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Training Presentation


Low Aim is a Crime, but not high ambition NCERT Guidance in Schools A need for every Child Today at Kayalpatnam – PowerPoint PPT presentation

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Title: Training Presentation

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

A need for every Child Today at Kayalpatnam
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
  • 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
Dust Appear Reappear
  • Dust is mostly tiny fragments abraded from large
  • 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

Guidance for Children
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
  • 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
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
  • 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
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
Black and White Clothes
  • Black material radiates heat faster than white
    material, and similarly absorbs infrared heat
  • 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
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
  • 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
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 are abandant in dry warm soil, a
    million of them can be detected in a gram of
  • 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
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
    Suns 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
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 Earths surface, you
    would find that it gets much warmer.

Guidance for Children
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
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
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
  • 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
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
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
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
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
  • 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

Guidance for Children
Lemon drops create white spots?
  • Lime juice contains 6 10 per cent of citric
  • 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
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

Guidance for Children
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
  • 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
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 fruits

Guidance for Children
Plants survive without leaves
  • Abscission is a physiological process whereby
    plants shed a part, such as leaf, flower or
  • 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
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
  • 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
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
Visibility in the dark
  • Vertebrates have two types of photosensitive
    cells, rods and cones, so called because of their
  • 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
Eyes glow in dark
  • Birds syrinx (the functional equivalent of our
    larynx or voice box) is much simpler than that of
  • 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
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
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
Run before Jumping
  • Due to Newtons 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
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
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
  • 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
Ants dont 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
  • 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
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
  • As sting touches the surface, a volatile chemical
    (trail pheromone), flows out of a gland (Dufours
    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
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
  • 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
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
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
  • It is to be noted that the charmer first hit the
    ground with the pipe before playing it.

Guidance for Children
Spiders dont 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
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

Guidance for Children
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
  • 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
  • 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
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
  • 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
  • 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
  • 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

Guidance for Children
  • 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
  • Common at puberty and it occurs due to endocrine
    disorders, familial predisposition, unbalanced
    diet and constipation.

Guidance for Children
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
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
  • Diaphragm is located between the chest and the
  • 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
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
  • 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
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

Guidance for Children
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
Burning Sensation using Dettol
  • Tincture, dettol and other similar antiseptics
    act as disinfectants and are corrosive in nature.
  • When these antiseptics are applied on wounds, due
    to their corrosive nature they damage the cell
    proteins in the tissues.
  • This action stimulates the underlying sensory
    nerves leading to a sense of irritation.
  • To reduce the corrosive action, use them in a
    diluted form live adding water to it.

Guidance for Children
Sleepy after heavy meals
  • In the human body the mechanism is such that the
    oxygen we breathe in and the vital nutrients in
    the food that we eat are absorbed by the blood
    and supplied to the different organs.
  • The amount of blood supplied to each organ
    depends on the oxygen and nutrition requirement
    of the tissues of the organ and the importance of
    the function it plays at any given time.
  • Normally one-third of blood goes to liver,
    one-fourth to kidney, one-sixth to brain.
    Remaining goes to the muscles and other parts of
    the body.
  • With heavy meals, digestion of the food is needed
    and so more blood is sent to the stomach wells.
    Automatically the flow of blood to other parts of
    the body, including the brain, is reduced.

Guidance for Children
Yellowing of Urine
  • Yellowing of urine is due to the predominant rise
    in the unconjugated bilirubin in the blood.
  • Administration of certain drugs in the patients
    can also result in the rise of unconjugated
  • Even some common medicines like paracetamol and
    sulfonamide are hepatotoxin. So they cause mild
    damage to the liver cells which results in the
    increase of bilirubin level in the blood.
  • In the case of tonics, yellowing is due to
    excretion of B-complex vitamins. These vitamins
    are water soluble and absorption of these
    vitamins is very rapid. But they are rarely
    stored in liver except vitamin B-12.

Guidance for Children
Vegetables washing and cooking
  • When the cut vegetables are washed in water, the
    water soluble vitamins (B complex and Vitamin C)
    are leached away. So, wash before cutting.
  • When vegetables are cooked, thermal destruction
    of vitamins and nutrients also take place. So,
    over heating of vegetables should be avoided.
  • Frying and roasting is bad as it causes 40 - 60
    per cent nutrient loss.

