Teacher resources and professional development across the curriculum

Teacher professional development and classroom resources across the curriculum

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Science in Focus: Shedding Light: Glossary


A measure of hotness or coldness expressed in one of three temperature scales — Fahrenheit, Celsius, and Kelvin. Temperature indicates the direction that heat energy will flow — from a hotter body to a colder one.

A rotating column of air usually accompanied by a funnel-shaped downward extension of a cumulonimbus cloud and having a vortex several hundred yards in diameter whirling destructively at speeds of up to 500 miles (800 kilometers) per hour.

Tornadoes are complex interactions of temperature, pressure, and humidity.

To change (something) into another form, substance, state, or product; transform sunlight into heat.

A property of materials that allows some light to pass through; some of the light that strikes a translucent object is absorbed and reflected while some passes through.

A tinted window is an example of a translucent object.

A property of materials that allows almost all of the visible light to pass through.

A clear glass window is an example of a transparent object

tropic of Cancer
The parallel of latitude 23°27' north of the equator. The tropic of Cancer is the northern boundary of the Torrid Zone. At the summer solstice (June 21st) the Sun is directly over the Tropic of Cancer.

See Arctic Circle and Antarctic Circle.

tropic of Capricorn
The parallel of latitude 23°27' south of the equator. The tropic of Capricorn is the southern boundary of the Torrid Zone, during the winter solstice (December 22nd) the Sun is directly over the tropic of Capricorn.


See Arctic Circle and Antarctic Circle.

A tropical cyclone occurring in the western Pacific or Indian Oceans.

See cyclone and hurricane.


The leaves of plants which have areas which are white or yellow are said to be variegated. These areas of the leaf lack chlorophyll.

A vertebrate is an animal that possesses a backbone. The main vertebrate groups are: Fish, Amphibians, Reptiles, Birds, and Mammals.

virtual image
An image that does not exist in its perceived location; photons do not travel from, to, or through a virtual image. For example, all images seen in a plane (flat) mirror are virtual.

visible spectrum
A range of photon energy levels that the human eye can detect. The visible spectrum consists of the 'colors of the rainbow' --red, orange, yellow, green, blue, indigo and violet.


warm front
A front along which an advancing mass of warm air rises over a mass of cold air. A front is the area of contact between air masses.

water vapor
The name given to water in the form of a gas. Molecules of water as vapor are about 100 times farther apart than water as a solid (ice) or liquid.

Wind is the movement of air at any velocity measured on the Beaufort scale.

See also Beaufort scale and breeze.


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