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.,

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)