Guidance for Children
Vomiting while Travelling
  • Giddiness occurs when we lose our sense of
  • The sensations perceived by the eye, inner ear,
    skin, muscles and joints help the body to know
    its stability.
  • When we look down from a great height, abnormal
    visual signs are transmitted to the brain,
    without any corresponding information from other
    parts of the body.
  • While looking out in a fixed direction while
    travelling in a bus, the eye sends fast changing
    visual signals to the brain. Such signals confuse
    the mechanism in the brain and lead to giddiness
    and vomiting.

Guidance for Children
Blind men with improved capabilities
  • Scientists have found that the brain is plastic
    meaning, the brain can rewire itself. This has
    proved beneficial to the handicapped.
  • Researchers have demonstrated the process of
    brain rewiring using a technique called
    transcranial magnetic stimulation in which they
    apply a magnetic field to the skull and induce
    electric currents on the brain.
  • They found that the visual cortex (the part of
    the brain which handles signals from the eye) of
    a blind persons brain does not remain idle
    other senses use it.

Guidance for Children
Atmosphere with stellar bodies
  • Atmosphere of stellar bodies is determined by
    studying the spectrum of the light coming from
    the stellar body.
  • We know that the atmosphere is made of atoms and
  • Each of these atoms and molecules emit light at
    characteristic frequencies or wavelengths which
    are also called signatures. No two elements emit
    light of the same frequency.
  • Researchers use spectroscopic tools to study the
    light coming from stellar objects and identify
    the frequency of components in them.

Guidance for Children
Stars blink but not planets
  • The stars seem to twinkle, because we see the
    stars through the ocean of air, the atmosphere.
    The twinkling is caused by differences in
    temperature in the air.
  • Some layers of air are hotter than others, and
    one layer is always swirling and moving through
    another. These different layers of air bend the
    star light in different ways, and at different
  • Stars near the horizon seem to twinkle much more
    than those high in the sky. This is because the
    light of these stars has to travel a longer path
    through a thicker layer of atmosphere, and thus
    has more chance to become disturb.
  • More rays come to us from the surface of a planet
    than from the surface of a star. The light from
    the planets does not waver as much as that from
    the stars, the wavering of one ray of light is
    counteracted by the wavering of another ray in
    another direction.

Guidance for Children
Refrigerator sound
  • The sound from a fridge is due to the frequent
    switching on and switching off the compressor.
  • The compressor is controlled by a thermostat, a
    device which is generally used to measure
  • When the inside of the fridge reaches a present
    temperature, there is no need to cool it further.
    So, the thermostat sends a signal and cuts the
    power to the compressor to stop its cooling
  • When temperature increases and reaches the
    critical temperature, the thermostat sends a
    signal to restore the circuit and switch on the

Guidance for Children
Cool room with fridge open
  • Open fridge will heat the room.
  • Under normal circumstances, the heat from inside
    the fridge is taken out by the compressor and let
    out in the air behind the fridge.
  • If the fridge is kept open in a closed room, the
    chillness coming out through the front door of
    the fridge is cancelled by the heated air coming
    from behind.
  • In any electrical appliance, a part of the
    electricity supplied is wasted as heat because of
    the principles of thermodynamics. This heat will
    raise the temperature of air inside the room.

Guidance for Children
Automatic wrist watches stop
  • Automatic watches have a different mechanism a
    rotor which can rotate freely (like a free wheel
    in a bicycle).
  • Our hand movements make the rotor rotate and wind
    a coil spring. The rotor frees itself to the
    original position after the winding. As a result
    the rotations of the rotor tighten the spring.
    The watch works as the spring releases very
  • If the watch (spring) is kept idle for some time,
    there is no rewinding of the spring, and so it
    stops functioning.

