Saturday, 30 April 2016
Monday, 29 February 2016
The Age of Plastics
Ø Give
some examples of fibres. (cotton, wool, silk, jute, nylon etc)
(answer
may vary, accept all correct answers)
Ø Is
cotton natural or synthetic fibre? (natural fibre)
Ø What is synthetic
fibre?
fibres
such as cotton, wool, silk, jute etc. are
obtained
from plants or animals. Such fibres are known as natural fibres.
· Inform
that, fibres which are synthesised by human beings are known as
synthetic
or man-made fibres. There are several synthetic fibres such as rayon,
nylon, acrylic, polyester
etc.
Ø How
is the necklace formed? (by joining the beads together)
Ø What
is the synthetic fibre made up of?
Ø How is the
synthetic fibre formed?
many beads
are joined together in a
string to
form a long necklace. Similarly, a synthetic fibre is a long chain of
several
small parts joined together.
· Inform
that, a substance formed by joining of many small parts is known as
polymer (poly = many;
-mer = part). Each part in a polymer is known as a
monomer
(mono = one; -mer = part).
each bead
can be considered as a monomer and the necklace as
polymer
many small units come together and are joined chemically to form a
polymer. This process of
formation of a polymer is known as polymerization
Ø From
which source cotton fibre is obtained? (cotton plant)
Ø From
which source synthetic fibres are obtained?
· Explain
that, synthetic polymers are manufactured in industries mainly from the
by-products
of crude oil and petroleum, also known as petrochemicals.
· Inform
that, the raw materials can also be obtained from fossil fuels, such as,
coal and natural gas.
Ø What
is the most commonly used synthetic fibre? (nylon)
Ø How
it is formed?
· Inform
that, Nylon is arguably the most commonly used synthetic fibre in the
world.
Inform that, nylon is completely synthesised in industries without using any
natural raw materials. It is
thus considered the first fully synthetic fibre.
What is
the difference between natural and synthetic fibres? (natural are
obtained
from plants or animals and the synthetic fibres are synthesised by
human
beings)
Ø Do you think
natural fibre is better than synthetic fibre or vice-versa
Ø Name
two polyester fibres. (terylene and polyethylene terepthalate)
Ø You
must have heard about /or wore Terrycot /Terrywool clothes. From which
fibres terrycot is made up
of? (terylene and cotton)
Our Flora and Faunas
Ø
Have you ever noticed that, some
specific bird species are seen in
Wildlife sanctuaries or national
parks in summer seasons only?
(yes/no)
ØWhy these birds are seen only in specific months in these
wildlife sanctuaries or national parks.
What is reforestation?
(Reforestation is the process of
turning a destroyed forest back into a forest)
ØWhat is species?
(A species is a group of living
organisms consisting of similar
individuals who are capable of
interbreeding and reproducing a fertile
offspring of the same species.)
ØGive example of any five living organisms that can be
classified under the category ‘flora’.
ØGive example of any five living organisms that can be
classified under the category ‘fauna’.
(answer may vary, accept all correct
answers)
ØWhat is deforestation? (Deforestation is cutting down or
clearing of forest areas.)
ØWhat causes deforestation?
Deforestation may take place either due
to human activities or due to natural causes.
ØWe cut down forest and get wood required for fuel. How do we
get coal and
petroleum products?
(by coal mining or oil mining processes
we dig out coal and petroleum products)
Mining is generally carried out in
forest areas and huge amounts of forest area are destroyed for this activity.
.This leads to habitat destruction
and death of most of floral and faunal species of those forest areas.
ØWe are benefited by clearing forest,as weget fuel,
food,medicine,space for making houses, raw
materials for making furniture as
well as for industries.
Do you think the practice of cutting
forest have any negative effects on
human beings? If yes, how?
ØAs we now know the devastating effects of destruction of
forest and its resources.
How can we conserve our forest and
wildlife resources?
ØIn which countries do you find dogs and cats?
(in almost all the countries of the
world)
ØWhere do you find kangaroos? (Australia)
ØWhere do you find polar bears? (Arctic regions)the
categorieson which IUCN is classifying living organisms.The status and
existence of various plants, animals and other species in nature is assessed
from time to time by different organisations. The Red
Data Book is the source book in
which a record of all endangered plants,animals and other species is
maintained. There are different red data books forplants, animals and other
species.
