sciencesemest
Terms
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- a system of knowledge and the methods you use to find that knowledge
- science
- the use of knowledge to solve practical problems
- technology
- the study of composition, structure, properties, and reactions of matter
- chemistry
- the study of matter and energy and the interactions between the two through forces and motion
- physics
- a wel tested explanation for a set of observatios or experimental rules
- theory
- proposed answer to a question
- hypothesis
- An organized plan for gathering, organizing, and communicating information
- scientific method
- The variable that causes a change in the other
- manipulated variable
- the variable that changes in response to the manipulated variable
- responding variable
- an experiment in which the manipulated variable is deliberately changed at a time.
- controlled experiment
- a statement that summarizes a pattern found in nature
- scientific law
- a representation of an object or an event
- model
- a way of expressing a value as a product of a number between 1 and 10 and a power of 10.
- scientific notation
- the straight line distance between two points (m)
- length
- the quantity of matter in an object or sample (kg)
- mass
- the amt. of space taken up by an object
- volume
- the ratio of an object's mass to is volume (Mass over Volume)
- density
- a revised version of the metric system
- SI
- all the digits that are known in a measurement plus the last digit that is estimated
- significant figures
- a ratio of equivalent measurements that is used to convert a quantity expressed in one unit to another unit
- conversion factor
- the closeness of a measurement to the actual value of what is being measured
- accuracy
- an instrument that measures temperature, or how hot an object is
- thermometer
- steepness of a line - ratio of a vertical change to the corresp. horizontal change (Rise over run)
- slope
- a relationship in which the ratio of two variables is constant.
- direct proportion
- branches of science
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three general: Physical, earth and space, and life.
chemistry physics = physical science & chemistry
geology & astronomy = earth & space sciences
biology = life science - the smallest particle of an element
- atom
- a substance that cannot be broken down into simpler substances
- element
- a substance made from two or more simpler substances and can be broken down into those simpler substances
- compound
- matter that always has exactly the same composition
- pure substance
- substances are so evenly distributed that it is difficult to distinguish one substance in the mixture from another
- homogeneous mixture
- the parts of the mixture are noticeably different from one another
- heterogeneous mixture
- property can vary because the composition is not fixed
- mixture
- when substances dissolve and form a homogeneous mixture
- solution
- a heterogeneous mixture that seperates into layers over time
- suspension
- contains some particles that are intermediate in size & do not seperate into layers.
- colloid
- any characteristic of a material that can be observed or measured without changing the composition of the substances in the material.
- physical property
- the tendency of a liquid to keep from flowing
- viscosity
- A materials ability to allow heat to flow
- conductivity
- the ability of a solid to be hammered without shattering
- malleability
- to be drawn into thin wires
- ductile
- the temp. at which a substance changes from a solid to a liquid
- melting point
- the temperature at which a substance boils
- boiling point
- process that seperates materials based on the size of their particles
- filtration
- process that seperates the substances in a solution based on their boiling points
- distillation
- occurs when some of the properties of a material change
- physical change
- any ability to produce change in the composition of matter
- chemical property
- a material's ability to burn in the prescence of oxygen.
- flammability
- how readily a substance combines chemically with another
- reactivity
- occurs when a substance reacts and forms one or two more substances
- chemical change
- any solid that forms and seperates from a liquid mixture
- precipitate
- that which has mass and occupies space
- matter
- state of matter in which materials have a definite shape and a definite volume
- solid
- state of matter in whic a material has a definite olume but not a definite shape
- liquid
- state of matter in which a material has neither a definite shape nor a definite volume
- gas
- the energy an object has due to its motion
- kinetic energy
- the result of a force distributed over an area
- pressure
- a temperature of 0 K
- absolute zero
- state of matter in which atoms have been stripped of their electrons
- plasma
- the volume of a gas is directly porportional to its temperature in kelvins if the pressure and number of particles of gas are constant
- Charles' law
- the volume of a gas is inversely porportional to its pressure if they temperature and the number of particles are constant
- Boyle's law
- reversible physical change that occurs when a substance changes from one state of matter to another
- phase change
- absorbs energy from its surroundings
- endothermic
- realeases energy to its surroundings
- exothermic
- amount of energy it takes for something to melt (Joules)
- heat of fusion
- the phase change in which a substance changes from a liquid into a gas
- vaporization
- the processt that changes a substance from a liquid to a gas at temperatures below the substance's boiling point.
- evaporation
- pressure caused by collisions and walls
- vapor pressure
- phase change in which a substance changes from a gas or vapor to a liquid.
- condensation
- phase change in which a substance changes from a solid to a gas or vapor without changing to a liquid first.
- sublimation
- when a gas or vapor changes directly into a solid without first changing to a liquid
- deposition
- a row in a periodic table of elements
- period
- a positively charged subatomic particle that is found in the nucleus of an atom
- proton
- negatively charged subatomic particle that is found in the space outside the nucleus of an atom
- electron
- a neutral subatomic particle that is found in the nucleus of an atom
- neutron
- a unique number for each element that equals the number of protons in an atom of that element
- atomic number
- the sum of the number of protons and neutrons in the nucleus of an atom
- mass number
- atoms of a given element that have different numbers of neutrons and different mass numbers
- isotopes
- the possible energies that electrons in an atom can have
- energy levels