits become more common over time.
Natural Selection
type of mechanical wave in which the energy flows parallel to the wave. (rarefaction, compression)
Longitudinal wave
occurs when waves bend around small obstacles or openings.
Diffraction
when water reaches the lowest point (twice a day)
low tide
when water reaches the highest point (twice a day)
high tide
An unmanned spacecraft designed to explore the solar system & transmit data back to earth, uses radio waves
space probe
used for navigation systems, such as the Global Positioning System (GPS)
navigational satellites
receive and send signals for telephone, television, or other types of communications.
communication satellites
Take pictures of Earth’s surface for military or scientific purposes.
imaging satellites
body of matter
medium
waves that require a medium to travel in. (sound waves, water waves, etc.)
mechanical wave
rocks that have been changed due to temperature and pressure increases.
metamorphic
(primary) First to be detected by seismometer, Longitudinal motion, refract/bend when changing earth’s layers- faster in denser material, FASTEST MOVING WAVES, Travel fastest through SOLID inner core
P-wave
(secondary) Half as fast a P-waves, Arrive second at seismographs, Transverse motion, Can only travel through solids
S-wave
distance of a wave measured from the equilibrium point (how high or low the wave goes)
amplitude
Number of vibrations per unit time, measured in Hertz (Hz), determines pitch in sound waves, determines color in light waves.
frequency
Device used to separate white light from a star into a very wide spectrum of color, Gives information about wavelength, frequency, & energy, HELPS DETERMINE CHEMICAL COMPOSITION OF STARS
spectroscope
when energy of a wave is not transferred though or reflected by the medium.
absorption
when waves pass through a point or a medium.
transmission
this is what like poles on a magnet do.
repel
takes electrical energy and converts it to mechanical energy/motion.
motor
amount of matter in an object
mass
is formed through the cooling and solidification of magma or lava. Can be “intrusive”(cools inside Earth) OR “extrusive” (outside)
igneous rock
physical traits or characteristics
phenotype
rocks formed by deposition and cementation in layers. Most fossils are found in this type of rock.
sedimentary
force of gravity acting on an object.
weight
is the theory that the Earth’s continents have moved over geologic time relative to each other, thus appearing to have “drifted” across the ocean bed.
continental drift
Uses radioactive materials to determine the exact ages of rocks & fossils in each layer (radiometric dating)
absolute
highest point of a wave
crest
change in speed over time
acceleration
An object at rest stays at rest and an object in motion stays in motion UNLESS acted on by an outside force.
Newton’s 1st law
occurs when an object is moving away from an observer.
Redshift
