Science Activity for Class VIII - Cbse

97 Pages·2001·1.86 MB·English

CLASS
viii
Learning by Doing
Science Activity Book
CENTRAL BOARD OF SECONDARY EDUCATION
PREET VIHAR, DELHI - 110092
Learning by Doing, Science Activity Book for Class 8th
PRICE : Rs. 50.00
FIRST EDITION 2009 © CBSE, India
COPIES : 25,000
PUBLISHED BY : The Secretary, Central Board of Secondary Education, Shiksha Kendra,
2, Community Centre, Preet Vihar, Delhi - 110092
DESIGN, LAYOUT & : Multi Graphics, 5745/81, Reghar Pura, Karol Bagh, New Delhi - 110092.
ILLUSTRATIONS BY Phone : [phone]
PRINTED BY : Vijayalakshmi Printing Works (P) Limited
B-117, Sector-5, Noida,-201301, Ph.: 0120-2421763, 2421977
FFoorreewwoorrdd
Science is being taught is school in a very mechanical way. Students are confined to their textbooks, the
topics and contents included therein. They are hardly encouraged to observe, explore, look for
patterns or analyse the everyday experience occurring around them. Mere rote memorization of
concepts is leading children towards a stressful existence. NCF 2005 aptly says, "The fact that learning
has become a source of burden and stress on children and their parents is an evidence of a deep
distortion in educational aims and quality". To correct this, the NCF has proposed five guiding
principles. Some of these are;
i) connecting knowledge to life outside school
ii) ensuring that learning shifts away from rote methods.
The present document "Learning by doing" is an effort by the Board to make Science learing more
meaningful, interesting and joyful. This document is in continuity to our earlier documents for classes
VI and VII brought out in preceding years. An effort has been made to include activities which are based
on different content areas and concepts given in NCERT textbook in Science for class VIII. It is hoped
that after performing these activities, students will be able to understand the concepts better,
internalize them and will be motivated to create more such experiences. Wide variety of activities
including observation, exploration, analysis, games, riddles, crossword puzzles etc. have been included
to meet diverse needs of learners and help them appreciate and enjoy the learning experiences. The
suggested activities have been so designed that they can be done easily without using expensive
materials or equipment.
I take this opportunity to put on record my sincere and heartfelt thanks to all the members of the
development and editorial team for sparing their valuable time and extending their expertise in
finalization of this document. My deep appreciation and thanks are due to Smt. C. Gurumurthy,
Director (Acad.), CBSE for providing guidelines and directions at different stages of preparation of this
document. Dr. (Mrs.) Srijata Das, Education Officer, CBSE deserves special mention and appreciation
for putting in her honest efforts in perceiving, coordinating and completing the documents in time.
It is hoped that all the schools and Science teachers would use this document in right spirit and
encourage the students to perform these activities and learn by doing rather than rote memorization.
In its endeavour for continuous improvement the Board welcomes observations, comments and
suggestions from the users.
Vineet Joshi
Chairman
i
AAcckknnoowwlleeddggeemmeennttss
CBSE Advisors:
Sh. Vineet Joshi Chairman
Smt. C. Gurumurthy Director Academic
Material Developmental Team:
Dr. V.P. Singh State Project Director, UEE Mission
Mrs. VidhuNarayanan Teacher, Sardar Patel Vidyalaya, Lodhi Estate, New Delhi
Mrs. K. Syamala Teacher, Sardar Patel Vidyalaya, Lodhi Estate, New Delhi
Mrs. Shivani Goswami 1-1756, CR Park, New Delhi
Mrs. Soma Singh Teacher, Delhi Public School, Ghaziabad
Mrs. Neelam Batra Teacher, D.C. Arya Sr. Secondary School, Lodhi Road,
New Delhi
Editorial Team
Sh. S.K. Munjal Principal, St. Margaret School, Rohini, Delhi
Sh. C.B. Verma Retd. Principal, D.C. Arya Sr. Secondary School, Lodhi
Road, New Delhi
Dr. Subhasri Sinha Sr. Lecturer, SCERT, Defence Colony, New Delhi
Mrs. Vidhu Narayanan Teacher, Sardar Patel Vidyalaya, Lodhi Estate, New Delhi
Mrs. Sangeeta Teacher, St. Margaret School, Rohini, Delhi

Member Coordinator:
Dr. Srijata Das Education Officer, CBSE, Delhi
ii
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iii
THE CONSTITUTION OF INDIA
PREAMBLE
WE, THE PEOPLE OF INDIA, having solemnly resolved to constitute India into a 1 SOVEREIGN
SOCIALIST SECULAR DEMOCRATIC REPUBLIC and to secure to all its citizens :
JUSTICE, social, economic and political;
LIBERTY of thought, expression, belief, faith and worship;
EQUALITY of status and of opportunity; and to promote among them all
FRATERNITY assuring the dignity of the individual and the 2 [unity and integrity of the Nation];
IN OUR CONSTITUENT ASSEMBLY this twenty-sixth day of November, 1949, do HEREBY TO
OURSELVES THIS CONSTITUTION.
