A

abiotic

non-living components (sunlight, temperature, wind, water, and rock) of an ecosystem

absolute humidity

the actual quantity of water vapour in the air, in grams of water per kilogram of air

absorb

soak up, to take up or receive by chemical or molecular reaction

absorption

a taking in or reception by molecular or chemical action, as of gases or liquids

accelerate

changing to a quicker speed, or positive increasing direction or both; a change in velocity

accelerated motion

motion with changing speed, or direction, or both; motion in which the velocity is changing

acceleration

is the rate of change of an object's speed, which may be a change in magnitude of the speed or a change of direction of the speed. (The former is a topic of study in this unit; the latter is not.)

accelerometer

a device that measures acceleration, the rate of change of an object's speed

acids

are substances that produce hydrogen ions ( H+ ) when dissolved in water. Acids are sour-tasting, good conductors of electricity, turn blue litmus paper red, and react with bases to form salts and water

adaptation

any alteration in the structure or function of an organism or any of itsparts that results from natural selection and by which the organism becomes better fitted to survive and multiply in its environment; the ability of a species to survive in a particular ecological niche because of alterations of form or behavior brought about through natural selection

aerosol

a suspension of small particles in a gas. The particles may be solid or liquid or a mixture of both

air mass

a large portion of air that is nearly uniform in temperature and humidity

albedo

is a measure of a surface's ability to reflect light

aldehyde

alkaline

a substance that may also be described as a base

altostratus

a cloud characterized by a generally uniform grey sheet or layer caused by a large air mass that is lifted then condensed usually by an incoming frontal system

ammonification

bacteria decomposers breaking down amino acids from dead animals and animal wastes into ammonia (NH₄OH)

anaerobic

is a technical word which literally means without air, specifically oxygen

anemometer

is a device used to measure wind speed. Typical units are km/h or knots

aneroid barometer

an instrument that measures atmospheric pressure based on volume changes of a sealed, partly evacuated cell

anion

is a negatively charged ion, the result of gaining one or more electrons

aqueous

containing, dissolved in, or consisting mostly of water

anticyclone

a clockwise rotation of air

atmosphere

is the gaseous envelope that surrounds the Earth-- consists of multiple layers: troposphere, tropopause, stratosphere, mesosphere, thermosphere, and exosphere

atmospheric pressure

also air or barometric pressure; the pressure exerted by air on its surroundings due to the weight of the air

atom

a unit of matter, the smallest unit of an element, having all the characteristics of that element and consisting of a dense, central, positively charged nucleus surrounded by a system of electrons

atomic mass

is the combined weight of the protons and neutrons in the atom (atomic mass = number of protons + number of neutrons)

atomic number

is the number of protons in the atom (atomic number = number of protons = number of electrons)

ATP

a chemical compound, adenosine triphosphate, that is a storage molecule for energy

autotrophic

any organism capable of self-nourishment by using inorganic materials as a source of nutrients and using photosynthesis or chemosynthesis as a source of energy, as most plants and certain bacteria and protists

avalanche

is a high-velocity flow of snow down a mountainside

average acceleration

the acceleration of an object measured over a fairly large time interval, the symbol is a_av

average speed

refers to a calculation of change in distance over a time interval for a moving object

average velocity

the displacement divided by the total time from start to finish, the overall rate of change of position

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balanced chemical equation

represents the identities and relative amounts of reactants and products in a chemical reaction. The total number of each type of atom remains the same.

barometer

is a device used to measure atmospheric pressure. Typical units are mb, mmHg, or kPa.

bases

are substances that produce hydroxide ions ( OH - ) when dissolved in water. Bases are bitter tasting, good conductors of electricity, feel slippery, turn red litmus paper blue and react with acids to form salts and water

Beaufort Wind Scale

originally a system that allows sailors to estimate wind speeds on a 0 - 12 scale, based on the motion of the sea and of objects on the ship; has been adapted for observations on land

binary compound

a compound composed of two different elements

bioaccumulation

(also called biological accumulation ) is the increase in concentration of a pollutant from the environment to the first organism in a food chain

bioamplification

(also called biomagnification ) is the tendency of pollutants to become concentrated in successive trophic levels

biochemicals

chemicals produced from organic sources known as biomass or any living matter that can be naturally and regularly replenished, including agricultural food and feed crop residues, aquatic plants, animal wastes and other waste materials

bioconcentration

physical property characterizing the accumulation of pollutants

biodiversity

a measure of the number and variety of species in an ecosystem

biogeochemical cycle

(or nutrient cycle) is the path of a nutrient through an ecosystem

biological accumulation

(also called bioaccumulation ) is the increase in concentration of a pollutant from the environment to the first organism in a food chain

biological magnification

(also called biomagnification or bioamplification ) is the tendency of pollutants to become concentrated in successive trophic levels

biomagnification

(also called biological magnification or bioamplification ) is the tendency of pollutants to become concentrated in successive trophic levels

biomass

is a measure of the mass of the dry matter contained in a group of living things

biome

describes areas on the earth with similar climate, plants, and animals.

biomechanics

The mechanics of a part or function of a living body, such as of the heart or of locomotion

biosphere

the life zone of Earth, including the lower part of the atmosphere, hydrosphere and upper part of Earth's crust

biotic

living components (animals and plants) of an ecosystem

biotic potential

is the maximum number of offspring that a species could produce if resources were unlimited

blizzard

is a severe storm with strong winds (greater than 40 km/h), low temperatures, and blowing snow that reduces visibility to 1 km or less and that lasts for at least three hours

booms

a floating barrier, usually a chain supported by interspersed buoyant elements, for blocking a waterway

