Page 98 - The Ontario Curriculum, Grades 9 and 10: Science, 2008 (revised)

THE ONTARIO CURRICULUM, GRADES 9 AND 10 | science
atmosphere. A gaseous mass of air surrounding a celestial body, such as the earth.
atom. The smallest part of an element that can exist.
atomic number. The unique number of protons in one atom of an element.
atomic structure. The configuration of subatomic particles within an atom (e.g., an atom of hydro- gen has the structure of one proton in its nucleus surrounded by one electron).
aurora borealis. The northern lights, produced by the collision of charged particles of the solar wind with molecules in the earth’s atmosphere.
base. A bitter, water-soluble substance capable of many chemical reactions, such as combining with an acid to produce a salt and water; a sub- stance with a pH greater than 7.
big bang theory. The most widely accepted scien- tific theory used to account for the origin of the universe. The theory states that the universe began from an infinitely dense point that ex- panded rapidly to form all matter and energy in the universe.
binary compound. A substance formed from two elements.
bioaccumulation. The process by which chemicals (e.g., pesticides) collect in organisms in progres- sively higher concentrations towards the top of food chains.
biodiversity. The variety of species (types) of organisms at all levels of classification in an eco- system, and the variety of ecosystems, globally or within a specific geographic region.
bioluminescence. Light produced from a bio- chemical reaction in a living organism.
biosphere. The portion of Earth (air, land, water) that supports living organisms.
biotic factors. The living components of an eco- system (e.g., animals, plants, bacteria).
Bohr atomic model. A model of the atom pro- posed by the Danish physicist Niels Bohr, in which protons and neutrons are confined in a dense, positively charged core called the nucleus, surrounded by electrons in specific orbits.
boiling point. The unique temperature at which a particular liquid begins to form bubbles inside the liquid. The boiling point temperature is de- pendent upon the external atmospheric pressure.
carbon footprint. The impact human activities have on the environment in terms of the amount of greenhouse gases produced, measured in units of carbon dioxide.
carbon sink. A naturally occurring reservoir that removes carbon dioxide from the atmosphere. Naturally occurring sinks are oceans and plants, as well as organisms that remove carbon from the atmosphere.
carrying capacity. The maximum population size of a given species that an ecosystem can support without reducing its ability to support the same species in the future.
celestial navigation. The use of the positions of stars to determine location and direction when travelling.
celestial object. Any structure (e.g., a moon, a star, a planet, a nebula) that exists in space.
cell differentiation. A stage of development of a living thing during which specialized cells form.
cell division. A process by which a cell, called the parent cell, divides into two or more cells, called daughter cells. Cell division is usually a small segment of a cell’s cycle.
cell specialization. The process by which cells de- velop from similar cells into cells that have specific functions within a multi-cellular organism.
cell theory. A theory that states that all living organisms are made up of one or more cells, that cells are the basic structural and function- al units in living organisms, and that all cells come from pre-existing cells.
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