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Basic Guidelines for
Excellence in Laboratory practices
in
SCIENCE(Class IX & X)
For
Laboratory Assistants2013
Chief Advisor
Ms. Anita Satia,Director, SCERT
Guidance
Dr. Pratibha SharmaJt. Director, SCERT
Advisors
Mr. Ashok AnandVice Principal, (Retd.) D.O.E.
Mr. Ravinder SharmaPrincipal, SCSD Sarvdaya Vidyalaya, Sec. 9, Rohini
Contribution
Mr. Johnson David Mr. Lalit GuptaLecturer (Biology) (Retd.) D.O.E Lecturer (Chemistry) GBSSS Bindapur, Delhi
Mr. Yogesh Mudgal Mr. V.S. MalikLecturer (physics) SCSD Lecturer (Biology) RPVV, Civil Lines,
Sarvodaya Vidyalaya sec-9, Rohini Delhi-54
Mr. Naveen Malik, Ms. Neelam Batra, Lecturer (Chemistry) SCSD Lecturer (Physics) D.C. Arya S.S.S. Lodhi
Sarvodaya Vidyalaya sec-9, Rohini Colony, Delhi
Ms. Harpreet Kaur Ms. BhavnaTGT, (N.Sc) GGSSS No.2 Lecturer (Physics) G. Co-Ed Sarvodaya
Uttam Nagar Vidyalaya Sec-8, Rohini
Publication Incharge
Ms. Sapna YadavMs. Meenakshi Yadav
Publication Team
Mr. Navin Kumar Ms. Radha Mr. Jai Bhagwan
Printed by : CHAUHAN ART PRESS150, D.B. Gupta Mkt., Karol Bagh, New Delhi-5 Tel : 9711811511
Advisors & Editor
Dr. S.V. MalikLecturer, SCERT
ACKNOWLEDGMENT
It is a matter of immense pleasure that a “laboratory manual for laboratory
assistants” has emerged as a document, sincere gratitude and thanks are extended
toward all those who were involved in the different stages of development of the
manual. I acknowledge the efforts of Dr. S. V. Malik, Co-ordinator of this endeavour, and
the members of the team who made their valuable contribution. I am grateful to Mr.
Ravinder Sharma, Principal, for his able guidance in the subject matter, administrative
support, and in providing space and serene atmosphere to bring the manual in a
presentable shape. I am also grateful to the participating teachers and subject experts
for presenting their critical, professional and thoughtful views during the refinement
process of the manual. Highly indebted for the Delhi State Science Teachers' Forum
Delhi for providing resource persons for this task.
Comments and suggestion from our readers/users for further improvement of
the manual are warmly welcome.
DirectorSCERT
CONTENTS
1. Introduction
2. Changes in Syllabus of Sec. Classes (2013 & 2014) 1
3. List of Experiments (as per CBSE Sec. School Curriculum 2013 & 2014)
4. Science Practicals Class IX 1st Term
5. Science Practicals Class IX 2nd Term
6. Science Practicals Class X 1st Term
7. Science Practicals Class X 2nd Term
8. Components of a Good laboratory
9. List of Equipments used in Laboratory
10. List of Chemicals
11. Preparation of Some reagents used in laboratory
12. Stock maintenance and Condemnation procedures
13. Life of articles
14. First aid kit in laboratory
15. Fire Safety (Aag Se Suraksha)
16. Duties of Laboratory Assistant
17. Guidelines for Lab. Assistant
18. Important circulars of CBSE
19. References
INTRODUCTION
Science is a subject which is best learnt by performing hands on experiments.
The Science laboratory at the school facilitates this experience. It is a place where the
students test their theoretical knowledge practically for its validity or truthfulness.
A science student cannot learn without a laboratory where he/she gains practical
hands –on experience.
The experiments prescribed by CBSE at the secondary level (Class IX and
Class X) are meant to develop basic skills of measurement, handling of some common
measuring devices; equipment and chemicals; setting simple apparatus; preparing
slides; making observations, collecting data, presenting them in appropriate format and
preparing report.
A laboratory is a very significant place where necessary science equipment,
chemicals and required facilities are available. Here the role of Laboratory Assistant
becomes pivotal. He is the person who acts as a guide and a patron and also the
caretaker of young and tender minds. Many of these students chart a path of scientific
discoveries of our future.
