Knowledge for Children Low Aim is a Crime, but not high ambition NCERT ‘Guidance in Schools’

1. Knowledge for Children • Low Aim is a Crime, but not high ambition • NCERT ‘Guidance in Schools’ A need for every Child Today at Kayalpatnam

2. CFCs damage Ozone Layer ? • Chloroflurocarbons (CFC) used by refrigrants, coolants, cleaning agents, etc are main eaters of ozone present in atmosphere. • Highly unstable, an ozone molecule readily splits when hit by ultravoilet radation. Energy of life-damaging UV rays is thus converted into harmless heat and never reaches the earth. This process generates Oxygen atom and Oxygen molecule, which in an ongoing cycle, recombine to form new ozone molecules. • When CFCs go upward to stratosphere and get struck by ultra violet rays, it releases chlorine atom, which attacks an ozone molecule, pulls away one of the three oxygen and forms a chlorine monoxide molecule thus destroying the ozone molecule. • Oxygen atoms from the new chlorine monoxide molecule is pulled away by free oxygen atoms freeing the chlorine atom to restart the cycle. Guidance for Children

3. Dust – Appear & Reappear • Dust is mostly tiny fragments abraded from large things. • Dust knows no borders. • Dust cloth may simply stir up dust. • Charged particles of dust are attracted to surfaces with the opposite charge. • An antistatic spray may help by providing a very thin layer of insulation between the opposite charges. Guidance for Children

4. Age of Fossils • Atoms of same element having same atomic number but different mass number are called isotopes. • Radio active isotope of carbon is 146C which has a half life period of 5730 years. Half life period of a radio active substance is defined as the time required for half of its atoms to disintegrate. • The radio isotope of carbon is continuously produced in the atmosphere by the action of cosmic rays on atmospheric hydrogen. • Plants and animals absorbs 146C with natural carbon 126C. In living beings, the ratio of 146C/126C is a constant when a plant or animal dies the 146C disintegrates without being replaced. Hence by determining the ratio 146C/126C in fossil the age is determined. This method is called “Carbon dating”. Guidance for Children

5. Height of Mountains Measured • The method used is known as “Triangulation”. • If one knows one side and two angles of any triangle (or two sides and one angle), one can find out the rest of its measurement. • One side of the triangle is usually a level piece of ground between two landmarks. • The third landmark is the apex of the triangle. The angle it makes with each of the first line is measured. • Instrument for measuring these angle is called a transit. The transit works vertically which is called levelling as there is a spirit level at the base of the instrument that indicates when it is in level. By raising the sight to any landmark or a mountain, the same process of measuring angles can be done and the length of one side (the height) can be measured. Guidance for Children

6. Lava is hot ? • Magma is predominantly a molten silicate saturated with gases that are dissolved in it. • Due to high pressure existing in deeper part of the earth where volatile compounds are in a dissolved state. within magma, diminishing its viscosity and increasing the degree of its mobility and chemical activity. • Volcanism unites all the processes connected with the outflow on the earth surface. • Liquid products of volcanic eruptions are represented by lava. Guidance for Children

7. Black and White Clothes • Black material radiates heat faster than white material, and similarly absorbs infrared heat faster. • Although it is true that dark objects radiates heat more effectively than light-coloured ones, the amount of heat radiated from a body is proportional to its absolute temperate raised to the power of 4. • In Summer, it would be better to wear white as the benefit of black clothes radiating heat away quickly would not outweigh the disadvantage of them absorbing infrared heat more quickly. Guidance for Children

8. Rainfall – Measure ? • A simple rain gauge which any one can use to measure rain at his place consists of a funnel (3 to 4 inches in diameter) fitted into a bottle (about 1 litre capacity) to collect the rain water and a measuring cylinder. • An air-vent is to be provided to prevent accumulation of rain water in the funnel in case of heavy down pours. • Rain gauge is kept on the ground without obstructions. • If the area of opening of the funnel is 80cm2 then for 1cm of rainfall the volume of water would be 80cm2 x 1cm that is 80cm3. • If the total volume of rain water (in cm3) collected, over a specified period, is divided by 8, we get the rainfall in mm in that place over the given period. Guidance for Children