Bunsen burner

a small laboratory burner consisting of a verticl metal tube connected to a gas source, and producing a very hot flame from a mixture of gas and air let in through a series of adjustable holes at the base

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carbon sink

a sink absorbs more carbon than it gives off

carnivore

is an animal with a diet consisting mainly of meat, whether it comes from animals living or dead (scavenging)

carrying capacity

is the maximum number of individuals of a species that an ecosystem can support

catalyst

is a substance that changes the rate of a chemical reaction but is not changed in the reaction

cation

is a positively charged ion, the result of losing one or more electrons

caustic

a substance capable of burning, corroding, dissolving, or eating away by chemical action

cellular respiration

is the process by which most living things generate useful energy by combining oxygen and sugars to produce carbon dioxide and water

centrifugal force

an outwardly directed force acting on a body rotating around a central point that is equal in magnitude but opposite in direction

change

to make a difference in the state or condition of something

characteristics

distinguishing traits

chemical change

 the alteration of a substance into one or more different substances with different properties

chemical energy

the energy held in the covalent bonds between atoms in a molecule. Every bond has a certain amount of energy

chemical equation

represents the reactants and products in a chemical reaction using their symbols or formulas

chemical reaction

is a process that involves the formation of new substances with new properties

chlorophyll

pigments that absorb light photons

chloroplast

the site of photosynthesis, an organelle that contains chlorophyll

cirrus

high-level clouds made of ice crystals, formed by deposition

classifying

is a systematic procedure developed by humans to impose order on collections of objects or events

clearcutting

is a practice in which all/most trees in an area are harvested, to facilitate the regrowth of a new stand or land development

climate

the weather conditions of a location averaged over many years

climate change

a change in the "average weather" that a given region experiences. Average weather includes all the features we associate with the weather such as temperature, wind patterns, and precipitation

climax community

a community that has reached the stable stage

closed system

one in which substances do not enter or leave

cloud

a collection of small water or ice particles occurring above the Earth's surface. Clouds are classified according to their height of occurrence and shape

coagulate

to gather together or form into a mass or group, to clump together

coalesce

or coalescence, a process in which cloud droplets collide and blend together forming raindrops

cold air mass

a large portion of cold air that is nearly uniform in temperature and humidity

cold front

the leading edge of a cold air mass

collision model

states that the number of effective collisions (above activation energy) of reactant molecules affects the rate of a chemical reaction

combustion

the reaction of a substance with oxygen to produce oxides, light and heat. Most combustion reactions involve organic compounds

community

all of the organisms in an ecosystem

competition

the struggle among organisms, both of the same and of different species, for food, space, and other vital requirements

compound

a pure substance composed of two or more elements whose composition is constant

concentration

the amount of a substance contained in a given amount of a solution or mixture; the amount of solute in a given amount of solvent

condensation

the act or process of changing a vapour or gas to a liquid or solid form

condensation nuclei

tiny particles, such as dust or salt which stimulate droplet formation

conduction

the transfer of energy through a substance by the collision of particles

conductor

a substance, body, or medium that allows heat, electricity, light, or sound to pass along it or through it

constant acceleration

a rate of change in speed or velocity that does not change during the acceleration, also called uniform acceleration

constant motion

motion where both direction and speed remain unchanged

constant speed

travelling the same distance over successive equal time intervals, uniform motion

constant velocity

motion in which both direction and speed stay the same

consumer

an organism, usually an animal, that feeds on plants or other animals

control

a part in an experiment that is not involved in the procedures affecting the rest of the experiment, thus acting as the standard against which the results are compared

convection

the transfer of energy by the movement of particles in a fluid (liquid or gas)

conventions

agreements among scientists to measure and calculate using the same units and symbols

co-ordinate graph

a grid that has data points names as Cartesian pairs, such as (4, 3)

Coriolis Effect

the apparent change in direction of a moving object in a rotating system. In weather systems, this refers to the curvature of the prevailing wind systems (westerlies and trade winds) due to the Earth's rotation

corrosion

a process by which something, especially a metal, is destroyed progressively by chemical action, as iron is when it rusts

corrosive

a substance that will corrode or eat away materials

cost-benefit analysis

a process that weighs the advantages (benefits) and disadvantages (costs) of different courses of action

covalent bond

the bond formed by two or more atoms sharing one or more pairs of electrons

critically endangered

a species that is close to extinction in all parts of Canada or in a significantly large location

cumulonimbus

rain or snow bearing cumulus clouds, also know as storm clouds

cumulus

all-level puffy clouds that often have flat bases; formed by convection currents or by the meeting of air masses

cyclone

a low pressure, air mass that is rotating inward (counter clockwise in the Northern Hemisphere, clockwise in the Southern Hemisphere)

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deceleration

changing to a slower speed, or negative decreasing direction or both; a change in velocity

decomposer

an organism that feeds on detritus (garbage), in the process releasing nutrients to the soild and water, where they can be used by other organisms

decomposition

a compound,"splits-up" into two or more compounds and/or elements. (example mercury(II) oxide will, upon heating, decompose into mercury metal and oxygen)

deforestation

The removal of forests by cutting and burning so the land can be used for agricultural, residential or industrial building sites, or by harvesting trees for building materials or fuel.

