1.
Water vapor
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Water vapor, water vapour or aqueous vapor, is the gaseous phase of water. It is one state of water within the hydrosphere, water vapor can be produced from the evaporation or boiling of liquid water or from the sublimation of ice. Unlike other forms of water, water vapor is invisible, under typical atmospheric conditions, water vapor is continuously generated by evaporation and removed by condensation. It is lighter than air and triggers convection currents that can lead to clouds, use of water vapor, as steam, has been important to humans for cooking and as a major component in energy production and transport systems since the industrial revolution. Likewise the detection of water vapor would indicate a similar distribution in other planetary systems. Water vapor is significant in that it can be evidence supporting the presence of extraterrestrial liquid water in the case of some planetary mass objects. Whenever a water molecule leaves a surface and diffuses into a surrounding gas, each individual water molecule which transitions between a more associated and a less associated state does so through the absorption or release of kinetic energy. The aggregate measurement of kinetic energy transfer is defined as thermal energy. Liquid water that becomes water vapor takes a parcel of heat with it, the amount of water vapor in the air determines how fast each molecule will return to the surface. When a net evaporation occurs, the body of water will undergo a net cooling directly related to the loss of water, in the US, the National Weather Service measures the actual rate of evaporation from a standardized pan open water surface outdoors, at various locations nationwide. Others do likewise around the world, the US data is collected and compiled into an annual evaporation map. The measurements range from under 30 to over 120 inches per year, formulas can be used for calculating the rate of evaporation from a water surface such as a swimming pool. In some countries, the evaporation rate far exceeds the precipitation rate, evaporative cooling is restricted by atmospheric conditions. Humidity is the amount of vapor in the air. The vapor content of air is measured with devices known as hygrometers, the measurements are usually expressed as specific humidity or percent relative humidity. This condition is referred to as complete saturation. Humidity ranges from 0 gram per cubic metre in dry air to 30 grams per cubic metre when the vapor is saturated at 30 °C, another form of evaporation is sublimation, by which water molecules become gaseous directly, leaving the surface of ice without first becoming liquid water. Sublimation accounts for the slow disappearance of ice and snow at temperatures too low to cause melting
2.
Gas
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Gas is one of the four fundamental states of matter. A pure gas may be made up of atoms, elemental molecules made from one type of atom. A gas mixture would contain a variety of pure gases much like the air, what distinguishes a gas from liquids and solids is the vast separation of the individual gas particles. This separation usually makes a colorless gas invisible to the human observer, the interaction of gas particles in the presence of electric and gravitational fields are considered negligible as indicated by the constant velocity vectors in the image. One type of commonly known gas is steam, the gaseous state of matter is found between the liquid and plasma states, the latter of which provides the upper temperature boundary for gases. Bounding the lower end of the temperature scale lie degenerative quantum gases which are gaining increasing attention, high-density atomic gases super cooled to incredibly low temperatures are classified by their statistical behavior as either a Bose gas or a Fermi gas. For a comprehensive listing of these states of matter see list of states of matter. The only chemical elements which are stable multi atom homonuclear molecules at temperature and pressure, are hydrogen, nitrogen and oxygen. These gases, when grouped together with the noble gases. Alternatively they are known as molecular gases to distinguish them from molecules that are also chemical compounds. The word gas is a neologism first used by the early 17th-century Flemish chemist J. B. van Helmont, according to Paracelsuss terminology, chaos meant something like ultra-rarefied water. An alternative story is that Van Helmonts word is corrupted from gahst and these four characteristics were repeatedly observed by scientists such as Robert Boyle, Jacques Charles, John Dalton, Joseph Gay-Lussac and Amedeo Avogadro for a variety of gases in various settings. Their detailed studies ultimately led to a relationship among these properties expressed by the ideal gas law. Gas particles are separated from one another, and consequently have weaker intermolecular bonds than liquids or solids. These intermolecular forces result from interactions between gas particles. Like-charged areas of different gas particles repel, while oppositely charged regions of different gas particles attract one another, transient, randomly induced charges exist across non-polar covalent bonds of molecules and electrostatic interactions caused by them are referred to as Van der Waals forces. The interaction of these forces varies within a substance which determines many of the physical properties unique to each gas. A comparison of boiling points for compounds formed by ionic and covalent bonds leads us to this conclusion, the drifting smoke particles in the image provides some insight into low pressure gas behavior
3.
