Definitions - k

The comparison of thermal conductivity can be measured by the 'k' value. The k value, or Thermal Conductivity, specifies the rate of heat transfer in any homogeneous material. If a material has a k value of 1, it means a 1m cube of material will transfer heat at a rate of 1 watt for every degree of temperature difference between opposite faces. The k value is expressed as 1 W/mK. The lower this value is, the less heat the material will transfer.

Species in stable environments tend to live longer and produce fewer, and sometimes larger, offspring. (K is the constant for carrying capacity in terms of population growth.) This used to be true for whales before their environment was changed. See R-Selection.

Kapok trees produce a fluffy fiber in their seed pods. The kapok fiber is a substitute for down.

Any wind blowing downslope. Usually cold.

Underwater forests of tall brown algae that grow in cool coastal waters.

Where people sort out their recyclable waste, either into a box, bag or separate bin, and this is then collected from people's houses, like the ordinary waste collection.

Depression or pond found in glacial deposits (see Kame Terrace). Left by a chunk of melted glacier.

Air pollution occurs when the air contains gases, dust, fumes or odour in harmful amounts. That is, amounts which could be harmful to the health or comfort of humans and animals or which could cause damage to plants and materials.

The substances that cause air pollution are called pollutants. Pollutants that are pumped into our atmosphere and directly pollute the air are called primary pollutants. Primary pollutant examples include carbon monoxide from car exhausts and sulfur dioxide from the combustion of coal.

Further pollution can arise if primary pollutants in the atmosphere undergo chemical reactions. The resulting compounds are called secondary pollutants. Photochemical smog is an example of this.

International treaty whose aim is to stem global warming, signed in 1997 following negotiations within the U.N.

In December 1997, around 180 nations signed a treaty in Japan, under which 38 industrialized countries committed themselves to reducing emissions of the six greenhouse gases blamed for global warming. The Kyoto Protocol stipulates that, between 2008 and 2012, these emissions should be decreased to an average level 5.2% lower than that of 1990.