H_Phy

Week #10 --

Quiz on 04-09-10

Week #10 -- Due on 04-09-10

accuracy

the extent to which a measurement is in proximity to the standard or expected value

acid

a substance that increases the H⁺concentration when added to a water solution

activation energy

the least amount of energy required to start a particular chemical reaction

adaptation

a particular development, behavior, or physiological change in a population of organisms, in response to changes in the populations

amino acids

an organic molecule containing an amino (-NH₂) and a carboxyl (-COOH) group from which proteins are synthesized

aqueous

a solution containing water

astronomical unit

the average distance from Earth to the Sun, approximately 150 million kilometers

atomic number

the number of protons in an atom’s nucleus; the atomic number determines an element’s placement on the periodic table

base

a substance that increases the OH^–concentration of a solution; a proton acceptor

biome

a complex biotic community characterized by the interaction of living organisms and climatic factors

Week #11 --

Quiz on 04-16-10

Week #11 -- Due on 04-16-10

*catalyst*	a substance that speeds up or slows down the rate of a reaction without being consumed or altered
*centrifugal*	the motion away from center or axis
*centripetal force*	the force on an object required to keep this object on a circular path, pulling toward the center of the circle
*compound*	a substance made up of at least two different elements held together by chemical bonds that can only be broken down into elements by chemical processes
*concentration*	the relative amount of a particular substance, a solute, or mixture

*conservation of mass*	the principle that mass cannot be created or destroyed; also conservation of matter
*convergent boundary*	area where two tectonic plates collide
*covalent bond*	a chemical bond between two atoms of the same or different elements in which each atom shares an electron
*diffraction*	the bending of a wave around an obstruction
*DNA*	a nucleic acid that carries genetic material; present in all cellular organisms

Week #12 --

Quiz on 04-23-10

Week #12 -- Due on 04-23-10

*electromagnet*	a magnet consisting of a coil of wire wrapped around a core that becomes strongly magnetized when current flows through the coil producing a magnetic field
*electromagnetic waves*	waves generated by the oscillation of a charged particle and characterized by periodic variations of electric and magnetic fields
*fault*	a rock fracture along which movement or displacement of Earth’s crust has taken place
*first law of thermodynamics*	a law that states the internal energy in a system remains constant and the change in thermal energy of a system is equal to the work done on the system
*genotype*	the sum total of the genetic information contained in an organism
*half-life*	the amount of time required for half of an original sample of radioactive material to decay or undergo radioactive transformation
*heat of fusion*	the amount of heat energy required to convert a unit mass of substance from a solid to a liquid through melting at a constant temperature and pressure
*heat of vaporization*	the amount of heat energy needed to change a unit mass of substance from a liquid to a gas at its boiling point
*indicator*	a chemical compound that changes color depending on the pH of the solution or other chemical change

Week #13 --

Quiz on 04-30-10

Week #13 -- Due on 04-30-10

Kelvin

fundamental SI unit of temperature where zero degrees Kelvin is equal to absolute zero (One degree Kelvin equals one degree Celsius.)

mass number

the total number of protons and neutrons in a nucleus

membrane

a thin layer of tissue that surrounds or lines a cell, a group of cells, or a cavity; any barrier separating two fluids

mid-ocean ridge

a continuous, seismic mountain range extending across the floor of the world’s major oceans; area where two oceanic plates are moving away from each other; area where new crustal material may be released

molecule

the smallest unit of matter of a substance that retains all the physical and chemical properties of that substance; consists of a single atom or a group of atoms bonded together

momentum

a vector quantity that is the product of an object’s mass and velocity; the general effect of ongoing motion

mutation

the process by which a gene undergoes a change in DNA sequence or a structural change

natural selection

the theory stating every organism displays slight variations from other organisms of its kind, and the struggle for limited natural resources results in individuals with certain natural variations adapted to their specific environments

niche

the unique position occupied by a particular species in terms of the area it inhabits and the function it performs within the community

nuclear fission

the process by which an atomic nucleus splits into two or more large fragments of comparable mass, simultaneously producing additional neutrons and vast amounts of energy