Water cycle
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The water cycle, also known as the hydrological cycle or the hydrologic cycle, describes the continuous movement of water on, above and below the surface of the Earth. In doing so, the water goes through different forms, liquid, solid, the water cycle involves the exchange of energy, which leads to temperature changes. For instance, when water evaporates, it takes up energy from its surroundings, when it condenses, it releases energy and warms the environment. The evaporative phase of the cycle purifies water which then replenishes the land with freshwater, the flow of liquid water and ice transports minerals across the globe. It is also involved in reshaping the geological features of the Earth, the water cycle is also essential for the maintenance of most life and ecosystems on the planet. The sun, which drives the cycle, heats water in oceans. Water evaporates as water vapor into the air, ice and snow can sublimate directly into water vapour. Evapotranspiration is water transpired from plants and evaporated from the soil, the water vapour molecule H 2O has less density compared to the major components of the atmosphere, nitrogen and oxygen, N2 andO2. Due to the significant difference in mass, water vapor in gas form gains height in open air as a result of buoyancy. However, as increases, air pressure decreases and the temperature drops. The lowered temperature causes water vapour to condense into a liquid water droplet which is heavier than the air. A huge concentration of these droplets over a space up in the atmosphere become visible as cloud. Fog is formed if the water vapour condenses near ground level, as a result of moist air, air currents move water vapour around the globe, cloud particles collide, grow, and fall out of the upper atmospheric layers as precipitation. Some precipitation falls as snow or hail, sleet, and can accumulate as ice caps and glaciers, most water falls back into the oceans or onto land as rain, where the water flows over the ground as surface runoff. A portion of runoff enters rivers in valleys in the landscape, runoff and water emerging from the ground may be stored as freshwater in lakes. Not all runoff flows into rivers, much of it soaks into the ground as infiltration, some water infiltrates deep into the ground and replenishes aquifers, which can store freshwater for long periods of time. Some infiltration stays close to the surface and can seep back into surface-water bodies as groundwater discharge. Some groundwater finds openings in the surface and comes out as freshwater springs
4.
Soil
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Soil is a mixture of minerals, organic matter, gases, liquids, and countless organisms that together support life on Earth. Soil is called the Skin of the Earth and interfaces with the lithosphere, the hydrosphere, the atmosphere, the term pedolith, used commonly to refer to the soil, literally translates ground stone. Soil consists of a phase of minerals and organic matter, as well as a porous phase that holds gases. Accordingly, soils are often treated as a system of solids, liquids. Soil is a product of the influence of climate, relief, organisms, Soil continually undergoes development by way of numerous physical, chemical and biological processes, which include weathering with associated erosion. Given its complexity and strong internal connectedness soil has been considered as an ecosystem by soil ecologists. Most soils have a dry bulk density between 1.1 and 1.6 g/cm3, while the particle density is much higher. Little of the soil of planet Earth is older than the Pleistocene and none is older than the Cenozoic, Soil science has two basic branches of study, edaphology and pedology. Edaphology is concerned with the influence of soils on living things, pedology is focused on the formation, description, and classification of soils in their natural environment. In engineering terms, soil is referred to as regolith, or loose material that lies above the solid geology. Soil is commonly referred to as earth or dirt, technically, as soil resources serve as a basis for food security, the international community advocates its sustainable and responsible use through different types of soil governance. Soil is a component of the Earths ecosystem. The worlds ecosystems are impacted in far-reaching ways by the carried out in the soil, from ozone depletion and global warming, to rainforest destruction. Following the atmosphere, the soil is the next largest carbon reservoir on Earth, as the planet warms, soils will add carbon dioxide to the atmosphere due to its increased biological activity at higher temperatures. Thus, soil carbon losses likely have a positive feedback response to global warming. Since soil has a range of available niches and habitats. A gram of soil can contain billions of organisms, belonging to thousands of species, mostly microbial, Soil has a mean prokaryotic density of roughly 108 organisms per gram, whereas the ocean has no more than 107 procaryotic organisms per milliliter of seawater. Since plant roots need oxygen, ventilation is an important characteristic of soil and this ventilation can be accomplished via networks of interconnected soil pores, which also absorb and hold rainwater making it readily available for plant uptake
5.