Guidance for Children
Pressure cooker
  • Principle of a pressure cooker is cooking under
    increased pressure. It is well known that food
    gets cooked fast at high temperatures.
  • There is no possibility of heating the water
    beyond 100 degrees in open vessels. Hence it
    takes a lot of time to cook the food.
  • Boiling point increases with increase in
    pressure. Hence in pressure cookers, the steam in
    not allowed to escape but enclosed with in the
    vessel. As more water is converted into gaseous
    stream, the pressure increases which in a feed
    back mechanism increases the boiling point to
    well beyond 100 degrees enabling fast cooking.
  • Normally the temperature reaches about 120
    degrees inside the pressure cooker.
  • In order that the pressure does not reach very
    high values so as to cause an explosion, a weight
    and safety valve are provided to let out the
    excess stream. Also the body of the cooker is
    made of an alloy which can withstand high

Guidance for Children
Draw more current with low voltages
  • Current and voltage are not always in direct
  • Electrical appliances are divided into two
  • Appliances such as electric irons and electric
    heaters which convert electrical energy into heat
  • Appliances such as motors which convert
    electrical energy into mechanical energy.
  • In first group, the current drawn is proportional
    to the square root of the voltage.
  • In the second group, the current drawn is
    inversely proportional to the applied voltage,
    that is, when the applied voltage is lower, the
    current drawn will be proportionally higher, with
    the mechanical power remaining constant.
  • Motors operating at low voltages burn out because
    they tend to draw unduly large currents which can
    not be carried by the wires wound inside them.

Guidance for Children
Earthing Pin is Bigger
  • Earth wire starts from the metal body of the
    appliance and ends in the earth. So it should
    never come into contact with live wire.
  • In case the earth pin is connected wrongly with
    the live socket, the user touching the appliance
    might receive an electrical shock.
  • Earthing pin is made longer than the other pins,
    so that it gets connected the earth terminal
    first before the other pins (live and neutral)
    make the contact in their respective sockets.
  • In case there is a short circuit, as soon as the
    appliance is plugged in, the current from the
    electrical appliance flows to earth without
    harming the user. Hence it is always safe to
    install thick high tension wires for earthing.

Guidance for Children
High Tension Wires - humming sound
  • Air surrounding the conductors of a high voltage
    overhead transmission line is normally an
  • But at extra high voltages (66,000 volts and
    above), the air in close proximity to the
    conductor tends to break down under the voltage
    stress, along the length of the conductor and
    itself becomes a conductor. This is known as
    corona effect.
  • This effect is seen as bluish violet light and
    audible corona as a hum. Audible corona is
    common. Visual corona requires a higher voltage

Guidance for Children
Electric Line Tester
  • It is used for testing alternating current (AC).
  • In an electric line, phase line gives out AC
    which has both positive and negative components.
  • In the case of a tester, when we touch its metal
    cap, a very small amount of current being tested
    passes through the neon bulb, a high resistance
    and through the body to the earth which is at
    zero potential.
  • In other words the body helps to complete the
    circuit enabling the tester to glow. The high
    resistance inside the tester acts as a safety
    mechanism by restricting the amount of current
    passing through the body.

Guidance for Children
Bird not get electrocuted
  • A bird sitting on a live wire will be
    electrocuted only if electric current passes
    through its body.
  • One wire which we call live will be at a
    potential of 230 volts which is called the phase
    wire and the other one which we call the neutral
    wire will be at a potential of zero volts.
  • Immediately on sitting on the live wire the
    birds potential will also be raised to 230 volts
    and if by an accident it comes in contact with
    the neutral wire or touches it, a current will
    pass through its body from the live wire which is
    at a higher potential to the neutral wire which
    is at zero potential.

Guidance for Children
Fan Wings Slightly Curved
  • Fan wings, also called blades, are curved for
    optimum air circulation which is determined by
    solidity ratio which is the ratio of the area of
    the blades to the area of the disc swept by them.
  • If a flat plate is used as a blade, it will
    provide air circulation no doubt but the
    volumetric flow will be less compared to a blade
    which is suitably curved based on an aerodynamic
  • The cross-section of a blade is in the form of a
    circular arc and is called camber. It will vary
    from the root of the blade to its tip. One can
    see the blade twisted from the root to the tip.