9. Smell after Rain • Smell immediately after a shower is due to certain volatile chemical compounds released by a group of soil-inhibiting bacteria called streptomycetes. • Streptomycetes are abandant in dry warm soil, a million of them can be detected in a gram of soil. • They release compounds such as geosmin and 2 methyl isoborneol when wetted by rain water after a long dry spell. • Thus we get the odour only after the first rain of the rainy season. The smell can be felt in newly ploughed lands also. Guidance for Children

10. Rainbow Formation • When the Sun shines after a shower, we often see an arc of beautiful colours in that part of the sky opposite to the Sun. • This is due to reflection and refraction of the Sun’s rays as they fall on drops of rain. As a ray passes into a drop of rain, the water acts as a tiny prism. The ray is bent, or refracted as it enters the drop and is separated into different colours. As it strikes the inner surface of the drop it is further refracted and dispersed. Guidance for Children

11. Mountain Tops are Cooler & not hot? • Air is a poor absorber of sunlight. • Sun heats the Earth which is a better absorber, and the Earth then heats the air close to it. • Hot air rises because it is less dense than surrounding cooler air at the same pressure. • As it rises, a mass of hot air expands because the ambient pressure is less. This expansion cools the air, so the temperature of a thermal bubble decreases with increasing altitude until it reaches an equilibrium. • If you climb 40Km above the Earth’s surface, you would find that it gets much warmer. Guidance for Children

12. Sound in Thunder • Warm, wet air surges upwards into the sky and cools dramatically forming thunderstorms. • Some of the water inside the clouds freeze and strong air currents make the ice and water droplets bump together. • This knocks tiny charged particles called electrons from the ice and so there is a build-up of electric charge. This charge is released by a stroke of lightning. The lightning heats the air around it to an incredible 30,000C. • We hear lightning first and then thunder because light travels faster than sound. • By counting the seconds between the lightning and thunder and dividing by three we get the distance to the storm in Kilometres. Guidance for Children

13. Finger Cool Faster • Our body is like a container of heat. • The amount of heat per unit volume (say, every cubic centimetre) of the body is approximately the same. • But the fingers and nose have a greater surface area per cubic centimetre than other parts of the body and so they cool down faster. • As soon as heat is delivered to the fingers it escapes through the surface. But the rest of the body does it slower and so are a little hotter than the fingers. Guidance for Children

14. Coconut Oil Freeze in Winter • Oils are liquid fats. Fats are esters of carboxylic acids which are either saturated (do not contain double bond) or unsaturated (contain one or two double bond). These esters are derived from a single alcohol called glycerol and are glycerides. • Fats with greater percentage of unsaturation tend to be in liquid state and fats with greater percentage of saturation tend to be in solid state at room temperature. • Coconut oil contains nearly 91 per cent of saturated fatty acids. Still, it is liquid at room temperature because of the presence of more number of short chain (C12 and C14). • Because of the greater percentage of saturation, coconut oil can be solidified at low temperature and becomes solid during winter when the temperature falls below 20 degree centigrade. Guidance for Children

15. Water in Mud Pot remains cool • Mud pots contain many minute pores through which water can slowly ooze out. • These pores increase the surface area of water and consequently increase evaporation. • For water to evaporate it requires some energy while it takes as heat from the water itself. • This results in lowering the temperature of the water in the pot. • Water never becomes ice because the system is not a closed system and so it can take up heat from its surroundings. Guidance for Children

16. Drops are Spherical ? • Liquid drops tend to be in a state of minimum surface energy which is directly related to the surface area. • The force, surface tension, which is trying to hold the droplet together, therefore tries to reduce the surface area of the drop. • Mathematically only a sphere has the smallest surface area for a given volume, compared to other geometric shapes. Guidance for Children

17. Sunflower facing Sun • Due to Phototropism. • Phototropism is a growth-mediated response of a plant to simulation by visible light. The response is stimulated by a hormone called auxin present in the stem. • Auxins promote lengthwise growth of plants. Guidance for Children

