Training Presentation

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
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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
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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
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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
  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
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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
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
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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
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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
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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
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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
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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
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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
  tissues.

Guidance for Children
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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
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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
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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
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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
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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
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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
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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
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
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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
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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
  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
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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 (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
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 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
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
51
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
52
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
53
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
  bilirubin.
• 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
54
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
55
Vomiting while Travelling

• Giddiness occurs when we lose our sense of
  balance.
• 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
56
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
57
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
  molecules.
• 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
58
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
  angles.
• 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
59
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
  temperature.
• 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
  function.
• When temperature increases and reaches the
  critical temperature, the thermostat sends a
  signal to restore the circuit and switch on the
  compressor.

Guidance for Children
60
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
61
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
  slowly.
• 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
62
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
  pressures.

Guidance for Children
63
Draw more current with low voltages

• Current and voltage are not always in direct
  proportion.
• Electrical appliances are divided into two
  groups
• Appliances such as electric irons and electric
  heaters which convert electrical energy into heat
  energy.
• 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
64
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
65
High Tension Wires - humming sound

• Air surrounding the conductors of a high voltage
  overhead transmission line is normally an
  insulator.
• 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
  stress.

Guidance for Children
66
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
67
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
68
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
  principles.
• 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
69
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
70
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
71
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
  glass.
• Greying can almost eliminated by introducing a
  small amount of halogens iodine and bromine.

Guidance for Children
72
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
73
Photocopier

• 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
  temperature.

Guidance for Children
74
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
75
Gravel on Railway Tracks

• Gravel used on railway tracks is known as
  ballast.
• 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
76
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
77
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
78
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
79
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
  properly.
• 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
  located.

Guidance for Children
80
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
81
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
82
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
83
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
84
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
  pressure.
• 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
85
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
86
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
87
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
88
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
  taste.

Guidance for Children
89
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