Guidance for Children
Reduce power with slow speed in fans
  • We can save power with the new electronic
    regulators but not with the old regulators based
    on rheostats.
  • Rheostats consume a fixed power all the time. If
    we select the highest speed all the power is fed
    to the fans motor. If a lower speed is selected,
    electric power proportional to selected level is
    fed to the motor and the remaining power tapped
    from the mains is wasted as heat in the rheostat.
    Thats why when we run the fan at slow speeds for
    a long time the regulator becomes hot.
  • New regulators are made up of semiconductor
    device called triac. Depending on the speed
    selected, the electronic regulator draws, from
    the mains, only the required power.

Guidance for Children
Chokes and Starters in Tube lights
  • Tube lights are discharge lamps. To initiate a
    discharge, it requires a high voltage (about 1000
    volts) several times the main voltage (about
    200V). To sustain a discharge it requires only
    about 100 V.
  • Choke in an inductance. When current through an
    inductance is abruptly interrupted it induces a
    high voltage. The interruption is done by the
    starter which works like a switch. The high
    voltage strikes an arc between the filaments at
    the ends of the tube light. Once an arc has
    struck, the choke takes half of the mains voltage
    and leaves the rest to maintain the arc.
  • Choke has a core made of thin laminated silicon
    steel sheets. When the sheets vibrate with the
    power frequency (50 Hz) or its harmonics it
    generates noise.
  • A starter is made of two electrodes one of them
    is a bimetallic strip. When a tube light is
    switched on, the voltage between the two
    electrodes produces a spark.

Guidance for Children
Incandescent light bulbs turn grey
  • The greying of the inner surfaces of incandescent
    bulbs is the result of gradual evaporation of
    tungsten from the filament while the light is on.
    This evaporation eventually makes the filament so
    thin it burns out.
  • To reduce greying, a mixture of nitrogen and
    argon is used today.
  • A small amount of abrasive tungsten powder can be
    placed in the bulb. Shaking it occasionally will
    remove the grey coating from the surface to the
  • Greying can almost eliminated by introducing a
    small amount of halogens iodine and bromine.

Guidance for Children
Shadows with tube light and lamps
  • As light travels only along straight line paths,
    if obstructed by any object, it creates a shadow.
  • Filament bulbs are point sources, that is, the
    light emanates from almost a single point and
    goes out radially in all directions.
  • In the case of filament bulbs, there is no light
    ray falling on the shadowed area and so the
    shadow is harp.
  • If the light from one end of the tube light
    causes a shadow, there is a possibility for the
    shadowed area to be lit by a light rays coming
    from the other end or part of the bulb. Hence the
    shadow is blurred.

Guidance for Children
  • Photocopier is an electromechanical device having
    a photoconductive cylindrical drum made of
    cadmium, selenium or an organic photoconductive
    material. (A photoconductive material changes
    its conductivity under light).
  • Upon switching on the machine, the drum is
    positively charged and the heating section, at
    the exit of the copier, with a teflon coated
    roller is heated to 230 to 320 degrees Celsius by
    a heating lamp.
  • An image of the document is reflected by various
    mirrors and lenses to the drum. Depending on the
    intensity of the light received the
    photoconductive material loses its resistance at
    varying levels on its surface. That is, the
    positive charges on the drum are neutralised
    except in those areas representing the image.
  • This results in a latent charge image on the
    drum. A toner (negatively charged) is then pumped
    to the drum. Based on the charge map the toner
    gets deposited and forms a toner image on the
    drum. The drum then rotates and prints this image
    on the moving paper and fixes it at a high

Guidance for Children
Radio signals with directions
  • In radio sets, the problem of not receiving
    signals in certain directions is felt in the
    medium wave band.
  • This is because for this band they use a coil
    wound on a ferrite rod as the antenna.
  • Ferrite rod is directional in its sensitivity. It
    picks up all signals that come in a direction
    perpendicular to its axis and rejects them if
    they come parallel to its axis.
  • Therefore the reception is entirely based on the
    direction in which they reach the radio set.

Guidance for Children
Gravel on Railway Tracks
  • Gravel used on railway tracks is known as
  • It is used to dissipate the vibration produced by
    trains travelling at high speeds.
  • In effect, the gravel layer acts as a cushion and
    damps the vibrations so that they do not travel
    long distances.
  • If the rails are laid on a solid base, these
    vibrations can travel long distances and lead to
    cracks on the base as well as on nearby buildings.