18. Lotus leaf does not get wet • Lotus leaf does not get wet due to outlayers of cells in the epidermal layer of leaves. • They contain cellulose, which get converted by cutin by the process of cutinization and form an impermeable membrane on the cell wall known as cuticule. • Cuticle, is a layer of wax-like substances which are simple lipids containing one molecule of fatty acids esterified with one molecule of long chain alcohols instead of glycerol. • A molecule of wax consists of odd number of carbon atoms ranging from C25 to C35. These are highly insoluble in water & chemically inert because these do not have double bonds in their hydrocarbon chains. Hence waxes from a protective covering. Guidance for Children

19. Lemon drops create white spots? • Lime juice contains 6 – 10 per cent of citric acid. • Cement is a complex mixture of calcium silicates and calcium aluminates. • When drops of lime juice fall on the floor, a chemical change takes place. • One of the products is calcium citrate which gives a white colour on these spots. Guidance for Children

20. Cut Apple turns Brown • Apple contains an enzyme known as polyphenol oxidase (it is a copper containing enzyme). • When the fruit is cut, this enzyme becomes reactive as it comes into contact with air. It reacts with the sugar present in the fruit and results in the formation of brown colour on the cut surface. • If cut apple is dipped in an ascorbic acid solution browning of the cut surface can be prevented as the acid inhibits activity of the enzyme. Guidance for Children

21. Temperature affect ripening bananas • Temperature changes can delay or hasten the ripening of banana. • Banana is a tropical fruit; adapted to ripen quickly at a certain stage of its development and at a particular temperature and humidity. It continues to ripen after harvest, with more and more of its starch converted into sugars by the action of enzymes. • When harvested, a banana contains about 20 percent starch and only 1 percent sugar. By the time the fruit is ripe, the proportions are reversed. • Banana releases comparatively large quantities of ethylene gas to help itself ripen; the gas will even ripen other fruit put in a bag with a ripening banana. Guidance for Children

22. Mango ripens in rice tin • During ripening, a number of enzyme-assisted reactions take place inside the fruits. The list includes softening of tissues, hydrolysis, changes in pigmentation, flavour and respiration rate, and conversion of carbohydrates and organic acids into fruit sugars. These changes are induced by ethylene which is also called a ripening hormone. • It has been found that during ripening, ethylene production goes up. An ethylene-forming mechanism and breaking of the insensitiveness to ethylene are attained only when fruits reach a certain physiological age. • When unripe fruits are kept inside a sack or tin of rice, the time needed to attain this critical physiological age is shortened. It could be that the fruit to totally cut off from light which promotes yellowing. The ethylene produced in the fruit also diffuses rapidly through the fruit’s tissues. Guidance for Children

23. Plants survive without leaves • Abscission is a physiological process whereby plants shed a part, such as leaf, flower or fruit. • This is promoted by a plant hormone called abscisin produced by leaves and fruits. • Extreme temperatures limit the metabolic activities such as respiration, of plants. Such a reduction, consequently necessitates only a low level of photosynthetic activity. • Less Energy required could be got from photosynthetic activity of a few green cells, present in the terminal regions, after all the leaves fell. Guidance for Children

24. Red parts in Sugarcane • Red portions in the stem of cane is due to a fungal disease called red-rot caused by the organism Glomerella tucumanensis. The organism attacks during the conidial stage (imperfect stage). • When the affected canes are split open, the tissues of the internode which are normally white or yellow-white will become red in one or more internodes usually near the base. Guidance for Children

25. Trees Reduce Air Pollution • Trees act as sink for carbon dioxide. Through photosynthesis they synthesize carbohydrate using Carbon Dioxide, water and sunlight. • Trees release oxygen, which is needed by other living organisms. • They act as barriers or curtains for dust through the settlement on the dense foliage of trees. Guidance for Children

26. Visibility in the dark • Vertebrates have two types of photosensitive cells, rods and cones, so called because of their shape. • The rods, which are long and fat, contain large amounts of visual pigment and they mediate vision under dim illumination (scotopic vision). • The cone cells, which are relatively small, mediate daylight vision (photopic vision) and colour sensation. • In nocturnal animals, the retina is mainly made of rod cells. • Rhodopsin, a photosensitive pigment, present in rods is decolourised by photons (light particles) and slowly regenerated in the dark. This ensures better vision for them in dim light. Guidance for Children