ØWhy do you think there is a need of Red data book?
The Red Data Book provide scientific
information on the status of different species in order to preserve and manage them,
ØWhat is endemic species?(endemic species is one that is only
found in that region and nowhere else in the world)
ØWhat are extinct species? Give example of a species that is
now extinct.
(Plant and animal species which once
existed on Earth but are no longer seen are called extinct
species.Example: dodo)
Find out the meaning of each of the
following IUCN categories:
üExtinct in the wild(EW)
üNear threatened(NT)
üLeast concern(LC)
üData deficient(DD)
üNot evaluated(NE)
ØHow many of you have been to any wildlife sanctuary or
national park?
(instruct the students to raise
their hands who have been to any wildlife
sanctuary or national park)
ØHave
you ever noticed that, some specific bird species are seen in wildlife sanctuaries
or national parks in summer seasons only? (yes/no)
ØWhy
these birds are seen only in specific months in these wildlife sanctuariesor
national parks?, many living organisms move from
their natural habitat to faraway places during aparticular time of year. This
seasonal movement of living organisms is called migration.,
Friday, 12 February 2016
The Control Systems
The Control Systems
·
What
is coordination?Ø
(The ability of the body to use its different parts together smoothly and
efficiently as well as to interact with the external environment is called
coordination.)
·
What
is nervous system made up of?
(The nervous system is made up ofØ nervous tissues)
·
What
are the functions of sensory neurons and motor neurons?Ø
(Sensory neurons transmit messages or nerve impulses from the sense
organs to the brain or spinal cord and motor neurons transmit messages or nerve
impulses from the brain and spinal cord to organs, muscles or glands.)
·
Which
part of the nervous system increases the activity of an organ to meetØ requirements of the body?
(sympathetic autonomic nervous system)
·
Which
part of the peripheral nervous system is responsible for coordinatingØ
body movements and receiving external stimuli from the sense organs and
muscles?
(somatic nervous system)
·
Which
part of the brain controls involuntary actions reflex actions such asØ sneezing, coughing and vomiting?
(medulla oblongata) If you touch a
hot object, you immediately remove your hand. Which senseØ organ helps you to feel the temperature of an object?
(skin)
Wednesday, 20 January 2016
The Teen Years
The Teen Years
Ø What is meant by
adolescence?
(adolescence is the period of life when the body undergoes changes leading
to reproductive maturity)
Ø Give examples of any
three secondary sexual characters that are seen in
human males.
(the secondary sexual characters seen in human males are development of
facial hair such as beard and moustache, development of hair on the chest,
in armpits and the pubic region, increased size of the larynx seen as the
Adam’s apple)
Ø Give examples of any
two secondary sexual characters that are seen in
human females.
(the secondary sexual characters
seen in human females are development of breasts and broadening of the hip
region, growth of hair in the armpits and pubic region)
Ø What is menopause?
(in females, the menstrual cycle
comes to an end around the age of 45 -50 years and this phase is called
menopause)
Ø What is endometrium?
(the endometrium is the inner layer or inner lining of the uterus)
Ø What may happen to the
endometrium in the absence of progesterone?
(In the absence of progesterone, the endometrium remains thin and
inactive).
Family
X
Father+ mother
daughter
daughter
daughter
ØWhat do you observe?
(the
given family has 3 daughters and no son)
Ø Which type of chromosomes determinescharacteristics of the
individual,
Such as height,colour of eyes etc.?
(autosomes)
ØWhich type of chromosomes determines gender of a child?
(sex chromosomes)
ØHow is zygote formed?
(The zygote is formed by the fusion
of the egg cell from the mother and the sperm cell from the father)
ØWhat will happen if the sperm taking part in fertilization carries
X chromosome?
(the zygote will develop into a female child)
ØIt is necessary to provide the body with good nutrition,
proper exercise and
adequate rest during the period of adolescence.Why?
Adolescence is the age of rapid physical
and mental growth leading to development
;therefore it is necessary to provide
the body with good nutrition, proper exercise and adequate rest during the period
of adolescence.
Monday, 18 January 2016
Monday, 11 January 2016
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