denitrification

the conversion of nitrite or nitrate to gaseous end products NO, N₂O, and N₂ by denitrifying bacteria

dense

having the component parts closely compacted or crowded together

density

a measure of the mass per unit length, area or volume of an object

density-dependent factors

factors that increase in significance as a population grows (e.g., disease due to overcrowding)

density-independent factors

factors that do not depend on the population size (e.g., fire)

dependent variable

a variable affected by another variable (independent variable) or by a certain event

deposition

a process in which water vapour changes from a gas directly to a solid

detritus

waste from plants and animals, including dead remains

detritus food chain

a food chain that involves the decomposing of waste from plants and animals, including dead remains

detritivore

any organism which obtains most of its nutrients from the detritus in an ecosystem

dew

water vapour that condenses on cool surfaces near the Earth's surface, typically in the morning

dew point

the temperature to which air would have to be cooled to reach saturation with respect to liquid water

diatomic molecule

molecules formed of exactly two atoms, of the sa me or different chemical elements

displacement

the change of position of an object, this is a vector quantity

distance

the length of path traveled between two points

distillation

is a method of separation of substances based on differences in their properties

doppler radar

a device used to determine how fast an object is moving towards or away from the radar site as well as the actual speed of the object

double covalent bond

a bond formed by the the sharing of two pairs of electrons (four electrons)

downdraft

an air movement created by the cooling effect of rain, particularly in a storm cloud

drizzle

falling water droplets that have a diameter between 40 µm and 0.5 mm

drought

a period in which the rainfall for an area is much less than average

dry bulb

an ordinary thermometer with a dry bulb, used to measure air temperature

E

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ecological footprint

a measure of an individual's or a population's impact on the environment

ecological pyramids

graphical representation of energy flow through an ecosystem

ecosystem

the living and non-living components of a biological community and their interrelationships

efficiency

a general term, to capture the amount of waste or other undesirable features

effluent

sewage or other liquid waste that is discharged into a body of water

elasticity

the property of a substance that allows it to change its length, volume or shape in response to a force acting on it and to recover its original form when the force is removed.

electromagnetic radiation

energy transmitted through space in the form of electromagnetic waves; the energy that radiates from all things in nature and from man-made electronic systems, including cosmic rays, gamma rays, x-rays, ultraviolet light, visible light, infrared light, radar, microwaves, TV, radio, cellphones and all electronic transmission systems

electron

a stable subatomic particle having a negative electric charge

electronegativity

is a measure of the ability of an atom or molecule to attract electrons in the context of a chemical bond

electron shell

a grouping of electrons surrounding the nucleus of an atom; the chemical properties of an atom are determined by the outermost electron shell

electropositivity

having a tendency to release electrons

element

any substance that cannot be broken down to any other substance by ordinary means. It is made up of one kind of atom

Elodea

American waterweed, commonly used as an aquarium plant

emigration

is the movement of members from a population

endangered

a species that is close to extinction in all parts of Canada or in a significantly large location

endemic

native to or confined to a certain region as a plant that is native to a certain limited area; "it is an endemic found only this island

endothermic

chemical reactions where energy is absorbed from the surroundings (baking a cake)

energy

the capacity to do work

entropy

is a measure of disorder of a system, eg. the higher the disorder, the higher the entropy value

environment

surroundings of an organism, including the biotic and abiotic parts

Environment Canada

federal government agency that provides detailed, up to the minute weather forecasts and also carries out research to study and improve Canada's air, land and water quality

equilibrium

the state in a reversible chemical reaction in which the reaction and its reverse reaction proceed at the same rate and balance each other so there is no further change

erosion

is displacement of solids (soil, mud and rock and other particles) by the agents of ocean currents, wind, water, or ice by downward or down-slope movement in response to gravity or by living organisms

evaporation

the process by which molecules in a liquid state (e.g. water) spontaneously becomes a gas (e.g. water vapor), without being heated to the boiling point

excrement

waste matter (as urine or sweat but especially feces) discharged from an organism

exothermic

chemical reactions where energy is released to surroundings(burning wood)

extinct

a species that is no longer found anywhere on Earth

extirpated species

no longer exists in one particular area, but still exists in other locations

extrapolation

an estimate of values outside what is shown on a graph

eye

(of a hurricane) the calm, clear central zone of a hurricane, averaging 30 km wide

eye wall

the area outside of the eye of the hurricane

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filtration

the process of passing or putting something through a filter

final velocity

is the instantaneous velocity of an object at the time it is last observed

flood

is excess water from rain, rivers, or oceans that cannot be absorbed by the surrounding land

fog

is water droplets, ice crystals, or smoke particles that collect near the Earth's surface and that reduce visibility to less than 1 km

food chain

shows the movement of energy through a system by indicating the path of food from a producer to a final consumer

food web

is a pictorial representation of the feeding relationships between organisms in an ecosystem and consists of interlocking food chains

force

an influence that changes the motion of an object

forensic science

is the application of a broad spectrum of sciences to answer questions of interest to the legal system. This may be in relation to a crime or to a civil action.