Guidance for Children
No Sound in Vaccum but Light
  • Sound is a mechanical wave but light is an
    electromagnetic (EM) wave.
  • Mechanical vibrations propagate by the actual
    displacement of physical properties. Each
    particle oscillates about its mean position in a
    synchronized manner ot cause energy propagation
    in a mechanical wave pattern.
  • In EM Waves, electric and magnetic fields
    oscillate about their mean zero in mutually
    perpendicular planes and cause wave motion.
  • Thus EM Waves doesnt need a medium but
    Mechanical waves need a medium.

Guidance for Children
Different Rods in TV Antenna
  • The length of the elements and their arrangement
    depend on the wavelength of the signal (local TV
    station). For good reception, the antennas
    length should be half the wavelength of the
    signal in metres.
  • The gain of the folded dipole antenna alone will
    not be much. To reflect the signal which are not
    intercepted by the dipole, a reflector of length
    more than half lamba is fitted at the rear end.
  • It reflects the electromagnetic waves just as a
    mirror reflects light waves. Normally, only one
    reflector is used because additional reflectors
    do not significantly improve the gain. To boost
    the gain, the signal is directed towards the
    dipole using the director elements which are of
    length less than half lamba.

Guidance for Children
Water Heater Coil Heating Process
  • Molecules of water that are adjacent to the
    heating coil first gets heated and thereby
    becomes less dense.
  • The water of lesser density will move up due to
    which the high density cool water on the surface
    comes down. (Liquid of low density will always be
    at the top than a liquid of high density).
  • This movement of water molecules causes water at
    the upper level to become warm sooner than the
    bottom level though we put the coil at the bottom.

Guidance for Children
Global Positioning System
  • GPS is a system which shows the exact position on
    the earth, anytime in any weather and any where.
  • There are 24 GPS satellites orbiting at 11,000
    nautical miles above the earth.
  • GPS has 3 parts
  • Space segment consists of 24 satellites.
  • User segment consists of receivers which we can
    hold in hand or mount in a car and this gives the
    exact location on the earth.
  • Control segment consists of ground stations that
    make sure that the satellites are working
  • Receiver detects the time signal and calculates
    the distance of the satellite. By getting signals
    from three different satellites and by doing
    mathematical calculations, the receiver is able
    to give the exact position where the receivers

Guidance for Children
Milk Overflows but not water
  • Milk is of water (83 87), protein (3.5),
    sugar (5) and fat (4 7.4).
  • When milk is heated, fat boils lighter than
    water, floats as a creamy layer on the top and
    water vapour, in the form of steam bubbles, is
    trapped under it.
  • Further heating results in the formation of more
    number of bubbles.
  • These bubbles expand and lift the creamy layer
    causing it to overflow. In the case of water, the
    steam bubbles break as they reach the surface.

Guidance for Children
Candle lights a room but no LPG
  • Yellow light in candle is responsible for
    illumination of the room.
  • Combustion (burning of fuel) can be of two types
  • Complete Sufficient quantity of oxygen for the
    fuel to burn. This results in a blue frame and
    the heat generated will be maximum.
  • Incomplete Oxygen supply is insufficient. This
    results in an yellow frame with heat produced is
    lesser than maximum obtainable from the fuel.
  • Candle flame has blue hottest zone surrounding
    the wick, black unburnt volatile fuel and
    yellow flames.
  • Yellow flame has hot carbon particles which get
    heated by hotter zones below and emit light due
    to incandescence.
  • LPG (Liquified Petroleum Gas), which is mostly
    propane and a little butane, is mixed with
    sufficient quantities of air in the burner and
    then burnt to give a blue flame.
  • Propane needs about 25 times its volume for
    complete combustion. The flow of gas in
    controlled and ratio of gas and air is
    maintained. As there is no incandescent zone, the
    flame does not illuminate the room.