1. Subs, by the Constitution (Forty-Second Amendment) Act. 1976, sec. 2, for "Sovereign Democratic Republic (w.e.f. 3.1.1977)
2. Subs, by the Constitution (Forty-Second Amendment) Act. 1976, sec. 2, for "unity of the Nation (w.e.f. 3.1.1977)
THE CONSTITUTION OF INDIA
Chapter IV A
Fundamental Duties
ARTICLE 51A
Fundamental Duties - It shall be the duty of every citizen of India-
(a) to abide by the Constitution and respect its ideals and institutions, the National Flag and the National
Anthem;
(b) to cherish and follow the noble ideals which inspired our national struggle for freedom;
(c) to uphold and protect the sovereignty, unity and integrity of India;
(d) to defend the country and render national service when called upon to do so;
(e) To promote harmony and the spirit of common brotherhood amongst all the people of India
transcending religious, linguistic and regional or sectional diversities; to renounce practices
derogatory to the dignity of women;
(f) to value and preserve the rich heritage of our composite culture;
(g) to protect and improve the natural environment including forests, lakes, rivers, wild life and to have
compassion for living creatures;
(h) to develop the scientific temper, humanism and the spirit of inquiry and reform;
(i) to safeguard public property and to abjure violence;
(j) to strive towards excellence in all spheres of individual and collective activity so that the nation
constantly rises to higher levels of endeavour and achievement.
iv
CCoonntteennttss
ACTIVITIES PAGE NO. ACTIVITIES PAGE NO.
Forward MATERIALS - METALS AND NON- METALS 43
LIGHTER OR HEAVIER?
Introduction
CHEMICAL EFFECTS OF CURRENT 45
FORCE AND PRESSURE 1
WHAT MAKES WATER?
LIGHT 3
COMBUSTION AND FLAME 47
MAKE YOUR LITTLE MOVIE
A Surprising Fact
LIGHT 6
SYNTHETIC FIBRES AND PLASTICS 49
MAKE A PERISCOPE
INTERVIEW FOR MAKING MERIT LIST
SOUND 9
POSTER MAKING 52
SUNO! SUNO!
SYNTHETIC FIBRES AND PLASTICS
SOUND 11
CROP PRODUCTION AND MANAGEMENT 54
LET'S MAKE MUSIC
PITCHER POWER
SOUND 15
CROP PRODUCTION AND MANAGEMENT 56
I CAN SEE MY SOUND!
JUST FOR FUN
SOUND 17
CROP PRODUCTION AND MANAGEMENT 58
HOW DOES SOUND TRAVEL?
BACK TO THE EARTH
STARS AND THE SOLAR SYSTEM 19
MICRO ORGANISMS : FRIEND AND FOE 60
IS THE MOON GROWING OR SHRINKING ?
A MOULDY PARTY
STARS AND THE SOLAR SYSTEM 22
MICRO ORGANISMS : FRIEND AND FOE 63
MAKING A SOLAR SYSTEM MOBILE
SPORE MAGIC
LIGHT 24
MICRO ORGANISMS : FRIEND AND FOE 65
I CAN SEE IT, I CANNOT !
