Science Midterm Review
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118 terms
Terms | Definitions |
|---|---|
 theory | explanation of things or events that is based on knowledge gained from many observations and experiments |
| science | systematic way of learning more about the natural world that provides possible explanations to questions and involves using a collection of skills |
| scientific theory | a possible explanation for repeatedly observed patterns in nature supported by observations and results from many investigations |
| scientific law | a rule that describes a pattern in nature but does not try to explain why something happens |
| system | a set of objects or parts that form a whole |
| life science | study of living systems and how they interact |
| Earth science | study of Earth systems and systems in space, including weather and climate systems, and the study of nonliving things such as rocks, oceans, and planets |
| physical science | study of matter, which is anything that takes up space and has mass, and the study of energy, which is the ability to cause changes |
| technology | use of science to help people in some way |
| observation | a record of description of an occurrence or pattern in nature |
| hypothesis | reasonable guess that can be tested and is based on what is known and what is observed |
| infer | to draw a conclusion based on observation |
| controlled experiment | involves changing one factor and observing its effect on one thing while keeping all other things constant |
| variable | factor that can be changed in an experiment |
| independent variable | factor that is intentionally varied by the experimenter |
| dependent variable | factor that may change as a result of changes purposefully made to the independent variable |
| constant | variable that is not changed in an experiment |
| scientific method | processes scientists use to collect information and answer questions |
| model | any representation of an object or an event that is used as a tool for understanding the natural world; can communicate observations and ideas, test predictions, and save time, money, and lives |
| theories/laws | theories: explain how nature works laws: describes what nature does under certain conditions both: based on tested hypothesis, supported by data, and help unify a particular field |
| observation/inference | observation: a recored or description of an occurrence or pattern in nature inference: a drawn conclusion based on observations |
| density | mass of an object divided by its volume D = M/V |
| earthquake | sudden release of energy within Earth's crust that causes wave movement in the rock layers of the crust |
| lithosphere | rigid layer of Earth about 100km thick, made of the crust and a part of the upper mantle |
| inner core | solid, innermost layer of Earth's interior that is the hottest part of Earth and experiences the greatest amount of pressure |
| outer core | layer of Earth that lies above the inner core and is thought to be composed mostly of molten metal |
| plate | section of Earth's crust and rigid, upper mantle that moves slowly around the asthenosphere |
| mantle | largest layer of Earth's interior that lies above the outer core and is solid, yet flows slowly |
| crust | Earth's outermost layer that is the thinnest under the oceans and thickest through the mountains and contains all features of Earth's surface |
| subduction | a type of plate movement that occurs when one plate sinks beneath another plate |
| fault | large fracture in rock along which movement occurs |
| erosion | removal process by which products of weathering are moved to other locations |
| fault-block mountain | sharp, jagged mountains made of huge, tilted blocks of rock that are separated from surrounding rock by faults and form because of pulling forces |
| folded mountain | mountain that forms by the folding of rock layers caused by compressive forces |
| unwarped mountain | mountain that forms when forces inside Earth push up on the crust |
| volcano | an opening in Earth's surface that erupts sulfurous gases, ash, and lava; generally a mountain-like structure |
| isostasy | principle stating that Earth's lithosphere floats on a plastic-like upper part of the mantle called the asthenosphere |
| Earth's interior | four specific layers: inner core: innermost layer, made of solid iron, pressured, hottest part of Earth outer core: lies above inner core, made of molten metal, slows down seismic waves, liquid iron mantle: largest layer, thickest layer, solid, but flows crust: outermost layer, thinnest, contains Earth's features |
| plate movement | all are theories; convection, density differences (uneven heating), ridge push (causes ocean plates to slide), slab pull (plates sink when colliding) plates are convergent (move together), divergent (move apart), and slide past each other |
| mountains and shaping forces | fault block: made of huge, tilted blocks of rock that are separated from surrounding rock by faults; tension forces (pull) folded: formed by the folding of rock layers; compression forces (push) unwarped: formed when forces inside Earth push up on the crust; compression forces (push) volcanic: form when lama and ash build up in one area over time; tension forces (pull..?) |
| acid rain | acidic moisture, with a pH below 5.6 |
| weathering | natural mechanical or chemical process that causes rock to change by breaking them down and causing them to crumble |
| mechanical weathering | process that breaks rocks down into smaller pieces without changing them chemically |
| soil | mixture of weathered rock, organic matter, water, and air that evolves over time and supports the growth of plant life |