Guidance for Children
Information on Audio Video Tapes
  • Information is stored in audio/video tapes by
    magnetizing them. These tapes are actually long,
    thin plastic films coated with a magnetic
    material, mainly iron oxide.
  • Player has a recording head which consists of a
    coil of a wire wound around a circular piece of
    iron with a small gap. Any current passing
    through the wire would produce a magnetic field
    around it.
  • When the tape is run through the small gap
    present in the recording head, the varying
    magnetic field magnetism the particles on the tap
    rearranged their moments in accordance with the
    variation in the input signal.
  • While playing, the tapes is run past the
    recording/playing head which senses the magnetic
    field along the tape. This induces a varying
    current in the coil . This current is amplified
    and fed to the speaker or TV to reproduce the
    original message.

Guidance for Children
Popping Ears in Aeroplane
  • To maintain fuel economy, aircrafts should fly at
    altitudes far in excess of those capable of
    sustaining life.
  • Whereas 5500m is about the maximum altitude at
    which a person can live for any extended period,
    a subsonic passenger jet has the best fuel
    economy when flying at around 12000m.
  • Therefore, aircrafts have to be pressurised the
    interior of a passenger aircraft.
  • All airfields are not at the same altitude.
  • As for ear popping, for our safety and comfort
    the internal pressure is imperceptibly reduced,
    all under computer control, as the aircraft
    climbs. It is gradually increased during descent
    so that, as the aircraft is coming to a stop on
    the runaway, the pressure inside and out is the
    same. Normally, it is sufficient for your ears to
    adjust. If not, pinch your nose and gently but
    firmly increase the pressure in the nasal cavity
    until you feel the pressure equalise.

Guidance for Children
Cola Foam Up
  • Carbonated beverages when opened and released
    from pressure or supersaturated solutions of gas
    with more carbon dioxide dissolved in the
    beverage than would be possible at normal
  • Left alone for two hours, the drink would slowly
    lose the gas and go flat. Sodium chloride
    particles seem to provide an especially good
    surface for gas to collect on, form bubbles and
    quickly rise to the surface and escape.

Guidance for Children
Ornaments of Pure Gold
  • Ornaments could be made of pure gold but would
    get easily pressed out of shape. This is because
    gold is a soft metal, though it is heavy.
  • Gold has high density, over two times that of
    iron, because its atoms are heavier.
  • A steel knife cannot cut glass, but a diamond
    tipped steel knife could, because diamond is
    harder than glass and steel is not. Gold is
    easily scratched.
  • A bit of copper is added to gold, to give the
    ornaments hardness and to prevent distortion.
  • 24 carat means 100 per cent gold. One carat
    represents 100/24 per cent. 22 carat gold means
    91.76 per cent of gold. Rest is copper.

Guidance for Children
Hard Water and Layer on Utensils
  • Water contains dissolved salts of calcium,
    magnesium and often iron in the form of
    bicarbonates, chlorides and sulphates present in
    the Earths crust. When such water is heated, the
    bicarbonates of calcium and magnesium decompose
    evolving carbon dioxide and leave behind
    sparingly soluble carbonates.
  • Bicarbonates of iron interacts with the carbon
    dioxide and water forming sparingly soluble
    ferric hydroxide (brown). These sparingly soluble
    salts form the layer or scales seen in utensils
    and boilers.

Guidance for Children
Cold water extinguish fire faster
  • If we use hot water to extinguish fire, the heat
    absorbed from the source (fire), by a definite
    quantity, to reach its boiling point will be far
    lesser vis-à-vis the same quantity of cold water.
  • Colder the water, faster would be extinction of
    the fire.

Guidance for Children
Boiled Water lose Taste
  • Natural water contains few substances gases like
    oxygen, carbon dioxide, sulphates and carbonates
    of calcium and magnesium, iron, etc that impart
    not only taste but also hardness to it.
  • Due to boiling, the dissolved gases are released
    and hardness is removed. Insoluble carbonates and
    hydroxides are formed which get deposited on the
    surfaces and the bottom of the vessel as scales.
    Their separation from water deprives it of its

Guidance for Children
Air-Cooler and Air-Conditioner
  • Air conditioning system is the system which keeps
    on control and maintain the particular condition
    (this is required temperature and humidity of
    air) in the closed space.
  • It is technically defined as a system which
    controls temperature, humidity, purity and motion
    of air to produce desired effects upon the
    occupants of the space.
  • In case of air cooler, which has the capability
    to cool the air inside the space does not
    maintain particular t
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