Stoma
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In botany, a stoma, also called a stomate, is a pore, found in the epidermis of leaves, stems, and other organs, that is used to control gas exchange. The pore is bordered by a pair of specialized cells known as guard cells that are responsible for regulating the size of the stomatal opening. The term is used collectively to refer to the entire stomatal complex, consisting of the paired guard cells and the pore itself. Air enters the plant through these openings by gaseous diffusion, and contains carbon dioxide and oxygen, oxygen produced as a by-product of photosynthesis diffuses out to the atmosphere through these same openings. Also, water vapor is released into the atmosphere through these pores in a process called transpiration, stomata are present in the sporophyte generation of all land plant groups except liverworts. Dicotyledons usually have more stomata on the lower epidermis than the upper epidermis, monocotyledons, on the other hand, usually have the same number of stomata on the two epidermes. In plants with floating leaves, stomata may be only on the upper epidermis. Most tree species have leaves only on the lower surface, size varies across species, with end-to-end lengths ranging from 10 to 80 µm and width ranging from a few to 50 µm. Carbon dioxide, a key reactant in photosynthesis, is present in the atmosphere at a concentration of about 400 ppm, most plants require the stomata to be open during daytime. The air spaces in the leaf are saturated with water vapour, which exits the leaf through the stomata, therefore, plants cannot gain carbon dioxide without simultaneously losing water vapour. Ordinarily, carbon dioxide is fixed to ribulose-1, 5-bisphosphate by the enzyme RuBisCO in mesophyll cells exposed directly to the air spaces inside the leaf. For both of these reasons, RuBisCo needs high carbon dioxide concentrations, which means wide stomatal apertures and, as a consequence, narrower stomatal apertures can be used in conjunction with an intermediary molecule with a high carbon dioxide affinity, PEPcase. Retrieving the products of carbon fixation from PEPCase is in an energy-intensive process, a group of mostly desert plants called CAM plants open their stomata at night, use PEPcarboxylase to fix carbon dioxide and store the products in large vacuoles. The following day, they close their stomata and release the carbon dioxide fixed the previous night into the presence of RuBisCO and this saturates RuBisCO with carbon dioxide, allowing minimal photorespiration. This approach, however, is limited by the capacity to store fixed carbon in the vacuoles. It is not entirely certain how these responses work, however, the basic mechanism involves regulation of osmotic pressure. When conditions are conducive to stomatal opening, a proton pump drives protons from the guard cells and this means that the cells electrical potential becomes increasingly negative. The negative potential opens potassium voltage-gated channels and so an uptake of ions occurs
6.
