Definitions - k

K Value

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.

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K-Selection

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.

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Kapok

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

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Katabatic Wind

Any wind blowing downslope. Usually cold.

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Kelp

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

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Kerbside Recycling System

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.

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Kettle Hole

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

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Kilowatt-Hour

Solar lighting refers to usage of solar light to charge a rechargeable battery during the day. Then during night time the battery is then used to power the lights. This cycle is usually fully automatic.


The lights are often LED's as they have a high energy to light efficiency and have a long operating life.

This is often used in a garden to provide outdoor lighting to paths and landscaping features. Can also be used for emergency lighting and movement controlled lighting.

If used in a outdoor context do make sure the lights are water proof and designed to cope well with UV exposure. Cheaper lights often fail within 2 years. Sometimes putting a bead of silicone sealant around the edge of the solar panel clear plastic cover can dramatically increase their operational life, as this is where they often fail. 

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Kyoto Protocol

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.

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