Science & Technology | The Canadian Encyclopedia

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  • Macleans

    Plane Crash in Fredericton

    This article was originally published in Maclean’s magazine on December 29, 1997. Partner content is not updated. Like thousands of other Canadians last week, Krista Kitchen was headed home for the holidays. Flying into Fredericton from Toronto aboard Air Canada Flight 646, the 23-year-old University of Western Ontario student was looking forward to Christmas with family and friends.

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  • Article

    Plastics-Processing Industry

    Plastics are based on giant molecules (polymers) which have a structure so ordered that they can be shaped at elevated temperatures and pressures, ie, these long-chain polymers exhibit "plastic flow" when heated.

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  • Article

    Plate Tectonics

    Plate tectonics is the theory proposing that Earth’s outer rocky shell is divided into seven major and several smaller rigid plates. Forces generated by heat losses from the planet’s interior constantly move the plates about. Plate movements, ongoing over millions of years (see Geological History), open and close ocean basins, generate volcanoes, raise mountains, facilitate accumulation of mineral and petroleum deposits, and influence evolution and climate change. Friction between plates prevents steady motion and stores energy that is released in sudden movements, causing earthquakes. This article is the full-length entry about plate tectonics. For a plain-language summary, please see Plate Tectonics (Plain-Language Summary).

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  • Article

    Plate Tectonics (Plain-Language Summary)

    Plate tectonics is the theory that rocky plates divide Earth’s surface. The plates move as Earth releases heat from its interior. The movement of plates creates volcanoes and mountains and causes earthquakes. This article is a plain-language summary of Plate Tectonics. If you are interested in reading about this topic in more depth, please see our full-length entry, Plate Tectonics.

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  • Article


    Platinum (Pt) is the best known of the 6 greyish-white, metallic, platinum group elements, which also include palladium (Pd), iridium (Ir), rhodium (Rh), osmium (Os) and ruthenium (Ru). Platinum and palladium are more commonly used than the other elements in the group.

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  • Article

    Point Amour Lighthouse

    In 1858 the Point Amour Lighthouse was built to help sailors through the dangerous waters of the Strait of Belle Isle between Labrador and Newfoundland.

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  • Article

    Pointe-du-Buisson Archaeological Sites

    Pointe-du-Buisson is a small point of land (21 ha) extending into the waters of Lake St Louis (a widening of the St-Lawrence River) at the convergence of the Ottawa River.

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  • Macleans

    Polar Lander Fails on Mars

    No one knows exactly what the surface of Mars is like, but Robert Zubrin has a pretty good idea. At least some of it, he says, is much like a frozen, god-forsaken corner of the Canadian Arctic called Haughton Crater. The terrain is similar - rough-strewn rock on the floor of a crater 16 km across.This article was originally published in Maclean's Magazine on December 20, 1999

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  • Article

    Polar Vortex

    The polar vortex is a wind pattern surrounding the Earth’s poles. Both the North and South pole have polar vortices spinning around them. In both cases, the rotation is generally cyclonic — counter-clockwise around the North Pole and clockwise around the South Pole. While polar vortices exist year-round, they are strongest during each pole’s winter. Canadians tend to experience the effects of the North Pole’s polar vortex toward the end of winter. At this time, the vortex begins to weaken, and cold, polar air travels further south. Polar vortices are atmospheric phenomena which occur on other planets too, such as Mars, Venus and Saturn.

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  • Article


    Pollution can be defined as the release of any material, energy or organism that may cause immediate or long-term harmful effects to the natural ENVIRONMENT. Pollution was viewed initially as the unsightly mess or visible environmental damage resulting from careless disposal of various materials.

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  • Article

    Pollution Probe Foundation

    Pollution Probe was formed in 1969 by a group of University of Toronto students in an effort to address some of the environmental issues that were without a champion at the time. The organization became a registered charity in 1971.

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  • Article

    Population Genetics

    Population genetics is the area of genetics that studies the distribution of genes (the units of genetic inheritance) and genotypes (the genetic complement at one or more loci), and the mechanisms determining genetic variability within a population.

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  • Article

    Post-Traumatic Stress Disorder (PTSD) in Canada

    Post-traumatic stress disorder (PTSD) is a mental illness that affects individuals exposed to trauma (although not all people exposed to trauma develop PTSD). Studies suggest that over 70 per cent of Canadians have been exposed to at least one traumatic event in their lifetime, and that nearly 1 out of 10 Canadians may develop PTSD at some point in their lives. PTSD can affect adults and children and can appear months or even years after exposure to the trauma.

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  • Article


    Potash is an alkaline potassium compound most commonly used in fertilizers. It refers to a variety of salts produced through mining of minerals and chemical manufacturing. Canada is the world's largest potash producer and exporter.

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  • Article

    Prix du Québec

    In 1922, Athanase David, then secretary of the Province of Québec, created 2 prizes to recognize and encourage the work of Québec writers and scientists. The David Prize was created for literature and the Scientific Prize for research.

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