Evaporative cooler
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An evaporative cooler is a device that cools air through the evaporation of water. Evaporative cooling differs from typical air conditioning systems, which use vapor-compression or absorption refrigeration cycles, Evaporative cooling works by exploiting waters large enthalpy of vaporization. The temperature of dry air can be dropped significantly through the transition of liquid water to water vapor. This can cool air using much less energy than refrigeration, in extremely dry climates, evaporative cooling of air has the added benefit of conditioning the air with more moisture for the comfort of building occupants. The cooling potential for evaporative cooling is dependent on the wet bulb depression, in arid climates, evaporative cooling can reduce energy consumption and total equipment for conditioning as an alternative to compressor-based cooling. In climates not considered arid, indirect evaporative cooling can still take advantage of the cooling process without increasing humidity. Passive evaporative cooling strategies offer the benefits of mechanical evaporative cooling systems without the complexity of equipment. An earlier form of air cooling, the windcatcher, was used in ancient Egypt and they caught the wind, passed it over subterranean water in a qanat and discharged the cooled air into the building. Nowadays Iranians have changed the windcatcher into a cooler and use it widely. A typical design, as shown in a 1945 patent, includes a reservoir, a pump to circulate water over the excelsior pads. This design and this material remain dominant in evaporative coolers in the American Southwest, in the United States, the use of the term swamp cooler may be due to the odor of algae produced by early units. Passive evaporative cooling techniques in buildings, such as cooling towers, have only been developed and studied in the last 30 years. In 1986, two researchers at the University of Arizona, Tucson, W. Cunningham and T. Thompson, constructed the first passive evaporative cooling tower in Tucson, AZ. This performance data from this facility became the foundation of today’s evaporative cooling tower design guidelines. Evaporative cooling is the addition of water vapor into air, which causes a lowering of the temperature of the air and this conversion of sensible heat to latent heat is known as an adiabatic process because it occurs at a constant enthalpy value. Evaporative cooling therefore causes a drop in the temperature of air proportional to the sensible heat drop, Evaporative cooling can be visualized using a psychrometric chart by finding the initial air condition and moving along a line of constant enthalpy toward a state of higher humidity. A simple example of natural evaporative cooling is perspiration, or sweat, secreted by the body, the amount of heat transfer depends on the evaporation rate, however for each kilogram of water vaporized 2,257 kJ of energy are transferred. The evaporation rate depends on the temperature and humidity of the air, vapor-compression refrigeration uses evaporative cooling, but the evaporated vapor is within a sealed system, and is then compressed ready to evaporate again, using energy to do so
7.
Boiling
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Transition boiling is an intermediate, unstable form of boiling with elements of both types. The boiling point of water is 100 °C or 212 °F, boiling water is used as a method of making it potable by killing microbes that may be present. Clostridium spores can survive this treatment, but as the infection caused by this microbe is not water-borne, boiling is also used in cooking. Foods suitable for boiling vegetables, starchy foods such as rice, noodles and potatoes, eggs, meats, sauces, stocks. As a cooking method it is simple and suitable for large scale cookery, tough meats or poultry can be given a long, slow cooking and a nutritious stock is produced. Disadvantages include loss of water-soluble vitamins and minerals, commercially prepared foodstuffs are sometimes packed in polythene sachets and sold as boil-in-the-bag products. Nucleate boiling is characterized by the growth of bubbles or pops on a heated surface, in general, the number of nucleation sites are increased by an increasing surface temperature. An irregular surface of the vessel or additives to the fluid can create additional nucleation sites, while an exceptionally smooth surface, such as plastic. Under these conditions, a liquid may show boiling delay. As the boiling surface is heated above a temperature, a film of vapor forms on the surface. Since this vapor film is less capable of carrying heat away from the surface. The point at which this occurs is dependent on the characteristics of boiling fluid, transition boiling may be defined as the unstable boiling, which occurs at surface temperatures between the maximum attainable in nucleate and the minimum attainable in film boiling. If a surface heating the liquid is significantly hotter than the liquid then film boiling will occur, where a layer of vapor. This condition of a vapor film insulating the surface from the liquid characterizes film boiling, in distillation, boiling is used in separating mixtures. This is possible because the rising from a boiling fluid generally has a ratio of components different from that in the liquid. The elimination of micro-organisms by boiling follows first-order kinetics—at high temperatures it is achieved in time and at lower temperatures. Boiling does not ensure the elimination of all micro-organisms, the bacterial spores Clostridium can survive at 100 °C but are not water-borne or intestine affecting, thus for human health, complete sterilization of water is not required. Though the boiling point decreases with increasing altitude, it is not enough to affect the disinfecting process, boiling is the method of cooking food in boiling water, or other water-based liquids such as stock or milk
8.