formula mass

also referred to as molecular mass -- this is the total mass of a molecule determined by adding the total atomic masses of all of the atoms in the molecule

fossil fuels

are hydrocarbons found within the top layer of the earth’s crust. Fossil fuels are non-renewable resources because they take millions of years to form and reserves are being depleted much faster than new ones are being formed

fractions

various components of crude oil

frame of reference

a framework that is used for the observation and mathematical description of physical phenomena and the formulation of physical laws, usually consisting of an observer, a coordinate system, and a clock or clocks assigning times at positions with respect to the coordinate system

free living

surviving without being attached to another organism or substrate

freezing rain

a dangerous weather condition, created when the ground temperature is below freezing, but the air is warm enough to allow rain to fall; the rain freezes instantly, creating a solid coating of ice

friction

the resistance created by rubbing two objects against each other

front

is the leading edge of an air mass

frontal low

a low pressure system created by rising warm air created by a disturbance in a stationary front

fungicide

chemical compounds used to prevent the spread of fungi in gardens and crops, which can cause serious damage resulting in loss of yield and thus profit

G

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genetic code

the formula needed to produce the several thousands of different proteins required in our bodies. It is the genetic material, the DNA, in our cells that provides the information

girth

distance around something thick and cylindrical such as a tree trunk or somebody's waist

global warming

the increase in the average Earth's temperature due to an increased concentration of greenhouse gases in the atmosphere that amplifies the Greenhouse Effect

gradient

is a description of a pattern that includes the magnitude and direction of the change

granum

stacks of thylakoids in a chloroplast

grazer food chain

a food chains that includes green plants, herbivores, and so on. where living plants are directly consumed

gravity

the force of attraction exerted by a celestial body, such as the Earth on objects at or near its surface, drawing them toward the centre of the body

greenhouse effect

a natural process by which a planet's atmosphere traps thermal energy from the Sun, causing the temperature of the atmosphere to increase

greenhouse gases

such as water vapour, carbon dioxide, methane, ozone, nitrous oxides, and chlorofluorocarbons absorb and re-emit infrared radiation in the atmosphere

group

the vertical columns of elements in the periodical table

gyres

circular ocean currents that flow clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere

H

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habitat

the natural environment of an organism; place that is natural for the life and growth of an organism

hail

is frozen water droplets that are created by cycling through highly active thunderclouds many times

heat

a form of energy associated with the motion of atoms or molecules and capable of being transmitted through solids and fluids by conduction, through fluid by convection, and through empty space by radiation

heat capacity

is a measure of how much energy is required to raise the temperature of a substance

heat of fusion

the amount of energy required to melt 1.0 g of a solid into a liquid

heat of vaporization

the amount of energy required to convert 1.0 g of a substance from a liquid stat into a gaseous state

heat wave

a period of three days or more of hot weather with temperatures over 32° C

herbicide

a chemical substance used to destroy or inhibit the growth of plants, especially weeds

herbivore

is a form of predation in which an organism known as an herbivore, consumes principally autotrophs such as plants, algae and photosynthesizing bacteria

heterotrophic

an organism that cannot synthesize its own food and is dependent on complex organic substances for nutrition

high pressure system

an area with higher atmospheric pressure relative to the surrounding areas, which causes air to sink and usually produces non-stormy weather conditions

human impact

the effect that humans have on the Earth's natural resources, both animals and inanimate, for its survival, consumption and enjoyment

humidex scale

a combination of temperature and relative humidity designed to help guide people on what to wear, how active to be outdoors and when to take extra care if health problems exist

humidity

is the amount of water vapour in a sample of air

hurricane

a vast, rotating thunder storm system up to 500 km wide, generated by deep warm water in the mid-Atlantic Tropics, wind speeds exceed 120 km/h

hydrocarbons

are organic compounds composed solely of hydrogen and carbon atoms

hydrologic cycle

(or water cycle) is a model that describes the storage and movement of water between the atmosphere, hydrosphere, and lithosphere

hydrosphere

is the waters of the Earth

hygrometer

(or psychrometer) is a device used to measure the relative humidity based on the absorption of water by certain materials

hypothesis

a testable proposal that is an explanation for an observation or question

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ice storm

is where falling rain freezes instantly when coming in contact with a surface, forming a coat of ice on the surface

immigration

the movement of members into a population

incline

lean, slope, rise, fall, angled from horizontal

incomplete combustion

occurs when there is not enough oxygen available for a combustion reaction which leads to the production of carbon monoxide instead of or in addition to carbon dioxide, when burning a hydrocarbon

independent variable

a variable whose value determines the value of other variables, a manipulated variable in an experiment that determines the change in a dependent variable.

indicators

provide evidence that a chemical reaction might have taken place such as: a colour change, an odour change, the formation of a new substance (precipitate), the emission of a gas, and the release or absorption of heat or light. Indicators are substances that change colour at specific pH levels

indigenous

having originated in and being produced, growing, living, or occurring naturally in a particular region or environment

infrared radiation

invisible radiation in the part of the electromagnetic spectrum characterized by wavelengths just longer than those of ordinary visible red light and shorter than those of microwaves or radio waves

initial motion

starting a change of position, the speed and direction upon first observation of a motion

inorganic

are considered to be compounds of mineral, not biological, origin

insecticide

a chemical substance used to kill insects

instantaneous acceleration

acceleration measured at a specific instant in time, the symbol is a_inst

instantaneous speed

refers to the actual speed of an object at a particular instant in time

instantaneous velocity

refers to the actual velocity (speed and direction) of an object at a particular instant in time

interactions

the relationships between organisms in an ecosystem such as mutualism, predation, and symbiosis

internal

situated or existing inside of something, pertaining to the insider or inner part

