8th Grade Science Vocabulary Flashcards

These flashcards cover key vocabulary terms and their definitions relevant to 8th grade physical, earth, and life sciences.

force

A push or pull exerted on an object.

magnetic force

The attraction or repulsion between magnetic poles.

electrical force

A force that one charge exerts on another; like charges repel; opposites attract.

gravitational force

An attractive force between any two objects.

electric field

A region around a charged object where the object's electric force is exerted on other charged objects.

magnetic field

The region around a magnet where the magnetic force is exerted.

gravitational field

The region of space surrounding a body in which another body experiences a force of gravitational attraction.

weight

A measure of the gravitational force exerted on an object.

mass

The amount of matter in an object.

motion

An object's change in position relative to a reference point.

reference point

A place or object used for comparison to determine an object’s motion.

net force

The overall force on an object when all the individual forces acting on it are combined.

force diagram

A diagram that shows the forces acting on an object as arrows that indicate the magnitude and direction of the force.

balanced forces

Forces acting on an object that combine to a net force of zero.

gravitational potential energy

Potential energy of an object that depends on its mass and height above Earth.

elastic potential energy

The potential energy of an object that is stretched or compressed.

chemical potential energy

The energy stored in the chemical bonds of a substance.

electrical potential energy

Potential energy associated with an object’s charge.

magnetic potential energy

Stored energy due to the relative position of magnetic objects.

kinetic energy

Energy of motion.

potential energy

Energy that is stored.

seismic waves

Vibrations that travel through Earth carrying the energy released during an earthquake.

inner core

A dense sphere of pressurized solid iron and nickel at the very center of Earth.

outer core

A layer of molten (liquid) iron and nickel that surrounds the inner core of Earth.

mantle

The layer of Earth between the crust and core.

lower mantle

The lowest portion of mantle, a zone of rigid rock.

crust

The thin and solid outermost layer of the Earth.

convection currents

The movement of a fluid, caused by differences in temperature, that transfers heat from one part of the fluid to another.

planetary differentiation

The process in which more dense materials of a planet sink to the center, while less dense materials stay on the surface.

tectonic plates

A block of lithosphere that consists of the crust and the rigid, outermost part of the mantle that move by convection currents.

continental drift

The gradual movement of the continents across the Earth's surface.

divergent boundary

The boundary between two tectonic plates that are moving away from each other.

convergent boundary

A tectonic plate boundary where two plates collide or come together.

transform boundary

The boundary between tectonic plates that are sliding past each other.

sea-floor spreading

The process by which new ocean floor forms as magma rises from the mantle toward the surface and cools then solidifies.

subduction zone

Where an oceanic plate slides under a continental plate.

weathering

The breaking down of rocks through chemical or physical processes.

erosion

Processes by which rock, sand, and soil are broken down and carried away.

deposition

Process in which sediment is laid down in new locations.

geologic record

A standard time scale dividing Earth's history into time periods.

relative age

The age of a rock compared to the ages of other surrounding rock layers.

superposition

In any undisturbed sequence of rocks, the youngest layer is on top and the oldest is on bottom.

faults

Breaks in Earth's crust where rocks have slipped past each other.

intrusion

An igneous rock layer formed when magma breaks through rock layers, then cools and hardens.

absolute age

The specific, numeric age of a rock (determined by radiometric dating).

radiometric dating

The process of measuring the absolute age of rock using concentrations of radioactive isotopes and their decay index.

fossil

A remnant or impression of an organism that lived in the past.

ice core

A drill core of ice that can help tell about the climates of the past.

genotype

An organism's genetic makeup, or allele combination.

heterozygous

Genotype with two different alleles.

homozygous

Genotype with two of the same alleles.

species

A group of similar organisms that can breed and produce fertile offspring.

fossil record

Chronological collection of life's remains in sedimentary rock layers.

reproduction

Transfer of genetic information from one generation to the next.

sexual reproduction

Process by which cells from two different parents unite to produce the first cell of a new organism.

asexual reproduction

Process of reproduction involving a single parent that results in offspring that are genetically identical to the parent.

genes

DNA segments that serve as the key functional units in hereditary transmission; determine the traits.

meiosis

Cell division that results in four daughter cells each with half the number of chromosomes of the parent cell.

mitosis

Cell division that results in two daughter cells containing the same number of chromosomes as the parent cell.

egg

Female sex cell.

sperm

Male sex cell.

fertilized cell

Zygote; sperm reproductive material introduced to egg reproductive material.

trait

A characteristic that an organism can pass on to its offspring through its genes.

DNA

(Deoxyribonucleic acid) carrier of genetic information present in living organisms.

alleles

Different versions of a gene.

dominant

Trait that covers over, or dominates, another form of that trait.

recessive

Trait of an organism that can be masked by the dominant form of a trait.

codominant

Two genetic traits are fully expressed and neither dominates in the heterozygote.

incomplete dominance

Both traits blend to create a new phenotype for the heterozygote.

phenotype

An organism's physical appearance, or visible traits.