Clothes dryer
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Clothes may also be dried by natural evaporation and, if available, sunlight, on an outdoor or indoor clothes line or clothes horse. Many dryers consist of a drum called a tumbler through which heated air is circulated to evaporate the moisture. Using these machines may cause clothes to shrink or become less soft, a simpler non-rotating machine called a drying cabinet may be used for delicate fabrics and other items not suitable for a tumble dryer. Tumbler dryers continuously draw in the cool, dry, ambient air around them, the resulting hot, humid air is usually vented outside to make room for more dry air to continue the drying process. This design makes no effort to recycle the heat put into the load, nevertheless, it is simple and reliable, and therefore has been widely used. Although this may be beneficial in dry conditions, excess humidity from these devices increases likelihood of mold, mildew. Indoor venting may also be against local regulations, gas dryers must always be vented outdoors, as the products of combustion are mixed with the moist air. Building codes and manufacturers instructions usually recommended that dryers vent outdoors, an indoor lint trap kit poses a similar concern of increased humidity within the dwelling. One notable source of heat to pre-heat dryer air is to install ductwork allowing the device to suck hot air from a dwellings attic and these centrifuge machines simply spin their drums much faster than a typical washer could, in order to extract additional water from the load. They may remove more water in two minutes than a heated tumbler dryer can in twenty, thus saving significant amounts of time and energy. Although spinning alone will not completely dry clothing, this additional step saves a worthwhile amount of time, in some cases, dryers may use spin alone. Larger gyms and swimming pools may have small spin dryers for the convenience of exiting patrons, extracting much of the water from a swimsuit means fewer problems in gym bags and later, laundry hampers. Just as in a dryer, condenser or condensation dryers pass heated air through the load. However, instead of exhausting this air, the uses a heat exchanger to cool the air. The dryer air is run through the loop again, the heat exchanger typically uses ambient air as its coolant, therefore the heat produced by the dryer will go into the immediate surroundings instead of the outside, increasing the room temperature. In some designs, cold water is used in the exchanger, eliminating this heating. In terms of use, condenser dryers typically require slightly more power than conventional dryers. Because the heat exchange process simply cools the air using ambient air, it will not dry the air in the internal loop to as low a level of humidity as typical fresh
9.
Matki (earthen pot)
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Matki, is a Hindi word used for an earthen pot. It is used all over India, as well as Pakistan, Bangladesh and Sri Lanka and it has been in use since ancient times and can be found in houses of every class. They are made by the combination of two types of mud clay, the first is taken from the surface of the earth, making a matka takes a considerable amount of time. It is a process of at least 8 days. The clay is mixed with water, shaped, finished, polished, dried and baked in a kiln for 5 days, at last it becomes a completed eastern earthen pot, a home water cooler. The cooling process works through evaporative cooling, capillary action causes water to seep and evaporate from the mini-pores in the pot, taking the heat from the water inside, thus making the water inside cooler than the outside temperature. Hence it is used only during summer and not in winter
10.