A Lab assistant being the soul of the laboratory should have due knowledge of all
the procedures practiced in the lab. An important part of these procedures is
identification of proper equipment, thorough knowledge with respect to the
experiments to be performed in lab. In this respect this manual has been prepared
keeping in mind the requisites of the lab assistant. In this manual the experiments have
been illustrated according to CBSE secondary school curriculum 2013, 2014. A sincere
attempt has been made to equip lab assistants with respect to performing all the
experiments. Thus lab assistants will find themselves updated with latest experiments
and this in turn would help in the effective management and control of lab activities.
The lab assistants need to work in tandem with Science teachers. They must not
hesitate and consult the Science teacher in case they have difficulty in handling the
equipment or chemicals. It is very important that they must cooperate and coordinate
with teachers and students. It is also expected that the lab assistant is able to quickly
identify and arrange for all materials required for conduct of experiment.
A number of suggestions have been incorporated in this manual. All valuable
suggestions for improvement of science practical skills, critical ideas and innovative
approaches for betterment of science education will be highly appreciated.
Dr. S. V. Malik, Nodal officerLab Assistant Training Programme
NOTE FOR THE USER
The National Curriculum Framework-2005 encourage the experimental work
and introduction of carefully designed experiments, because performing experiments
with own hands is a thrilling experience that facilities “Learning by doing”. In
consonance with this spirit, SCERT has produced laboratory manuals/modules to cater
the need of the students, teachers and laboratory assistants.
In the upkeep and soothing functioning of the laboratory, a laboratory assistant
has a pivotal role to play. In the contemporary situation of practical work in the school
milieu, particularly in the formative stage of learning in science, i.e. the secondary stage
(class IX and X), the need is felt for laboratory assistant to provide them guidance in
setting up of laboratory, making familiar with activities/experiments, handling of
experiments/materials with utmost care and sophistication. Taking account of these
exigencies, SCERT had developed laboratory manual in 2009 and its supplementary in
2010, by taking sole consideration of laboratory assistants. Inservice training
programme of three week duration was imparted. Moving on with time, a need for more
updated manual has arisen because CBSE made certain changes in the gamut of
prescribed practicals in the syllabus, which included both the addition, deletion and
relocation. These changes are to be effective from 2013 onwards, so we need to be
updated and prepared.
The manual is useful for the student and teacher in general and laboratory
assistant in particular (both for serving and new entrants in the stream). It is designed in
keeping the consideration of being familiar with material/equipment/apparatus/
reagents; hands on experience, brush up with practical work; maintenance of stock and
condemnation procedures; hazards in the laboratory and remedial measures etc.,
Knowledge of the basic duties and responsibilities will enable him to be a soul of the
laboratory. This is the shining aspect of the manual.
Hope for the manual’s success in fulfillment of its aim and objectives.
Dr. S.V. Malik
Nodal Officer
Changes in CBSE Secondary SchoolScience Practicals in 2012,2013,2014
1
2
CBSE SECONDARY SCHOOLCURRICULUM 2013
CLASS IX
PRACTICALS FOR SUMMATIVE ASSESSMENT I :
1. To test (a) the presence of starch in the given food sample (b) the presence of the adulterant metanil yellow in dal.
2. To prepare
a) A true solution of common salt, sugar and alum
b) A suspension of soil, chalk powder and fine sand in water
c) A colloidal of starch in water and egg albumin in water and distinguish between these on the basis of
- transparency
- filtration criterion
- stability
3. To prepare
a) a mixture
b) a compound
using iron filings and sulphur powder and distinguish between these on the basis of:
i. appearance i.e., homogeneity and heterogeneity
ii. behaviour towards a magnet
iii. behaviour towards carbon disulphide as a solvent.
iv. effect of heat.
4. To carry out the following reactions and classify them as physical or chemical changes.
a. Iron with copper sulphate solution in water.
b. Burning of magnesium in air.
c. Zinc with dilute sulphuric acid
d. Heating of copper sulphate
e. Sodium sulphate with barium chloride in the form of their solutions in water.
5. To prepare stained temporary mounts of (a) onion peel and (b) human cheek cells and to record observations and draw their labeled diagrams.
6. To identify parenchyma and sclerenchyma tissues in plants, striped muscle fibers and nerve
3
cells in animals,from prepared slides and to draw their labeled diagrams.