International System of Measurement (SI)

the international system of measurement units, including such terms as kilogram, metre and second

interpolation

to estimate a value between two known points on a graph

interpreting data

means to find patterns in data collections that can lead to generalizations about the data

interspecific competition

the struggle between individuals of different species for resources

interval

a space between two things, points, limits

intraspecific competition

the struggle between members of a population for scarce resources

introduced species

is an organism that is not native to the place or area where it is considered introduced and instead has been accidentally or deliberately transported to the new location by human activity

invasive species

means an alien species whose introduction does, or is likely to, cause economic or environmental harm or harm to human health

invertebrates

an animal that lacks a backbone or spinal column like a mollusk

ion

is an atom that has become charged by gaining [resulting in a negative ion (e.g. Cl-)] or losing one or more electrons [resulting in a positive ion (e.g. Na+)]

ionic bond

is the bond formed by the transfer of electrons from one atom (usually a metal) to another (usually a non-metal).

ionic compound

is a neutral compound that consists of positive and negative ions held together by an ionic bond

ionosphere

a layer of charged particles lying within the thermosphere and uper mesosphere; created when atoms and molecules in the atmosphere absorb high-energy ultraviolet radiation from the sun

isobars

are lines on weather maps that connect points of equal pressure

isotherms

are lines on weather maps that connect points of equal temperature

isotopes

atoms that have the same number of protons (atomic number remains the same) but a different number of neutrons

J

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

jet stream

is the name for high-speed winds in the upper troposphere

K

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

kinematics

the branch of mechanics that deals with pure motion, without reference to the masses or forces involved in it

L

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

latitude

a measure in degrees, of distance north or south of the equator

Law of Conservation of Mass

states that in a chemical reaction the total mass of reactants is equal to the total mass of the products

legumes

a plant of the pea family that has a pod or seed used as food

lichens

are symbiotic associations of a fungus with a photosynthetic partner (an algae) that can produce food for the lichen from sunlight

lightning

an abrupt, high-current electric discharge that occurs in the atmosphere of the Earth and other planets, that occurs in thunderstorms because of vertical air motions and interactions between cloud particles cause a separation of positive and negative charges.

limiting factors

factors that regulate populations using multiple criteria: intrinsic or extrinsic, biotic or abiotic, or density-dependent or density-independent

linear

along a straight line in a positive or negative direction

linear motion

motion forward or backward along a straight-line path

line of best fit

a line plotted on a scatter plot of data which is 'closest to most points' of the plot, a best approximation of a summary of all the points on a scatter plot

lithosphere

is the solid, inorganic outer shell of the Earth

litmus paper

a strip of paper treated with litmus (a powdery substance obtained from lichens, which turns red in acids and blue in bases)

longitude

a measure in degrees of distance east and west of the prime meridian which passes through Greenwich, England

low pressure

a system in which air pressure decreases toward the center, associated with unsettled weather, usually formed by a mass of warm air being forced up by cold air

low pressure system

a region where rising air is leaving less dense air below

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magnitude

a measure of the size of an object

mass

the quantity of matter as determined from its weight or from Newton's second law of motion

matter

material substance that occupies space and has mass

medium

one of the major components of an organism; e.g. blood, fatty tissue, lymph nodes or breath, in which chemicals can be stored or transformed

mercury barometer

an instrument that measures atmospheric pressure using a column of mercury

mesosphere

the region of the atmosphere between 50 km and 90-100 km above the Earth's surface

metabolism

the sum of all the physical and chemical processes by which living organized substance is produced and maintained (anabolism), and also the transformation by which energy is made available for the uses of the organism (catabolism)

meteorologist

a person who studies the Earth's atmosphere and weather systems

methodology

the methods or organizing principles underlying a particular art, science, or other area of study

metronome

a mechanical or digital device used for marking time for musicians

microbes

single-cell organisms so tiny that millions can fit into the eye of a needle

microorganism

an organism of microscopic or submicroscopic size, especially a bacterium or protozoan

models

(physical, mathematical, or conceptual) are simplified representations of real phenomena that facilitate a better understanding of some scientific concepts or principles

molecular compound

is a neutral compound composed of two or more non-metallic elements held together by covalent bonds

molecular mass

also referred to as formula mass -- this is the total mass of a molecule determined by adding the total atomic masses of all of the atoms in the molecule

molecule

the smallest physical unit of an element or compound, consisting of one or more like atoms in an element and two or more different atoms in a compound

momentum

the amount of force or motion in a moving body, the tendency of a moving object to continue moving

monoculture

one crop is grown densely over an extensive area

monsoons

are seasonal winds that blow from land to sea in the winter and from sea to land in the summer. Summer monsoons usually bring heavy precipitation

mortality

is the death rate in a population

motion sensor

a device that uses sound waves to detect motion

mutualistic

living in a symbiotic relationship where both organisms benefit

N

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

natural resources

industrial materials and capacities (as mineral deposits and waterpower) supplied by nature

natality

is the birth rate in a population

neutral

a substance has a pH of 7 and is neither acidic nor basic

neutralization

is the reaction between an acid and a base that produces a salt and water

neutralize

to add an acid to a basic solution or a base to an acidic solution until the result is chemically neutral (pH = 7)