Aerosol
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An aerosol is a colloid of fine solid particles or liquid droplets, in air or another gas. Aerosols can be natural or artificial, examples of natural aerosols are fog, forest exudates and geyser steam. Examples of artificial aerosols are haze, dust, particulate air pollutants, the liquid or solid particles have diameter mostly smaller than 1 μm or so, larger particles with a significant settling speed make the mixture a suspension, but the distinction is not clear-cut. In general conversation, aerosol refers to an aerosol spray that delivers a consumer product from a can or similar container. Other technological applications of aerosols include dispersal of pesticides, medical treatment of respiratory illnesses, diseases can also spread by means of small droplets in the breath, also called aerosols. Aerosol science covers generation and removal of aerosols, technological application of aerosols, effects of aerosols on the environment and people, an aerosol is defined as a colloidal system of solid or liquid particles in a gas. An aerosol includes both the particles and the gas, which is usually air. Frederick G. Donnan presumably first used the term aerosol during World War I to describe an aero-solution and this term developed analogously to the term hydrosol, a colloid system with water as the dispersing medium. Primary aerosols contain particles introduced directly into the gas, secondary aerosols form through gas-to-particle conversion, various types of aerosol, classified according to physical form and how they were generated, include dust, fume, mist, smoke and fog. There are several measures of aerosol concentration, Environmental science and health often uses the mass concentration, defined as the mass of particulate matter per unit volume with units such as μg/m3. Also commonly used is the concentration, the number of particles per unit volume with units such as number/m3 or number/cm3. The size of particles has an influence on their properties. A monodisperse aerosol, producible in the laboratory, contains particles of uniform size, most aerosols, however, as polydisperse colloidal systems, exhibit a range of particle sizes. Liquid droplets are almost always nearly spherical, but scientists use an equivalent diameter to characterize the properities of various shapes of solid particles, the equivalent diameter is the diameter of a spherical particle with the same value of some physical property as the irregular particle. The equivalent volume diameter is defined as the diameter of a sphere of the volume as that of the irregular particle. Also commonly used is the aerodynamic diameter, for a monodisperse aerosol, a single number—the particle diameter—suffices to describe the size of the particles. However, more complicated particle-size distributions describe the sizes of the particles in a polydisperse aerosol and this distribution defines the relative amounts of particles, sorted according to size. One approach to defining the size distribution uses a list of the sizes of every particle in a sample
11.
Molecule
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A molecule is an electrically neutral group of two or more atoms held together by chemical bonds. Molecules are distinguished from ions by their lack of electrical charge, however, in quantum physics, organic chemistry, and biochemistry, the term molecule is often used less strictly, also being applied to polyatomic ions. In the kinetic theory of gases, the molecule is often used for any gaseous particle regardless of its composition. According to this definition, noble gas atoms are considered molecules as they are in fact monoatomic molecules. A molecule may be homonuclear, that is, it consists of atoms of one element, as with oxygen, or it may be heteronuclear. Atoms and complexes connected by non-covalent interactions, such as hydrogen bonds or ionic bonds, are not considered single molecules. Molecules as components of matter are common in organic substances and they also make up most of the oceans and atmosphere. Also, no typical molecule can be defined for ionic crystals and covalent crystals, the theme of repeated unit-cellular-structure also holds for most condensed phases with metallic bonding, which means that solid metals are also not made of molecules. In glasses, atoms may also be together by chemical bonds with no presence of any definable molecule. The science of molecules is called molecular chemistry or molecular physics, in practice, however, this distinction is vague. In molecular sciences, a molecule consists of a system composed of two or more atoms. Polyatomic ions may sometimes be thought of as electrically charged molecules. The term unstable molecule is used for very reactive species, i. e, according to Merriam-Webster and the Online Etymology Dictionary, the word molecule derives from the Latin moles or small unit of mass. Molecule – extremely minute particle, from French molécule, from New Latin molecula, diminutive of Latin moles mass, a vague meaning at first, the vogue for the word can be traced to the philosophy of Descartes. The definition of the molecule has evolved as knowledge of the structure of molecules has increased, earlier definitions were less precise, defining molecules as the smallest particles of pure chemical substances that still retain their composition and chemical properties. Molecules are held together by covalent bonding or ionic bonding. Several types of non-metal elements exist only as molecules in the environment, for example, hydrogen only exists as hydrogen molecule. A molecule of a compound is made out of two or more elements, a covalent bond is a chemical bond that involves the sharing of electron pairs between atoms
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