Atmospheric Pressure

Important points to remember : 1. Force : Force is required to ( 1 ) move a stationary object ( 2 ) stop a moving object ( 3 ) change the velocity and speed of an object ( 4 ) change the size and shape of an object. Pressure : The force applied on unit area is called pressure. Pressure = force/area The unit of pressure is the newton per square metre ( N / m^2 ) Pressure affects substances in the solid state, liquid state, as well as the gaseous state. A fluid substance exerts equal pressure in all directions. A fluid flows from a region of higher pressure to a region of lower pressure. The pressure exerted by the atmosphere is term as atmospheric pressure. The working of a pump, a spray pump, etc., is based on atmospheric pressure.

Important points to remember : 1. Force : Force is required to ( 1 ) move a stationary object ( 2 ) stop a moving object ( 3 ) change the velocity and speed of an object ( 4 ) change the size and shape of an object. Pressure : The force applied on unit area is called pressure. Pressure = force/area The unit of pressure is the newton per square metre ( N / m^2 ) Pressure affects substances in the solid state, liquid state, as well as the gaseous state. A fluid substance exerts equal pressure in all directions. A fluid flows from a region of higher pressure to a region of lower pressure. The pressure exerted by the atmosphere is term as atmospheric pressure. The working of a pump, a spray pump, etc., is based on atmospheric pressure.

How is land and sea breeze is formed ?

See then..... 1. After sunset, the land near the sea gets cooled faster and to a great extent as compared to the sea water. Hence, the air over the land cools quickly. The sea water does not cool quickly. Hence, the air over sea remains warm and rises. Therefore, the air pressure over the land becomes greater than that over the sea. As a result, a breeze from the land towards the sea is produced. This breeze is called a land breeze. 2. During day time, air over the land near the sea gets heated up faster and to a greater extent than the air over the sea. As a result, the warm air over the land becomes lighter and rises. Hence, the air pressure over the land becomes less. Hence, the air over the sea blows towards the lands. This breeze is called a sea breeze.

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Variations among fishes.

1. Fishes show great variety in their size. Some fishes are tiny while some are giant sized. 2. Some species of fish live in fresh water while some live in saline water. 3. Tail fin of some fish is used for changing directions while swimming, while some fish use the same as organ of defence. 4. Some fishes live for a long period of time as they have long life span, while others may have shorter life span. These are variations seen in the body structure, habitat and life span of diffent fish.

Variations among fishes.

1. Fishes show great variety in their size. Some fishes are tiny while some are giant sized. 2. Some species of fish live in fresh water while some live in saline water. 3. Tail fin of some fish is used for changing directions while swimming, while some fish use the same as organ of defence. 4. Some fishes live for a long period of time as they have long life span, while others may have shorter life span. These are variations seen in the body structure, habitat and life span of diffent fish.

What is that ?

GaneshScience: lacrimal gland

GaneshScience: lacrimal gland: Thelacrimal glandsare paired almond-shaped glands, one for each eye, that secrete the aqueous layer of the tearfilm. They are situated in t...

GaneshScience: What is difference between Plant cell and Animal c...

GaneshScience: What is difference between Plant cell and Animal c...: custom toolbar custom toolbar Plant cell : 1. The cell wall is the outermost covering of plant cell. 2. Cell wall is pre...

What is difference between Plant cell and Animal cell.

Plant cell : 1. The cell wall is the outermost covering of plant cell. 2. Cell wall is present in the plant cell. 3. Vacuoles in plant cell are large. 4. Chloroplastids are present in plant cell. 5. Chlorophyll is present in plant cell. Animal cell : 1. The cell membrane is the outermost covering of animal cell. 2. Cell wall is absent in animal cell. 3. Vacuoles in animal cell are small. 4. Chloroplastids are absent in animal cell. 5. Chlophyll is absent in animal cell.