neutron

a subatomic particle having no charge and a mass slightly greater than that of a proton

niche

the position or function of an organism in a community of plants and animals

nimbostratus

a stratus cloud that brings rain

nimbus

rain or snow bearing clouds

nitrates

are compounds that contain a nitrogen atom joined to three oxygen atoms

nitrification

the converting nitrogen in the form of ammonia into the usable form of nitrogen, nitrate. This process is carried on by nitrifying bacteria

nitrites

are compounds that contain a nitrogen atom joined to two oxygen atoms

nitrogen fixation

the conversion of atmospheric nitrogen gas into compounds that are usable by plants, typically nitrate ions or ammonia

nodules

an outgrowth formed on the roots of legumes that house symbiotic bacteria that fix atmospheric nitrogen and provide it to the plant in exchange for carbon

nomenclature

the systematic naming of chemical compounds

nonrenewable resources

a natural resource that cannot be re-made, re-grown or regenerated on a scale comparative to its consumption. It exists in a fixed amount that is being renewed or is used up faster than it can be made by nature.

non-toxic

will not cause serious harm or death

non-uniform motion

motion without a constant speed, the direction or speed changes

nutrient

any substance needed by an organism for proper growth, repair, and function such as nitrogen, oxygen, carbon, water, phosphorus, sulphur, hydrogen

nutrient cycle

the path of an element (nutirent) through an ecosystem

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occluded front

forms when a cold front overtakes a slower-moving warm front

octet rule

the eight-electron arrangement in the outer electron shell of the noble-gas atoms. This structure is held responsible for the relative inertness of the noble gases and the chemical behaviour of certain other elements.

omnivore

is a species of animal that eats both plants and animals as its primary food source

organelle

cell component that performs a specific function

organic

compounds that contain atoms of both carbon and hydrogen; many organic compounds also contain oxygen and nitrogen atoms

organism

a living thing or something that was once alive

organic compounds

are molecular substances that contain carbon, excluding carbonates and oxides

organic pesticide

pesticides derived from living organisms, usually plants, claimed to be environmentally friendly

overexploit

to excessively use or manipulate something or someone to one's advantage

oxidizing/oxidizing reaction

a process that involves the partial or complete loss of electrons or the gain of oxygen

ozone

(O₃)is a gas that consists of three oxygen atoms

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paradigm

is the set of experiences, beliefs and values that constitute a way of viewing reality

parameters

a fact or circumstance that restricts how something is done or what can be done

Pascal

(Pa), a unit of pressure equal to one newton per square metre.

peat

is an accumulation of partially decayed vegetation matter. Peat forms in wetlands called bogs, moors, or muskegs

period

horizontal rows of elements in the periodic table

perpendicular

meeting a given line or surface at right angles

perlite

a natural volcanic glass similar to obsidian but having concentric cracks and a relatively high water content. Used as a lightweight aggregate in its fluffy heat-expanded form in fire-resistant insulation and in soil for potted plants

perspective

aspects of a subject as they relate to each other and the whole, a point of view

pesticide

is a substance or mixture of substances used for preventing, controlling, or lessening the damage caused by a pest

pH scale

indicates the acidity or alkalinity of a solution. It is a logarithmic scale in which a change in pH of 1 indicates a ten-fold change in the acidity or alkalinity

pharmaceutical

a medicinal drug

phenol red

a chemical pH indicator

photogate timer

a timing device used in motion experiments in which light sensitive photocells are attached to a computer

photon

a minute packet of electromagnetic radiation; light comes in discrete packets, called photons

photosynthesis

is the process by which green plants and other producers use energy from the sun, and carbon dioxide and water to produce sugars and oxygen

physical change

a change in the size or form of a substance, which does not change the chemical properties of the substance

physical means

by changing a phase or state of matter -- the creation or separation of a mixture-- or physical deformation (cutting, denting, stretching, etc.) or the change in color by addition of dye

phytoplankton

a photosynthetic microorganism; that is it can make its own food

pinwheel

a toy consisting of vanes of coloured paper or plastic pinned to a stick so that they revolve when blown on

polyatomic ion

is composed of two or more non-metallic atoms bonded together covalently

population

is all the members of a species that are living in the same habitat at a particular time

population density

the number of people living per unit of an area (e.g. per square kilometre); the number of people relative to the space occupied by them

population dynamics

the study of the changes in the numbers, and characteristics of individuals in one or several populations, including the biologcial and environmental processes that influence those changes

population explosion

is a condition when an organism's numbers exceed the carrying capacity of its ecological niche

position

is an object's location relative to a reference point

position-time graph

a graph that shows position on the vertical or y-axis and time on the horizontal or x-axis

potential energy

stored energy or energy of position

precipitate

a solid formed from the combining of two solutions

precipitation

is water that falls to the ground in liquid or solid form

predator

an animal that obtains its food by hunting, capturing and killing its prey

prediction

a statement of the excpected outcome of an experiment

prevailing winds

the predominant wind direction

prey

an animal that is a source of food for a carnivore

primary consumer

an organism that gets its energy from producers (plants).  These are often called herbivores

prime meridian

a reference line for longitude, running from the North Pole to the South Pole and passing through Greenwich, England

probability

the relative degree of certainty that can be assigned to certain events happening in a specified time interval or within a specific sequence of events

producers

any organism which brings energy into an ecosystem from inorganic sources. Most plants and many protists are producers

productivity

refers to a generative source of continuing activity

products

are substances that form in a chemical reaction

properties

qualitities or traits belonging and especially peculiar to an individual or thing

proton

a stable, positively charged subatomic particle in an atom

psychrometer

an instrument used to measure water vapour content in the air; usually made up of two thermometers consisting of a dry-bulb and a wet-bulb

pyramid of biomass

a graphical model that shows the dry mass of organisms at each trophic level of an ecosystem

pyramid of energy

a graphical model that shows the amount of energy available at each trophic level of an ecosystem

pyramid of numbers

a graphical model that shows the numbers of organisms that exist at trophic levels in an ecosystem