| topography | configuration of surface features, including shape, position, and slope; also influences the type and composition of soils that develop |
| chemical weathering | process in which the chemical composition of rocks is changed by agents such as natural acids and oxygen |
| mass movement | occurs when gravity alone causes rock or sediment to move down a slope |
| cirque | a large bowl formed by valley glaciers by removing rock from mountaintops |
| glacier | formed in cold regions; two types: continental and valley |
| loess | accumulation of silt when it is deposited |
| runoff | water that flows over Earth's surface |
| sheet flow | water flowing downhill as a thin sheet |
| mechanical and chemical processes | mechanical--ice wedging: frozen water in cracks expands, temperature rises, and causes ice to thaw (cycle that breaks up rocks) gravity: pulls large rocks down to break plants and animals: plants grow in cracks where water collects and roots expand, animals burrow through rock, loosen soil, and break rock apart wind: takes sediments away, breaking them down chemical--natural acids: "everyday" elements combine to form acids, cause reactions or formations, and thus change chemical composition plant acids: tannin/produced by plants, dissolve rock minerals, weaken rock sulfuric acid: mixes with water to form acids water: mixes with elements to form acids oxygen: oxidation causes minerals containing iron to weather due to oxygen and weakens rock |
| factors of soil formation | parent rock: breaks down and forms smaller rocks after weathering slope of land: with topography, influences soil development climate: affects amount of organic material in soil time: needed for rocks to weather and soil to form organisms: lichens take nutrients starting to break down, roots break down parent rock |
| agents of erosion | gravity: force that pulls every object toward every other object ice: causes glaciers, buries mountain ranges wind: lifts and carries sediments water: runoff, faster means more material |
| element | a substance that cannot be broken down into simpler substances |
| period | horizontal row of elements in the periodic table whose properties change gradually and predictably |
| group | family of elements in the periodic table that have similar physical or chemical properties |
| metal | element that has luster, is malleable, ductile, and a good conductor of hear and electricity |
| nonmetal | element that is usually a gas or brittle solid at room temperature and is a poor conductor of heat and electricity |
| metalloid | element that shares some properties with both metals and nonmetals |
| transition elements | elements in group 3-12 in the periodic table, all of which are metals |
| representative elements | elements in groups 1 and 2 and 13-18 in the periodic table table that include metals, nonmetals, and metalloids |
| atomic number | the number of protons in the nucleus of a given element |
| alkali metals | elements in group 1 of the periodic table; likes to combine with the halogens |
| halogens | elements in group 17 of the periodic table; likes to combine with the alkali metals |
| alkaline earth metals | elements in group 2 of the periodic table |
| noble gases | elements in group 18 of the periodic table |
| semiconductor | element that does not conduct electricity as well as a metal but conducts it better than a nonmetal |
| mass number | the sum of neutrons and protons in the nucleus of an atom |
| catalyst | substance that can make something happen faster but not change itself |
| lanthanides | the first series of inner transition elements which goes from cerium to lutetium |
| actinides | the second series of inner transition elements which goes from thorium to lawrencium |
| element key | has element, the atomic number, the symbol, the atomic mass, and the state of matter the atomic number is the number of protons in the element the symbol is (usually) a short abbreviation of the element, one to two letters the atomic mass is the sum of neutrons and protons in the nucleus of an atom the logo for the state of matter shows if the element is a solid, liquid, or gas at room temperature gases are marked with a balloon whereas solids are marked with a cube liquids are marked with a water droplet unnatural elements are marked with a bulls-eye |
| organization of periodic table | divided into groups and periods groups: contain elements that have similar physical or chemical properties periods: rows of elements in the periodic table whose chemical and physical properties change gradually and predictably the representative elements are groups 1-2 and 13-18; they include metals, metalloids, and nonmetals groups 3-12 are transition elements; all are metals the inner transition elements are placed below the main table and are called the lanthanide and actinide series |
| properties of representative elements | check out "chart template 4.2".. I can't copy and paste the chart |
| chemical change | change in which the identity of a substance changes and forms a new substance or substances |
| electron cloud | area where negatively charged electrons, arranged in energy levels, travel around an atom's nucleus |
| energy level | the different areas for an electron in an atom |
| electron dot diagram | chemical symbol for an element, surrounded by as many dots as there are electrons in its outer energy level |
| chemical bond | force that holds two atoms together |
| compound | pure substance that contains two or more elements |
| ion | atom that is no longer neutral because it has gained or lost an electron |