What is difference between Plant cell and Animal cell.

lacrimal gland

Thelacrimal glandsare paired almond-shaped glands, one for each eye, that secrete the aqueous layer of the tearfilm. They are situated in the upper, outer portion of each orbit, in the lacrimal fossaof the orbit formed by the frontal bone. [ 1 ]Inflammation of the lacrimal glands is called dacryoadenitis. The lacrimal gland produces tears which then flow into canals that lead to the lacrimal sac. From this sac, the tears drain through the lacrimal ductinto the nose. Anatomists divide the gland into two sections. The smallerpalpebral portionlies close to the eye, along the inner surface of the eyelid; if the upper eyelidis everted, the palpebral portion can be seen. The orbital portion contains fine interlobular ductsthat unite to form 3–5 main excretory ducts, joining 5–7 ducts in the palpebral portion before the secreted fluid may enter on the surface of the eye. Tears secreted collect in the fornix conjunctiva of the upper lid, and pass over the eye surface to the lacrimal puncta, small holes found at the inner corner of the eyelids. These pass the tears through the lacrimal canaliculion to the lacrimal sac, in turn to the nasolacrimal duct, which dumps them out into the nose. [ 2 ] Microanatomy The lacrimal gland is a compound tubuloacinar gland, it is made up of many lobulesseparated by connective tissue, each lobule contains many acini. The acini contain only serous cells and produce a watery serous secretion. Each acinus consists of a grape-like mass oflacrimal gland cellswith their apices pointed to a central lumen. The central lumen of many of the units converge to form intralobular ducts, and then unite to from interlobular ducts. The gland lacks striated ducts. Innervation The parasympatheticnerve supplyoriginates from the lacrimal nucleusof the facial nervein the pons. Just distal to the geniculate ganglion, the facial nerve gives off the greater petrosal nerve. This nerve carries the parasympathetic secretomotor fibers through the pterygoid canal, where it joins the deep petrosal nerve(containing postganglionic sympathetic fibers from the superior cervical ganglion) to form the nerve of the pterygoid canal( vidian nerve). This nerve travels through the pterygoid canal to the pterygopalatine ganglion. Here the fibers synapse and postganglionic fibers join the fibers of the maxillary nerve, which travels through the inferior orbital fissure. Once it has traversed this opening, the parasympathetic secretomotor fibers branch off with the zygomatic nerveand then branch off again, joining with the lacrimal branch of the ophthalmic division of CN V, which supplies sensory innervation to the lacrimal gland along with the eyelid and conjunctiva. The sympatheticpostganglionic fibersoriginate from the superior cervical ganglion. They travel as a periarteriolar plexus with the middle meningeal artery, before they merge and form the deep petrosal nerve, which joins the greater petrosal nervein the pterygoid canal. Together, greater petrosal and deep petrosal nerves form the nerve of the pterygoid canal (vidian nerve) and reach the pterygopalatine ganglion in the pterygopalatine fossa. In contrast to their parasympathetic counterparts, sympathetic fibers do not synapse in the pterygopalatine ganglion, having done so already in the sympathetic trunk. However, they continue to course with the parasympathetic fibers innervating the lacrimal gland. Blood supply The lacrimal artery, derived from the ophthalmic arterysupplies the lacrimal gland. Venous blood returns via the superior ophthalmic vein.

GaneshScience: Construction of Dry cell.

GaneshScience: Construction of Dry cell.: custom toolbar custom toolbar We alway's use a small cell, called dry cell. But have we imagined how does it work, whats se...

GaneshScience: Wonderful and Highly flammable Marsh Gas.

GaneshScience: Wonderful and Highly flammable Marsh Gas.: custom toolbar custom toolbar Why is Marsh Gas ? What is its use ? How it is produced ? Its scientific and chemicalogical infor...

GaneshScience: Electro Magnetisms and its types.

GaneshScience: Electro Magnetisms and its types.: custom toolbar custom toolbar I would not like to take your 'amulya' (precious) time to share value less life. Magnet...

GaneshScience: The construction and functions of electric doorbel...

GaneshScience: The construction and functions of electric doorbel...: custom toolbar custom toolbar Every time when we goes to frnds house or to any relatives house We always enjoy.........'tri...