Week #14 --

Quiz on 05-07-10

Week #14 -- Due on 05-07-10

nuclear fusion

the process by which two lighter atomic nuclei combine at extremely high temperatures to form a heavier nucleus and release vast amounts of energy

*permeability*	the capability of a porous substance or membrane to allow a fluid or gas to enter it; the measure or degree to which a substance can be penetrated by a liquid or gas
pH	a symbol for the measure of the acidity or alkalinity of a solution
*phenotype*	the appearance or other observable characteristic of an organism resulting from the interaction of its genetic makeup and its environment
*precision*	the degree of accuracy or exactness of a measurement or tool
*product*	a substance or compound resulting from a chemical reaction
*protein*	a biological macromolecule composed of one or more chains of amino acids
*rate of reaction*	the speed at which reactants are consumed and products are produced in a given reaction
*reactant*	any substance or molecule that participates in a chemical reaction
*rift valley*	a long, narrow valley in Earth’s crust where two continental plates are separating or between two faults

Week #15 --

Quiz on 05-14-10

Week #15-- Due on 05-14-10

*RNA*	a single-stranded nucleic acid consisting of a phosphate group and one of four nitrogenous bases that encodes information needed to synthesize proteins
*second law of thermodynamics*	a law that states all natural processes proceed in a preferred direction (e.g., heat flows from high temperature regions to low temperature regions)
*solar mass*	the quantity equal to the mass of the Sun
*solubility*	the ability or tendency of one substance to dissolve in another at a given temperature and pressure
*species*	a group of organisms of common ancestry able to reproduce only among themselves and usually geographically distinct

stimulus	a condition that produces a response
succession	the progressive replacement, on a single site, of one type of community by another
vector	a physical quantity with both a magnitude and direction
velocity	the time rate at which a body changes its position vector; quantity whose magnitude is expressed in units of distance over time

Week #16 --

Quiz on 05-21-10

Week #16 -- Due on 05-21-10

abiotic

an environmental factor not associated with the activities of living organisms

acceleration

rate of change in velocity, usually expressed in meters per second; involves an increase or decrease in speed and/or a change in direction

air resistance

force of air on moving objects

allele

any of two or more alternate forms of a gene that an organism may have for a particular trait

amplitude

in any periodic function (e.g., a wave) the maximum absolute variation of the function

asexual reproduction

a form of reproduction in which new individuals are formed without the involvement of gametes

biodiversity

the existence of a wide range of different species in a given area or specific period of time

biotic

factors in an environment relating to, caused by, or produced by living organisms

calorie

unit of energy; the amount of heat needed to raise one gram of water one degree Celsius at standard atmospheric pressure

chemical weathering

the breakdown and alteration of rocks at or near Earth’s surface as a result of chemical processes

circuit

an interconnection of electrical elements forming a complete path for the flow of current

Week #17 --

Quiz on 05-28-10

Week #17 -- Due on 05-28-10

conduction

the transmission of heat through a medium and without the motion of the medium

conservation of energy

a fundamental principle stating energy cannot be created nor destroyed but only changed from one form to another

convection

heat transfer in a gas or liquid by the circulation of currents from one region to another

crest

the peak or highest point on a wave

crust

outermost layer of Earth covering the mantle

dependent variable

factor being measured or observed in an experiment

deposition

the process by which sediment is carried by forces (e.g., wind, rain, or water currents) and left in a certain area

diffraction

the change in direction of a wave caused by passing by an obstacle or traveling through an opening

dominance

tendency of certain (dominant) alleles to mask the expression of their corresponding (recessive) alleles

ecosystem

an ecological community, together with its environment, functioning as a unit

efficiency

the relative effectiveness of a system or device determined by comparing input and output

Week #18 --

Quiz on 06-02-10