| ionic bond | attraction that holds oppositely charged ions close together |
| metallic bond | bond formed when metal atoms share their pooled electrons |
| covalent bond | chemical bond formed when atoms share electrons |
| molecule | neutral particle formed when atoms share electrons |
| polar bond | bond resulting from the unequal sharing of electrons |
| chemical formula | combination of symbols and numbers that indicates which elements and how mant atoms of each element are present in a molecule |
| electron arrangement in an atom | are present in energy levels around the nucleus |
| electron arrangement's effect on atom placement | arrangement of electrons is pretty much responsible for many physical and chemical properties of the element |
| ionic/covalent compounds | ionic compounds: takes oppositely charged bonds close together; either gains or loses an electron covalent compounds: bond that forms between nonmetal atoms when they share electrons both: form compounds after bonding |
| compounds/molecules | compounds: pure substances that contain two or more elements molecules: neutral particles formed when atoms share electrons |
| atom | a small particle that makes up most types of matter |
| matter | anything that takes up space and has mass |
| solid | matter with definite shape and volume; has tightly packed particles that move mainly by vibrating |
| liquid | matter with a definite volume but no definite shape that can flow from one place to another |
| viscosity | a liquid's resistance to flow |
| gas | matter that does not have a definite shape or volume; has particles that move at high speeds in all directions |
| surface tension | the uneven forces acting on the particles on the surface of a liquid |
| energy | the ability to do work or cause change |
| thermal energy | the sum of the kinetic and potential energy of the particles in a material |
| temperature | a measure of the average value of the kinetic energy of the particles in a material |
| heat | movement of thermal energy from a substance at a higher temperature to a substance at lower temperature |
| melting | change of matter from a solid state to a liquid state |
| freezing | change of matter from a liquid state to a solid state |
| vaporization | change of matter from a liquid state to a gas |
| condensation | change of matter from a gas to a liquid state |
| force | a push or pull |
| pressure | force exerted on a surface divided by the total area over which the force is exerted P = F/A |
| buoyant force | upward force exerted on an object immersed in a fluid |
| Pascal's principle | states that when a force is applied to a confined fluid, an increase in pressure is transmitted equally to all parts of the fluid |
| Archimedes' principle | states that the buoyant force on an object is equal to the weight of the fluid displaced by the object |
| states of matter and arrangement of particles | solid: matter with definite shape and volume; their particles vibrate in place and keep their shape and volume maintained.. because a solid has a specific shape, the particles make sure that that the shape and volume is the same liquid: matter that has a definite volume but no definite shape; the particles stay close together, but are free to move past one another... because a liquid has a definite volume, it must have the same weight; whereas because it has no specific shape, the particles can move around a little bit gas: matter that doesn't have a definite shape or volume; the particles in a gas move at high speeds in all directions... because a gas has no definite volume or shape, the particles are free to do pretty much whatever they want |
| thermal energy/temperature | thermal energy: the sum of the kinetic and potential energy of the particles in a material temperature: a measure of the average value of the kinetic energy of the particles in a material comparison: both use kinetic energy |
| changes of thermal energy/changes of state | thermal energy: depends on the amount of the substance and the kinetic energy of particles in the substance; during changes of state, the temperature of the substance stays the same changes of state: vaporization is change from the liquid to gaseous state; condensation is the change from gaseous state to the liquid state; sublimation is the process of a substance going from the solid to gas state without ever being in the liquid state both: depend on the amount of the substance |
| floating/sinking | water pressure increases with depth; the pressure pushing up on the bottom of the object is greater than the pressure pushing down on it because the bottom of the object is greater than on the top; if the buoyant force is equal to the weight of an object, the object will float; if the buoyant force is less than the weight of an object, the object will sink |
| pressure transmission through fluids | when a force is applied to a confined fluid, an increase in pressure is transmitted equally to all parts of the fluid a good example of Pascal's principle is hydraulic systems using this principle to increase force; the force applied to the piston (left) increases the pressure within the fluid; that increase in pressure is transmitted to the piston (right); if both pistons have the same area, the force on one piston will be equal to the other; but, if the one on the right has a greater surface area, the resulting force will be greater. The same pressure multiplied by a larger area equals greater force the formula for pressure is: pressure = force/area (P = F/A) the formula for force is: force = pressure x area (F = P x A) |
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