A greenhouse is a special structure that is designed to regulate the temperature and humidity of the environment inside. There are different types of greenhouses, but they all have large areas covered with transparent materials that capture sunlight and heat. The most common materials used in modern greenhouses for walls and roofs are rigid plastic made of polycarbonate, plastic film made of polyethylene, or glass panes. When the inside of a greenhouse is exposed to sunlight, the temperature increases, providing a sheltered environment for plants to grow even in cold weather.
Victoria amazonica (giant Amazon waterlilies) in a large greenhouse at the Saint Petersburg Botanical Garden
Young tomato plants for transplanting in an industrial-sized greenhouse in the Netherlands
Cucumbers reached to the ceiling in a greenhouse in Richfield, Minnesota, where market gardeners grew a wide variety of produce for sale in Minneapolis, c. 1910
Versailles Orangerie at the Palace of Versailles, France.
Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation, dew, or fog to be present.
Paranal Observatory on Cerro Paranal in the Atacama Desert is one of the driest places on Earth.
A hygrothermograph for humidity and temperature recording
Hygrometer for domestic use, wet/dry psychrometer type
Thermo hygrometer displaying temperature and relative humidity