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qualitative observations

observations that give descriptive, nonnumeric results e.g. the flame was bright red

quantitative observations

observations that give definite, usually numeric results e.g. the flame was 5 cm high

quaternary consumer

eat tertiary consumers. A consumer on the fourth level of the food chain

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radiant energy

energy traveling in the form of electromagnetic waves

radiation

is the transfer of energy through space by waves

rain

is falling water droplets that have a diameter between 0.5 mm and 5 mm

rain gauge

is a device used to measure the amount of rainfall. Typical units are mm

rate

velocity, speed or time at which something occurs

rate of change

is a measure of how fast a quantity changes per unit time

rate of a chemical reaction

is a measure of how quickly or slowly the reaction occurs

reactants

are substances that undergo change in a chemical reaction

reaction

a process in which one or more substances are changed into others

reactive

participating readily in reactions

readability

an instrument's greatest possible precision of measurement

reducing/reduction reaction

a process that involves  complete or partial gain of electrons or the loss of oxygen

reflect

to throw or bend back (e.g. light, or heat) from a surface

relative humidity

is the percentage of water vapour that is actually in a sample of air compared with the amount of water vapour the air would contain at that temperature if it were saturated

renewable resource

any natural resource (as wood or solar energy) that can be replenished naturally with the passage of time 

resilience

generally means the ability to recover from (or to resist being affected by) some shock, insult, or disturbance

respiration

the process by which organisms exchange gases with its environment

rise

on a graph, the change in y, up or down, the number of units up or down on a graph from a given point to a point on a line

run

on a graph, the change in x, left or right, the number of units left or right on a graph from a given point to a point on a line

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salt

is an ionic compound that is composed of a cation from a base and an anion from an acid; a compound formed by replacing hydrogen in an acid by a metal (or radical that acts like a metal)

saturated

of air, state in which, at any given temperature there is as much water vapour in the air as the air can hold

scalar

a physical quantity that has magnitude (size), but not direction (eg. distance, time, speed)

scientific law

is a statement that summarizes an observed pattern in nature

secondary consumer

the second level of consumers on the food chain. They are known as the meat-eaters and can be carnivores or omnivores

sleet

raindrops that refreeze into ice pellets (frozen raindrops) that bounce upon impact with the ground.

slopes of graphs

slope of a distance-time graph represents the speed of the object

or slope

slope of a speed-time graph represents the acceleration of the object

area under a speed-time graph represents the change in distance of the object

smog

a generic term used to describe mixtures of pollutants in the atmosphere

snow

is frozen water crystals that form below 0°C

solar constant

the amount of radiant energy hitting one square metre of the Earth's outer atmosphere every second; during which the Sun's rays are arriving perpendicular to the Earth's surface

solar energy

energy from the sun converted into thermal or electrical energy

solar radiation

energy that is radiated or transmitted in the form of rays or waves or particles

solute

dissolved particles in a solution

solution

the process by which a solid, liquid, or gaseous substance is homogeneously mixed with a liquid or sometimes a gas or solid

solvent

the dissolving medium in a solution

specific heat capacity

is the amount of energy required to raise the temperature of one gram of a substance one degree Celsius

speed

the rate of change of distance of an object

speed of sound

the speed at which sound travels, 344 m/s

stability

the ability of a system to persist and to remain qualitatively unchanged in response either to a disturbance or to fluctuations of the system caused by a disturbance

stationary front

forms when a cold and warm air mass meet, but neither moves

storm surge

a ridge of sea water as high as 5.5 m created at the centre of a hurricane

stratosphere

the region of the atmosphere between 10 km and 50 km above the Earth's surface

stratus clouds

a low-level, flat, shapeless cloud that forms in many layers formed when air masses meet, when a layer of air is pushed up the side of a mountain range, or by conduction when in contact with a very cool ground surface

stroma

in plants, the protein-rich solution that surrounds the grana

subatomic particle

any of various particles of matter that are smaller than a hydrogen atom. Protons, neutrons, and electrons are subatomic particles.