GaneshScience: Carbon and its Allotropes.

GaneshScience: Carbon and its Allotropes.: custom toolbar custom toolbar Carbon has three allotropes discovered till now i] Diamond ii] Graphite iii] Fullerene But what ...

GaneshScience: How soil is made ?

GaneshScience: How soil is made ?: custom toolbar custom toolbar Soil formation is slow, time taking, and takes millions of year to form 1-5 cm layer of soil. The...

GaneshScience: How soil is made ?

GaneshScience: How soil is made ?: custom toolbar custom toolbar Soil formation is slow, time taking, and takes millions of year to form 1-5 cm layer of soil. The...

GaneshScience: Uses of Animal

GaneshScience: Uses of Animal: custom toolbar custom toolbar Uses oe Animals : a. Food : Milk and meat. b. Farm work : Help in the farm work which involves ph...

GaneshScience: Bleaching Powder

GaneshScience: Bleaching Powder: custom toolbar custom toolbar The white powder which is generally sprinkled to disinfect any place which is not clean is also...

GaneshScience: s-BLOCK ELEMENTS

GaneshScience: s-BLOCK ELEMENTS: custom toolbar custom toolbar Flame Test : 1. Alkali metal : The alkali metals and their salts impart characteristics colour ...

GaneshScience: s-BLOCK ELEMENTS

GaneshScience: s-BLOCK ELEMENTS: custom toolbar custom toolbar S.No. Atomic Properties Alkali metal 1. Outer electronic configuration ns^1 2. Oxidation nu...

GaneshScience: s-BLOCK ELEMENTS

GaneshScience: s-BLOCK ELEMENTS: custom toolbar custom toolbar Physical properties of alkali metals. S.NO. Physical properties Alkali metal 1. Density i] Al...

GaneshScience: s-BLOCK ELEMENTS

GaneshScience: s-BLOCK ELEMENTS: custom toolbar custom toolbar Physical properties of alkali metals. S.NO. Physical properties Alkali metal 1. Density i] Al...

GaneshScience: s-BLOCK ELEMENTS

GaneshScience: s-BLOCK ELEMENTS: custom toolbar custom toolbar Atomic properties of Alkaline earth metals. S.No. Atomic Property Alkaline earth metals. 1. O...

GaneshScience: s-BLOCK ELEMENTS

GaneshScience: s-BLOCK ELEMENTS: custom toolbar custom toolbar Atomic properties of Alkaline earth metals. S.No. Atomic Property Alkaline earth metals. 1. O...

GaneshScience: s-BLOCK ELEMENTS

GaneshScience: s-BLOCK ELEMENTS: custom toolbar custom toolbar Atomic properties of Alkaline earth metals. S.No. Atomic Property Alkaline earth metals. 1. O...

GaneshScience: Diff. bet^n Algae and Fungi

GaneshScience: Diff. bet^n Algae and Fungi: Algae : 1. In algae, chlorophyll is present. 2. The algae are autotropic. 3. Most of the algae are useful. 4. Antibiotics cannot be prepa...

GaneshScience: Diff. bet^n Algae and Fungi

GaneshScience: Diff. bet^n Algae and Fungi: Algae : 1. In algae, chlorophyll is present. 2. The algae are autotropic. 3. Most of the algae are useful. 4. Antibiotics cannot be prepa...

Diff. bet^n Virus and Bacteria.

Virus : 1. Virus does not have cellular structure. 2. Virus does not have cytoplasm and cell organelles. 3. Virus can be observed only through electro microscope. 4.Viruses are smaller than bacteria. 5.Virus may have DNA or RNA as its genetic material. 6. There is covering of protein around the viral cell. 7. Viruses cannot be killed by antibiotics. 8. All the types of viruses are harmful. Bacteria : 1. Bacteria have cellular structure. 2. Bacteria have cytoplasm, cell membrane and free chromosomes. 3. Bacteria can be observed under a compound microscope. 4. Bacterial DNA and RNA both are present in bacterial cells. 5. Bacteria are larger than viruses. 6. There is covering of cell wall around the bacterial cell. 7. Bacteria can be killed by a specific antibiotic. 8. All bacteri are not harmful. Some of them are useful too.

