WHAT IS A GREENHOUSE?

A greenhouse is also called a glasshouse or a hothouse.  It is a structure where plants – fruits, vegetables, flowers – are grown.  It attracts heat because the sun’s electromagnetic radiation warms the plants, soil, and other components within the greenhouse.  Air is warmed from the hot interior area inside the structure through the roof and wall.

A greenhouse uses a special kind of glass that acts as a medium which selectively transmits spectral frequencies.  Spectral comes from the word “spectrum”. 

In layman’s terms, a spectral frequency can be defined in terms of the following principle:  any object in the universe emits, radiates or transmits light.  The distribution of this light along an electromagnetic spectrum is determined by the object’s composition.