27. Eyes glow in dark • Birds’ syrinx (the functional equivalent of our larynx or voice box) is much simpler than that of humans. • Some birds with more rudimentary syrinx can become more proficient in creating sound. • In birds, the syrinx is located at the bottom of the trachea. Sound is produced at the syrinx as air flows and the volume is controlled by muscles in the trachea. The sounds are then emitted with little or no modulation. • Human vocalisations originate from the larynx at the top of the trachea. The larynx is more complex and produces relatively simple sounds. Guidance for Children

28. Eagles fly with flat wings • Eagles adopt an energy-saving flight mode called gliding. Their broad wings and broad rounded tail enable them to exploit thermals in the air. • Thermals are upward air currents in the atmosphere caused by the absorption of heat, from the sun or load, by the air. • The birds flap their wings slowly and laboriously in the air in wide circles, but once they catch the rising air they begin to soar effortlessly without even a single beat up to a point where the warm air has cooled and stopped rising. • From this point, they start gliding down to another thermal, which they spot by seeing other groups of rising raptors or perhaps by their delicate sensitivity to even minute changes in air currents. • Their primary feathers are spread out to obtain the maximum advantage from the rising air. Guidance for Children

29. Blinking Of Eyes • Blinking keeps the front of eyeball clean. • Blinking is done by means of muscles in the eye lids and the cleansing by tears. • The tears are secreted in a little gland and carried along to the eye and when our eyelids open and close the tears are poured over the front of eye and they wash away any particles of dust or any other harmful substances. Guidance for Children

30. Run before Jumping • Due to Newton’s law of motion: All objects living and non-living, have inertia – a tendency to remain in its present condition. • If a body is at rest, it will have a tendency to remain at rest in future also. In the same way, if a body is moving, it will have a tendency to continue its movement at a later time. • If we stand at a point and jump, we will not be able to cover a good distance because our body will try to remain standing (be at rest), and we will have to spend a lot of energy (or more power) to jump long distances. • Thus, we run before jumping before saving. Guidance for Children

31. Bees Find Their Way • Information about the source of food is informed to others during round dance or waggle dance. • Round dance is going in small circles, clockwise or anticlockwise, alternately. • Waggle dance is tracing a figure of eight. • Round dance is used if the food is of short distance [say 100m]. Waggle dance is used if the food is far away. • They use round dance or waggle dance to find their way. Alternatively, they can return to the hive by remembering the angles of triangles formed by the position of the hive, the sun and bee though this may vary with time. • Bees can also perceive polarisation of sunlight and thus use the sun as a compass. Guidance for Children

32. Ants find their way to hidden sweets • Antennae, the two hair-like structures on the head of the ants, help them in locating sweets. • These chemoreceptors help them to perceive smell and taste through minute sensilla, or sensory cells. • If sweets are wrapped in paper bags or any other wrappers having minute holes, the odour carried by the air will be sensed by the sensilla. • If the antenna are removed, ants cannot identify the smell and distinguish them from other foods. Guidance for Children

33. Ants don’t get hurt when they fall • Fall of a body is controlled by gravitational attraction of the Earth. • Heavier object is attracted more than a lighter object. • This attractive force is opposed by an upward thrust (resistance) offered by air on the body. This resistance also depends on the surface area of the object. That is, if the surface area is more, the resistance is also more. • In the case of an ant, the force of gravity is almost balanced by air resistance and so it is able to land safely. Guidance for Children

34. Ants go in a line • Once an ant find an abundant source of food, it returns to the nest with a sample of food. While returning to the nest, it presses its abdomen to the ground and at frequent intervals extrudes its sting, the tip of which is drawn lightly over the ground surface, much like a pen drawing a thin line. • As sting touches the surface, a volatile chemical (trail pheromone), flows out of a gland (Dufour’s gland), associated with the sting. In this way, the ant draws an invisible chemical line from the source of food to the nest. • Since the chemical is highly volatile, the trail remains only for a short time. Hence, all ants constantly draw the line over and over again. Guidance for Children

