physical science Qt 1

Science

a system of knowledge about the natural world and the methods used to find that knowledge

Technology

the use of scientific knowledge to solve problems

Geology

the study of the origin, history and structure of Earth

Astronomy

the study of the universe beyond Earth

Scientific Method

an organized plan used for gathering, organizing and communicating information

Observation

information obtained through your senses

Hypothesis

a proposed answer to a question

Controlled Experiment

an experiment in which only one variable (independent) is deliberately changed at a time

Independent Variable

the variable that causes a change in another

Dependent Variable

the variable that changes in response to the independent variable

Controlled Variable

all other variables in an experiment (kept constant)

Scientific Theory

a well-tested explanation for a set of observations or experimental results

Scientific Law

a statement that summarizes a pattern found in nature

Length

the straight-line distance between two points

Mass

the amount of matter in an object

Volume

the amount of space taken up by an object

Density

the ratio of a materials mass to its volume

Conversion Factor

a ratio of equivalent measurements that is used to convert a quantity from one unit to another

Precision

a gauge of how exact a measurement is

Accuracy

the closeness of a measurement to the true value of what is being measures

Significant Figures (sig figs)

all of the digits in a number that are directly measured, plus the last digit (which is estimated)

Metric System (SI System)

a set of measuring units used by scientists

Direct Proportion

the relationship between two variables in which their ratio is constant

Indirect (inverse) Proportion

a relationship in which the product of two variables is a constant when all other variables are held constant

Scientific Notation

a way of expressing a value as the product of a number between 1-10 and a power of 10

Scientific Model

a visual representation that makes it easier to understand things that might be too difficult to observe

Convection

the transfer of thermal energy when particles of a fluid move from one place to another

Law of Uniformitarianism

the idea that the geologic processes that operate today also operated in the past

Geosphere

any of the almost spherical concentric matter that make up Earth and its atmosphere

Geologist

scientists who study Earth and the processes that have shaped it over time

Silicates

a rock made of compounds of silicon and oxygen, generally containing metals such as aluminum, iron or calcium

Crust

the rocky outer layer of Earth

Mantle

a thick layer of hot but solid rock beneath Earth's crust

Core

the dense sphere at Earth's center, made mostly of iron and nickel

Lithosphere

a layer of relatively cool, rigid rock that includes the uppermost part of the mantle as well as the crust

Asthenosphere

a layer of softer, weaker rock beneath Earth's lithosphere which can flow softly

Mesosphere

the lower portion of Earth's mantle

Outer Core

the outer portion of Earth's core that has liquid iron and nickel that causes the magnetic field

Inner Core

the inner sphere of the core completely solid iron and nickel with incredible pressure

Plate Tectonics

the theory that pieces of Earth's lithosphere, called plates, move about slowly on top of the asthenosphere

Plate Boundaries

the edges of tectonic plates, where they meet other plates

Continental Drift

the process in which the continents move slowly across Earth's surface

Sea-Floor Spreading

the process by which new oceanic crust is created at mid-oceans ridges, as older crust moves away

Mid-Ocean Ridge

a chain of underwater mountains

Subduction

the process by which oceanic crust sinks into the mantle through a trench

Converging

a boundary at which tectonic plates collide

Diverging

a boundary at which tectonic plates move away from eachother

Trench

a long, deep depression in the ocean floor where old oceanic crust sinks into the mantle

Seismic Waves

vibrations that carry the energy released during an earthquake

P Waves

primary waves; longitudinal waves caused by earthquakes

S Waves

secondary waves; transverse waves caused by earthquakes

Fault

a break in Earth's crust along which movement occurs

Fold

a bend in layers of rock

Epicenter

the point on Earth's surface directly above the focus of an earthquake

Focus

the location beneath Earth's surface where an earthquake begins

Stress

the forces of deformation acting on the rocks of Earths crust

Seismographs

a device that can detect and record seismic waves

Richter Scale

the most well-known scale to use for earthquakes

Volcano

a mountain that forms when magma reaches the surface

Magma

a mixture of molten rock and gases, including water vapor, which forms underground

Lava

magma that flows over Earths surface

Caldera

huge depression at the top of a volcano created when the vent or magma chamber collapse after eruption

Composite Volcano

a volcano that forms from a combination of lava and ash

Shield Volcano

a wide, relatively flat volcano that results from quiet eruptions of low viscosity lava

Viscosity

the tendency of a liquid to keep from flowing; resistance to flow

Magma Viscosity

magma's viscosity to flow; determined by temperature, water content and silica content

Hot Spot

a region where a rising column of magma extends from beneath the lithosphere to reach Earths surface

Cinder Volcano

a small steep-sided volcano formed from a combo of ash and cinder

Volcanic Rocks

then lava cools and depending on the viscosity, different rocks form

Batholith

the largest type of intrusive igneous rock mass; makes up mountains

Sill

a structure formed when magma hardens in a crack parallel to existing rock layers

Dike

a structure formed when magma hardens in a crack cutting across rock layers

Volcanic Necks

a structure formed when magma hardens in a volcanic pipe

Sedimentary Rock

rock that forms over time as sediment is squeezed and cemented together

Igneous Rock

rock that forms from magma or lava

Metamorphic Rock

rock that has been changed by temperature, pressure or reactions with hot water

Rock

a solid combination of minerals or other materials

Mineral

a naturally occurring, inorganic solid with a crystal structure and a definite chemical composition

Properties of Minerals

The properties with which minerals can be identified by; crystal structure, color, luster, streak, density, hardness, fracture, cleavage and shape.

Rock Cycle

a series of processes in which rocks continuously change from one type to another

Quiet Eruptions

volcanic eruptions that erupt quietly, lava flows that travel great distances, very hot, low silica magma

Explosive Eruptions

volcanic eruptions that are explosive, lava is hurled like projectiles, with thick, high-silica magma

Fossils

The preserved remains or traces of a living organism

Index Fossils

a fossil of a species that is easily identified, occurred over a large area, and lives for a well-defined period of time

Relative Age

the age of a rock compared to the ages of other rocks above or below it in a sequence of rock layers

Law of Superposition

law stating that in rock layers that are undisturbed, younger rocks lie above older rocks and the older rocks are at the bottom

Absolute Age

the time that passed since a rock formed

Era

a major stage in Earth's geologic history

Periods

a unit of geologic time that makes up eras

Mass Extinction

a boundary between geologic eras when many different kinds of organisms became extinct within a relatively short time

Radioactive Decay

the process in which radioisotopes decay during half-lifes

Half Life

the time required for half of a sample of a radioactive isotope to decay

Nebular Theory

states that the solar system formed from a rotating cloud of dust and gas

Solar Nebula

a large, thin cloud of dust and gas, like the one that formed our solar system

Protoplanetary Disk

a large disk shaped cloud of dust and gas, formed as the solar nebula rotated faster and flattened out

Planetesimals

asteroid-sized bodies in the protoplantetary from which the planets formed by accretion

Accretion

the process of adding mass in the formation of the planets by collisions between planetesimals

Geocentric

a description of a model of the solar system in which all of the planets revolve around Earth

Heliocentric

a description of a model of the solar system in which Earth and other planets revolve around the sun

Moon

a relatively small natural body in space that revolves around a planet