Diff. bet^n Algae and Fungi

Algae : 1. In algae, chlorophyll is present. 2. The algae are autotropic. 3. Most of the algae are useful. 4. Antibiotics cannot be prepared from algae. 5. Algae are producers in the food chains. Fungi : 1. In fungi, chlorophyll is absent. 2. The fungi are saprophytic. 3. Most of the fungi are harmful. Only few are useful. 4. Antibiotics are prepared from fungi 5. Fungi are decomposers in the food chain.

Diff. bet^n Algae and Fungi

Algae : 1. In algae, chlorophyll is present. 2. The algae are autotropic. 3. Most of the algae are useful. 4. Antibiotics cannot be prepared from algae. 5. Algae are producers in the food chains. Fungi : 1. In fungi, chlorophyll is absent. 2. The fungi are saprophytic. 3. Most of the fungi are harmful. Only few are useful. 4. Antibiotics are prepared from fungi 5. Fungi are decomposers in the food chain.

s-BLOCK ELEMENTS

Atomic properties of Alkaline earth metals. S.No. Atomic Property Alkaline earth metals. 1. Outer electronic configuration ns^2 2. Oxidation number and valency The IP1 of these metals are much lower than IP2 and thus it appears that these metals should form univalent ion rather than divalent ions but in actual practice, all these give bivalent ion. 3. Atomic and Ionic radii The atomic and ionic radii of alkaline earth metal are smaller than corresponding alkali metals. Reason higher nuclear charge (Zeff) On moving down the group size increase, as value of n increases. BeMg>Ca>Sr>Ba IE1 of alkali metal < IE1 of alkaline earth metal. IE2 of alkali metal > IE2 of alkaline earth metal. Reason IE1 of alkaline earth metal is large due to increased nuclear charge in alkaline earth metal as compared to alkali metal but IE2 of alkali metal is large because second electron in alkali metal is to be removed from cation which has already acquired noble gas configuration. 5. Electropositivity Due to low IE they are strong electropositive but not as strong as alkali metal because of comparatively high IE. The electropositivity increases down the group. Order = Be Mg^+2 > Ca^+2 > Sr^+2 > Ba^+2 7. Electronegativity ¡] Their electronegativities are also small but are higher than that of alkali metals. ii] Electronegativity decrease from Be to Ba

s-BLOCK ELEMENTS

Atomic properties of Alkaline earth metals. S.No. Atomic Property Alkaline earth metals. 1. Outer electronic configuration ns^2 2. Oxidation number and valency The IP1 of these metals are much lower than IP2 and thus it appears that these metals should form univalent ion rather than divalent ions but in actual practice, all these give bivalent ion. 3. Atomic and Ionic radii The atomic and ionic radii of alkaline earth metal are smaller than corresponding alkali metals. Reason higher nuclear charge (Zeff) On moving down the group size increase, as value of n increases. BeMg>Ca>Sr>Ba IE1 of alkali metal < IE1 of alkaline earth metal. IE2 of alkali metal > IE2 of alkaline earth metal. Reason IE1 of alkaline earth metal is large due to increased nuclear charge in alkaline earth metal as compared to alkali metal but IE2 of alkali metal is large because second electron in alkali metal is to be removed from cation which has already acquired noble gas configuration. 5. Electropositivity Due to low IE they are strong electropositive but not as strong as alkali metal because of comparatively high IE. The electropositivity increases down the group. Order = Be Mg^+2 > Ca^+2 > Sr^+2 > Ba^+2 7. Electronegativity ¡] Their electronegativities are also small but are higher than that of alkali metals. ii] Electronegativity decrease from Be to Ba

s-BLOCK ELEMENTS

Physical properties of alkali metals. S.NO. Physical properties Alkali metal 1. Density i] All are light metals. ii] Density increases down the group but K is lighter than Na. Order = LiNa>K>Rb>Cs B.P = Li>Na>K>Cs>Rb 4. Specific heat It decreases from Li to Cs. Li>Na>K>Rb>Cs