35. Houseflies increase in Summer • A single female may lay eggs 4 to 6 times and each time each female lays 120 to 160 eggs. They lay their eggs in clusters on compost, waste heaps, manure and dumps. • The condition required for laying eggs are moisture and favourable temperature. The eggs hatch in 8 to 24 hours depending on the temperature. • The whitish larvae moult twice to become the familiar white maggots in 7 days. • The maggots transform into quiescent reddish brown pupa from which the adult flies emerge after 5 days if the temperature is optimal. Summer provides all the favourable conditions. Guidance for Children

36. Bulges when mosquito bites • Bulging is mainly due to histamine. • It is widely distributed in the tissues, the richest source being the mast cells that are normally present in the corrective tissues adjacent to the blood vessels. • Preformed histamine is present in mast cell granules and is released by mast cell degranulation process which in response to the stimulus caused due to irritation at the site of the bite. • This histamine causes dilation of the arterioles and increases vascular permeability venules. This in turn causes venular endothelial contraction and widening of the interendothelial cell junctions, where the extra vascular fluid accumulates causing inflammation. Guidance for Children

37. Do Snakes Hear ? • Snakes are deaf. • Snakes actually respond to vibrations produced on the ground and not to the sound waves produced by the mahudi [Snake Charmer], in the air. • Snakes do not have ears, instead they have a long bony road called columella auris that extends from fenestra ovalis to the quadrate bone. It is this bone which helps the snake to detect the vibrations. • It is to be noted that the charmer first hit the ground with the pipe before playing it. Guidance for Children

38. Spiders don’t get caught in their web • Spiders secrete an oil on its legs that prevent it from sticking to their own web. • Silk, made up of proteins, secreted by the silk glands, are made into fibres as thin as a thousandth of a millimetre. • The proteins are water soluble when secreted, but when made into a fibre, some physical and chemical changes take place, and so, after a while the fibre becomes tough and does not dissolve in water. • Spider at first makes the radials from the centre and then the spiralling threads. There may be 10-60 turns in a web. To capture an insect, spider places a small glue droplets throughout, except at the place where it rests. • The vibrations of the captured insect are sensed by the spider. Guidance for Children

39. Blood Clotting • Blood has the ability to clot or coagulate, when it is withdrawn from the body. • In the blood vessels, the blood remains in a fluid condition: shortly after being withdrawn, it becomes viscid and gelatinous and sets into a firm, jelly-like mass. • Clot consists almost entirely of red corpuscles entangled in a network of fine fibrils or threads, composed of a substance called fibrin. It also contains platelets and plasma. • Certain substances promote coagulation (procoagulants) and others inhibit coagulation (anticoagulants). Guidance for Children

40. Blood Grouping • Blood types is based on the different types of antigens present on the surface of the red blood cells (RBC). • Four Groups: A, B, AB, O. The letters stand for the type of antigen present on the red blood cells. • The corresponding antibodies are carried in the plasma and if the person has a particular antigen in his red cells, he can not have the corresponding antibody, since agglutination would occur. Thus group A contains antigen A and antibody anti-B. • Group AB has antigens of A & B and not antibodies of either type. • Group O has no antigens and antibodies anti-A and Anti-B. • If the blood protein [first discovered in blood of Rhesus monkey] is present in the blood cells, then the blood cells are called Rh positive and if they are absent, it is called Rh negative. Guidance for Children

41. Air we breathe out is seen in cold day • The air we exhale on a cold day is visible because of the formation of dew. • The air we exhale has water vapour and carbondioxide. • Our exhale air is about 40oC but outside atmosphere is about 10oC. • Cold air cannot hold as much water vapour as warm air. Dew is formed when air is cooled to the point where it cannot hold all its water vapour, so the moisture in it begins to condense forming tiny water droplets. The temperature at which the moisture in the air begins to condense is called dew point. • From 40 to 10 degree centigrade, it is cooled to below the dew point but above its freezing point. Hence the tiny water droplets float in the air and are visible. Guidance for Children

42. Myopia • Myopia is defined as an eye defect where the image of the object falls before the retina of the eye. • The person affected with myopia cannot see distant objects clearly, but can see objects that are close to him. • Myopia is also known as short sight. • Three types: • Congenital Myopia: Since birth. • Simple or developmental myopia: Defect increases usually as age advances. • Pathological or degenerative myopia: Condition rapidly increases and there may be high myopia upto 20 D. Guidance for Children

