The green house effect is a process by which thermal radiation from a planetary surface is absorbed by atmospheric greenhouse gases,
and is re-radiated in all directions. Since part of this re-radiation
is back towards the surface and the lower atmosphere, it results in an
elevation of the average surface temperature above what it would be in
the absence of the gases.
Solar radiation at the frequencies of visible light largely passes through the atmosphere to warm the planetary surface, which then emits this energy at the lower frequencies of infrared
thermal radiation. Infrared radiation is absorbed by greenhouse gases,
which in turn re-radiate much of the energy to the surface and lower
atmosphere. The mechanism is named after the effect of solar radiation
passing through glass and warming a greenhouse,
but the way it retains heat is fundamentally different as a greenhouse
works by reducing airflow, isolating the warm air inside the structure
so that heat is not lost by convection.
Earth’s natural greenhouse effect makes life as we know it possible.
However, human activities, primarily the burning of fossil fuels and
clearing of forests, have intensified the natural greenhouse effect,
causing global warming.
(Wikipedia)
Global warming cause :
- Burning natural gas, coal and oil -including gasoline for automobile engines-raises the level of carbon dioxide in the atmosphere.
- Some farming practices and land-use changes increase the levels of methane and nitrous oxide.
- Many factories produce long-lasting industrial gases that
do not occur naturally, yet contribute significantly to the enhanced
greenhouse effect and "global warming" that is currently under way.
- Deforestation also contributes to global warming. Trees use
carbon dioxide and give off oxygen in its place, which helps to create
the optimal balance of gases in the atmosphere. As more forests are
logged for timber or cut down to make way for farming, however, there
are fewer trees to perform this critical function.
- Population growth is another factor in global warming,
because as more people use fossil fuels for heat, transportation and
manufacturing the level of greenhouse gases continues to increase. As
more farming occurs to feed millions of new people, more greenhouse
gases enter the atmosphere.
3 ways to reduce global warming :
- Use Green energy for industrial like use wind, waterfall, ocean wave, sunlight or geothermal for power plant.
- Stop deforestation & start greening for decrease solar radiation absorbed by earth surface
- Convert fossil fuel transportation vehicle to electric or green energy for decrease level carbon dioxide amount in atmosphere
A Green house is a building with different types of covering materials, such as a glass or plastic
roof and frequently glass or plastic walls; it heats up because
incoming visible solar radiation (for which the glass is transparent)
from the sun is absorbed by plants, soil,
and other things inside the building. Air warmed by the heat from hot
interior surfaces is retained in the building by the roof and wall. In
addition, the warmed structures and plants inside the greenhouse
re-radiate some of their thermal energy in the infrared spectrum, to
which glass is partly opaque, so some of this energy is also trapped
inside the glasshouse which plants are grown. Key factors which may be controlled include temperature, levels of light and shade, irrigation, fertilizer application, and atmospheric humidity.
TEMPERATURE
Ventilation
is one of the most important components in a successful greenhouse. If
there is no proper ventilation, greenhouses and their plants can become
prone to problems. The main purposes of ventilation are to regulate the
temperature to the optimal level, and to ensure movement of air and thus
prevent build-up of plant pathogens (such as Botrytis cinerea) that prefer still air conditions. Ventilation also ensures a supply of fresh air for photosynthesis and plant respiration, and may enable important pollinators to access the greenhouse crop.
IRRIGATION & FERTILIZER APPLICATION
Hydroponics is a subset of hydroculture and is a method of growing plants using mineral nutrient solutions, in water, without soil. Terrestrial plants may be grown with their roots in the mineral nutrient solution only or in an inert medium, such as perlite, gravel, mineral wool, expanded clay pebbles or coconut husk.
Researchers discovered in the 18th century that plants absorb essential mineral nutrients as inorganic ions
in water. In natural conditions, soil acts as a mineral nutrient
reservoir but the soil itself is not essential to plant growth. When the
mineral nutrients in the soil dissolve in water, plant roots are able
to absorb them. When the required mineral nutrients are introduced into a
plant's water supply artificially, soil is no longer required for the
plant to thrive. Almost any terrestrial plant will grow with
hydroponics. Hydroponics is also a standard technique in biology
research and teaching.
Aeroponics is the process of growing plants in an air or mist environment without the use of soil or an aggregate medium (known as geoponics). The word "aeroponic" is derived from the Greek meanings of aero- (air) and ponos (labour). Aeroponic culture differs from both conventional hydroponics and in-vitro (plant tissue culture)
growing. Unlike hydroponics, which uses water as a growing medium and
essential minerals to sustain plant growth, aeroponics is conducted
without a growing medium. Because water is used in aeroponics to transmit nutrients, it is sometimes considered a type of hydroponics.(Wikipedia)