s-BLOCK ELEMENTS

Physical properties of alkali metals. S.NO. Physical properties Alkali metal 1. Density i] All are light metals. ii] Density increases down the group but K is lighter than Na. Order = LiNa>K>Rb>Cs B.P = Li>Na>K>Cs>Rb 4. Specific heat It decreases from Li to Cs. Li>Na>K>Rb>Cs

s-BLOCK ELEMENTS

S.No. Atomic Properties Alkali metal 1. Outer electronic configuration ns^1 2. Oxidation number and valency (i) These elements easily form univalent +ve ion by losing loosely solitary ns^1 electron due to low IP value. 3. Atomic and Ionic radii Increases down the group, because value of n ( principal quantum number ) increases. Order = Li < Na < K < Rb < Cs. 4. Ionisation Energy As size increases, I.E. decreases down the group ( so Cs have lowest I.P. ) Order = Li > Na > K > Rb > Cs 5. Electropositive character or metallic character Alkali metals are strongly electropositive and metallic. Down the group electropositive nature increase so metallic nature also increases. I.E. M ---> M^+ + e^- Metallic Nature : Electropositive character § 1/ I.P. Order = LiNa>K>Rb>Cs

s-BLOCK ELEMENTS

Flame Test : Alkaline earth metals : Calcium, strontium, and barium impart characteristic brick red, crimson red and apple green colours respectively to the flame. In flame the electrons are excited to higher energy levels and when they drop back to the ground state, energy is emitted in the form of visible light. The electrons in beryllium and magnesium are too strongly bound to get excited by flame. Hence, these elements do not imparts any colour to the flame . The flame test for Ca , Sr and Ba is helpful in their detection in qualitative analysis and estimation by flame photometry . The alkaline earth metals like those of alkali metals have high electrical and thermal conductivities which are typical characteristics of metals. Metals ( colour of flame ) : Be ( no colour ), Mg ( No colour ), Ca ( brick red ), Sr ( crimson red ), Ba ( apple green ). Next topic : Atomic properties, physical properties, and reaction of group 1 element (alkali metals ). To be continued ..............

s-BLOCK ELEMENTS

Flame Test : 1. Alkali metal : The alkali metals and their salts impart characteristics colour to an oxidizing flame. This is because the heat from the flame excites the outermost orbital electron to a higher energy level. When the excited electron comes back to the ground state, there is emission of radiation in visible region. Alkali metals can therefore, be detected by the respective flame tests and can be determined by flame photometry or atomic absorption spectroscopy. These elements when irradiated with light, the light energy absorbed may be sufficient to make an atom lose electron. Metal ( colour of flame ) : Li ( crimson red ) , Na ( yellow ) , K ( violet / lilac ) , Rb ( red violet ) , Cs ( blue ). Next topic : FLAME TEST for alkaline earth metals. To be continued ..........

Bleaching Powder

The white powder which is generally sprinkled to disinfect any place which is not clean is also used to disinfect water. You must have experienced the typical strong odour from well water during rainy season. The white powder is called bleaching powder and the strong odour is due to chlorine gas which is released when bleaching powder is added to water. When dry slaked lime reacts with chlorine gas, it forms bleaching powder Ca(OH)2(S) + Cl2(g) ----> CaOCl2(s) + H2O(l) When bleaching powder comes in contact with atmospheric CO2 gas, it forms CaCO3(S) and Cl2(g). This Cl2(g) helps in the bleaching action on cotton in the textile industry, wood pulp in paper factories and washed clothes in laundry. Bleaching powder acts as an oxidizing agent in many chemical reactions and is useful in preparation of organic solvent chloroform which is also used as an anesthetic. Bleaching powder is also known as chloride of lime and the chlorine generated is known as "available chlorine" The bleaching powder brands available in market are classified on the basis of percentage of available chlorine present in them. To be continued . . . . .