sustainability

is the ability to meet the needs of the present generation without compromising the ability of future generations to meet their needs

symbol

a letter, figure, or other character or mark or a combination of letters or the like used to designate something

symbiotic

a relationship between different species living in close association with each other

system

a set of interrelated components

synthesis

to make, to manufacture or to combine one or more substances

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tangent line

a straight line that just touches the curve of a graph, the slope of this line is the steepness of the curve at that point

tectonic plates

a series of large plates (like pieces of a giant jigsaw puzzle)that make up the surface of the Earth. These plates are in constant motion travelling at a few centimetres per year

temperature

is a measure of the average speed of molecules. Typical units are °C

temperature inversion

a weather condition in which a 'cap' of warm air traps a layer of cooler air below it

terrestrial

living on or in or growing from land; of or relating to the earth or its inhabitants

tertiary consumer

an organism that eats secondary consumers. A consumer on the third level of a food chain

thermal energy

the total energy of the random motion of particles making up a substance

thermodynamics

is a branch of physics that studies the effects of changes in temperature, pressure, and volume on physical systems

thermometer

is a device used to measure temperature. Typical units are °C

thermosphere

the outer region of the atmosphere, starting at 90-100 km above the Earth's surface

threatened species

is likely to become endangered if factors that make it vulnerable are not reversed

thunder

the crashing or booming sound produced by rapidly expanding air along the path of the electrical discharge of lightning

thunderstorm

is a severe storm several kilometres in diameter created by the rapid lifting of moist warm air which creates a cumulonimbus cloud and which may include lightning, thunder, heavy rain, or hail

thylakoids

flat, membraneous sacs inside the chloroplast that are the sites of light absorption

ticker timer

a timing device which makes a series of dots on a paper tape as it is pulled through a timer

time

duration between two events (Standard Unit is seconds)

titration

is a common laboratory method of quantitative analysis that can be used to determine the concentration of a known reactant. Because volume measurements play a key role in titration, it is also known as volumetric analysis

tornado

a swirling, destructive funnel of rapidly moving air associated with a thunderstorm, created by wind shear, wind speeds from 60 km/h to 500km/h

toxic

could cause serious harm or death

trade wind

winds known for their consistent strength and direction

transition metal

any of the metallic elements that have an incomplete inner electron shell and that serve as transitional links between the most and the least electropositive in a series of elements

transpiration

the process by which water that is absorbed by plants, usually through the roots, is evaporated into the atmosphere from the leaves

triple covalent bond

a bond formed by the sharing of three pairs of electrons (six electrons)

trophic level

identifies an organism's position in the energy flow pyramid of an ecosystem

troposphere

the region of the atmosphere from the Earth's surface up to an altitude of 10 km

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ultraviolet radiation

invisible rays that are part of the energy that comes from the sun that can burn the skin and cause skin cancer

uniform motion

motion at a constant speed in a straight line, without change in speed or direction. A useful equation for uniform motion is
v = Δd/Δt.

uniformly accelerated motion

increasing velocity at a constant rate

updraft

an air movement created by rising war air, particularly in a storm cloud

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vacuum

a space that is completely empty

valence electrons

outer electrons in the outermost orbital of an atom which are most often involved in chemical bonding

valence shell

outermost shell of an atom consisting of the valence electrons

vapour

a visible suspension in the air of particles of some substance; the application of heat to change something from a liquid to a gas

variable

is a quantity whose value may vary over the course of an experiment (including simulations), across samples, or during the operation of a system

vector

a physical quantity that has magnitude (size) and direction (position, displacement, velocity or acceleration)

velocity

how fast the position of an object changes, a vector quantity that includes both speed and direction

velocity-time graph

a graph that shows an object's velocity on the vertical or y-axis and the time on the horizontal or x-axis

viscous

thick and sticky, reluctant to flow, and difficult to stir

volume

the measurement of the amount of space occupied by a substance

vortex

a spiral motion of fluid or air that sucks everything near it toward its centre

vulnerable species

is a species that is at risk due to low or declining numbers in some restricted area of its range

W

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warm air mass

a warm body of air covering a relatively wide area and having horizontally uniform temperature and humidity

warm front

ithe leading edge of a warm air mass, a zone created when a warm air mass overtakes a cooler one; the warm air gently rides up over the trailing end of the cold air mass

water cycle

(hydrological cycle) cyclic movement of water from the Earth's surface to the atmosphere, via evaporation and transpiration, and then back to Earth's surface via precipitation

water soluble

a substance capable of being dissolved in water

weather

the day to day environmental conditions in a location

weather balloon

a helium-filled balloon that carries weather instruments aloft

weather radar

a ground-based system that emits microwaves that in turn are reflected back when they hit a solid or liquid object such as precipitation

weather satellite

an orbiting craft that detects light and infrared radiation from the Earth and then relays that data to ground stations

weed

any plant that is unwanted by humans

wet bulb

a thermometer where the bulb is kept moist

wildlife

wild animals and vegetation, especially animals living in a natural, undomesticated state

wind

air moving from an area of high pressure to an area of low pressure

wind chill factor

The wind chill factor indicates what the temperature would feel like with a wind. It takes into account the cooling effect of wind.

wind currents

a large scale wind system, such as the westerlies, trade winds, equatorial easterlies, etc.

wind direction

the direction from which the wind blows

wind shear

a condition in which the wind blows different directions at different altitudes

wind speed

a measure of the rate that air is moving. Typical units are m/s, km/h, or knots

wind vane

a device used to indicate the direction from which wind is blowing (e.g., a North wind comes from the North)

word equation

identifies the reactants and products in a chemical reaction using only the names of the elements and compounds

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x-axis

the horizontal axis of a two-dimensional Cartesian coordinate system, graph

Y

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y-axis

the vertgical axis of a two-dimensional Cartesian coordinate system, graph

Z

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zooplankton

unicellular heterotrophic organisms that drift in water