A FRIEND INDEED
FORCE AND PRESSURE 26
CONSERVATION OF PLANTS & ANIMALS 68
EGG POPS INTO A BOTTLE
A TREE STUDY
FORCE AND PRESSURE 28
CONSERVATION OF PLANTS & ANIMALS 70
A FORCEFUL STORY
WINDOW TO OUR RICH BIODIVERSITY
SOME NATURAL PHENOMENA 30
CELL-STRUCTURE & FUNCTIONS 75
WANT TO BE A SNAKE CHARMER?
INSIDE STORY
FRICTION 32
REPRODUCTION IN ANIMALS 77
THE BALL BEARING
STORY OF GRANNY AND HER CHILDREN
FRICTION
REPRODUCTION IN ANIMALS 79
THE TUG OF WAR 35
STAGES OF HUMAN REPRODUCTION
SOME NATURAL PHENOMENA
REACHING THE AGE OF ADOLESCENCE 82
MYSTERIOUS FORCES 37
PLEASE HEAR WHAT I AM NOT SAYING
COAL AND PETROLEUM 39
REACHING THE AGE OF ADOLESCENCE 84
ITS CO AGAIN
2 DELIGHTFUL DAYDREAMS
COAL AND PETROLEUM 41
REACHING THE AGE OF ADOLESCENCE 86
THE PUZZLING LETTERS
GROWING UP
MATERIALS - METALS AND NON- METALS 42
BRING BACK THE SHINE
v
IInnttrroodduuccttiioonn
Science is a dynamic, expanding body of knowledge. It involves observing, exploring,
hypothising, verifying, analyzing and interpreting various phenomena occurring around us.
It is common knowledge that except few, hardly does any Science teacher encourages a
student to go beyond the content and concepts given in the textbook. This is making the
subject boring and dull.
Science can be made lively and interesting by giving students hands on experiences and by
encouraging them to ask questions, observe, explore, experiment and investigate. Learning
should not remain confined to the classroom alone but it should be intricately woven into
the experience of the daily lives of the students. This document "Learning by Doing" for
class VIII is aimed at meeting some of these aspirations and expectations of the subject.
The activities included in this document are based on the content/concepts given in NCERT
textbook in Science for class VIII. Effort has been made to keep the activities very simple
easy to perform with minimum cost involvement. The activities are of different types
involving observation, exploration, experimentation, investigation. Some of the activities
are in the form of riddles, games and puzzles.
It is hoped that students and teachers will use this book in the right spirit and pave the way
for better teaching-learning process in Science.
Dr. Srijata Das
Education Officer, CBSE, Delhi
vi
1
&
FORCE
PRESSURE
THE STORY OF
MAGDEBERG HEMISPHERE
Long Time ago there was a man called Otto von Guerick who lived in the town of Magdeberg in Germany.
One day he invited everyone in the town to come and watch a spectacular event. All the people who came
to watch were very impressed with what he had done. Do you want to know what happened? He took two
large copper hemispheres that fitted together. He pumped out air from in between these two
hemispheres. He then tied sixteen horses, eight on each side of the hemispheres. But what was so
spectacular about this? However hard they were made to pull, the horses were unable to pull the
hemisphere apart! But as soon as Mr. Guerick allowed air into the sphere again, the hemispheres
separated. Isn't that wonderful?
Many of you must be wishing that if only you had horses, rope and copper hemispheres to try it out again.
Well! You don't need all these. You can repeat the Magdeberg experiment with very simple things too!
You will need: Two tins of the same size, filter paper, scissors, water, strips of paper and matchbox.
What to do:
• Take two tins of the same size.
• Estimate the diameter of the mouth of
the tin.
• Cut out a circle from the filter paper that
has a diameter slightly larger than the
diameter of the mouth of the tins.
• Draw a circle of radius about 2cm less
than the radius of the circle cut out
earlier.
• Cut along the inner circle so as to make a
hole. (fig.1)
• Wet this filter paper circle by just
dipping it in water. Now place it on top of
one of the tins. (fig.2)
• Burn a few strips of paper and drop them
in the same tin.
• Quickly place the second tin on the first
so that the mouths of the two tins are
one above the other and the circular
sheet of paper is in between the two
tins. (fig.3)
• Now pick up the upper tin. What do you
find? Does the lower tin also follow the
upper one? Do they seem glued together?
Fig. 1
1