43. Cramps • Cramp can occur due to a localised muscle spasm. • Pain or uneasiness is caused by nervous irritation due to accumulation of some metabolites or chemicals in that area. • Massage, external compression of muscle, improves blood supply. It helps in washing away these metabolites and thus relives the cramp. • However, not all cramps can be relieved by massage. Guidance for Children

44. Dandruff • Dandruff is a condition of excessive scales of the scalp. • There are two varieties: Dry and Greasy. • Dry: The scales are fine, thin, white or greyish, and dry or slightly greasy. • Lacks lusture; Mild to moderate itching; Scales will fall freely on the shoulders. • Occurs more in winter than in summer. • Exaggeration of normal exfoliation of the horny layer of the epidermis. • Greasy: Both the scale and integument are oily. • Extends to eyebrows, eyelids, beard and others. • Basic defect in this case is over production and/or change in composition of the sebaceous secretion. • Common at puberty and it occurs due to endocrine disorders, familial predisposition, unbalanced diet and constipation. Guidance for Children

45. Antidandruff Shampoo Work • Dandruff is thought to be caused by overgrowth of yeast such as Pityrosporum ovale which live on normal skin. • Antidandruff shampoos work by three mechanisms: • Ingredients such as coal tar are antikeratostatic and they inhibit keratinocyte cell division. • Detergents in the shampoo are keratolytic: they break up accumulation of scale. • Antifungal agents such as ketoconazole inhibit growth of yeast itself. Other components such as selenium sulphide also inhibit yeast growth and therefore scaling. Guidance for Children

46. Cold & Flu in Winter • Rhinivirus, which is responsible for up to 40 per cent of clods, culture better at a temperature of 32 degrees C rather than the normal body temperature of 37 degrees C. However, 32 degrees C is the normal temperature of the lining of the nose, which is good news for the virus. • Children and teenagers are far more susceptible to infection as the immune system learns how to combat more infections as they get older as have been exposed to more of the 200 or so viruses responsible for the common cold. • Densely packed nurseries, schools and college provide an ideal breeding ground for viruses which then spread out into the community aided by the cold damp weather. Guidance for Children

47. Hiccups • Diaphragm is located between the chest and the stomach. • While inhaling air this diaphragm goes down and presses the stomach due to which the lungs are filled with air. • While exhaling air, the diaphragm goes up and the air comes out from the lungs. • Thus the diaphragm goes up and down and the process of respiration continues incessantly without making any sound. • Two sudden and involuntary contractions within the diaphragm cause hiccups. You can get hiccups if you eat too much or too fast or if you eat victuals disagreeable to your system. Guidance for Children

48. Blocking Nose While Crying • Tear fluid is secreted by a lacrimal gland seen bulging the conjunctiva (muscous membrane covering the eyeball and lining the eyelids) • Tear passes through numerous ducts into the conjunctive sac, aided by ocular muscle contraction. • From there it reaches the lacirne sac and through the lacrimal duct it is drained into the nasal cavity, (Lacrimal duct is an anatomical drainage canal connects the corner of the eye to the lower surface of the nasal cavity). Guidance for Children

49. Itching when wound heals • Itching is due to the release of a chemical substance, called histamine, which stimulates nerve endings. • Histamine is a decarboeylated form of amino-acid histidine, a powerful vasodilator present in animal tissues. • When tissues become inflamed, histamine is released from mast cells in the tissues. • During healing, the number of basophils in WBCs increase. Basophils contain relatively large amounts of histamine. • Histamine from the basophils and from the surrounding cells diffuse into the skin nearby and stimulates the nerve endings, which leads to itching. Guidance for Children

50. Wound becomes Septic • The reaction between metal sheets and air or other oxidising agents are the cause for rusting. • Rust is a form of oxidised metal film forms on metallic surfaces. • When these rusted metals make wounds, the micro-organisms gain entrance into the wounds as spores and germinate under unaerobic condition particularly when the wound is deep or if the oxygen tension is low due to the presence of other aerobic micro-organisms. • During the metabolism these clostridia excretes toxins, that are pathogenic for human beings, the wound become septic and if left untreated results in death. Guidance for Children