7. To separate the components of a mixture of sand, common salt and ammonium chloride (or camphor) by sublimation.
8. To determine the melting point of ice and the boiling point of water.
9. To study the third law of motion using two spring balances.
10. To determine the mass percentage of water imbibed by raisins.
PRACTICALS FOR SUMMATIVE ASSESSMENT II :
1. To verify laws of reflection of sound.
2. To determine the density of solid (denser than water) by using a spring balance and a measuring
cylinder.
3. To establish the relation between the loss in weight of a solid when fully immersed in
a. tap water
b. strongly salty water, with the weight of water displaced by it by taking at least two different solids.
4. To observe and compare the pressure exerted by a solid iron cuboid on fine sand/ wheat flour while
resting on its three different faces and to calculate the pressure exerted in the three different cases.
5. To determine the velocity of a pulse propagated through a stretched string/slinky.
6. To study the characteristic of spirogyra/Agaricus, Moss/Fern, Pinus ( either with male or female cone)
and an Angiospermic plant. Draw and give two identifying features of groups they belong to.
7. To observe and draw the given specimens-earthworm, cockroach, bony fish and bird. For each
specimen record
a. one specific feature of its phylum.
b. one adaptive feature with reference to its habitat.
8. To verify the law of conservation of mass in a chemical reaction.
9. To study the external features of root, stem, leaf and flower of monocot and dicot plants.
10. To study the life cycle of mosquito .
CLASS X
PRACTICALS FOR SUMMATIVE ASSESSMENT I :
1. To find the pH of the following samples by using pH paper/universal indicator.
a. Dilute Hydrochloric acid
b. Dilute NaOH solution
c. Dilute ethanoic acid solution
4
d . Lemon juice
e. Water
f. Dilute sodium bicarbonate solution.
2. To study the properties of acids and bases HCl & NaOH by their reaction with
a. Litmus solution (Blue/Red)
b. Zinc metal
c. Solid sodium carbonate
3. To perform and observe the following reactions and classify them into:
i. Combination reaction
ii. Decomposition reaction
iii. Displacement reaction
iv. Double displacement reaction
1) Action of water on quick lime.
2) Action of heat on ferrous sulphate crystals.
3) Iron nails kept in copper sulphate solution.
4) Reaction between sodium sulphate and barium chloride solutions.
4. a) To observe the action of Zn, Fe, Cu and Al metals on the following salt solutions.
a. ZnSO (aq)4
b. FeSO (aq)4
c. CuSO (aq)4
d. Al2 (SO )3(aq)4
b) Arrange Zn, Fe, Cu and Al metals in the decreasing order of reactivity based on the above result.
5. To study the dependence of potential difference (V) across a resistor on the current (I) passing through it and determine its resistance. Also plot a graph between V and I.
6. To determine the equivalent resistance of two resistors when connected in series.
7 To determine the equivalent resistance of two resistors when connected in parallel.
8 To prepare a temporary mount of a leaf peel to show stomata.
9 To show experimentally that light is necessary for photosynthesis.
10 To show experimentally that carbon dioxide is given out during respiration
PRACTICALS FOR SUMMATIVE ASSESSMENT II :
1. To study the following properties of acetic acid (ethanoic acid) :
5
I) odour
ii) solubility in water
iii) effect on litmus
iv) reaction with sodium bicarbonate
2. To study saponification reaction for preparation of soap.
3. To study the comparative cleaning capacity of a sample of soap in soft and hard water.
4. To determine the focal length of
i. Concave mirror
ii. Convex lens
by obtaining the image of a distant object.
5. To trace the path of a ray of light passing through a rectangular glass slab for different angles of incidence.
Measure the angle of incidence, angle of refraction, angle of emergence and interpret the result.
6. To study (a) binary fission in Amoeba and (b) budding in yeast with the help of prepared slides.
7. To trace the path of the rays of light through a glass prism.
8. To find the image distance for varying object distances in case of a convex lens and draw corresponding ray diagrams to show the nature of image formed.
9. To study homology and analogy with the help of preserved / available specimens of either animals or plants.
10. To identify the different parts of an embryo of a dicot seed ( Pea, gram or red kidney bean).
6
CBSE SECONDARY SCHOOLCURRICULUM 2014
CLASS IX
PRACTICALS FOR SUMMATIVE ASSESSMENT I :
1. To test (a) the presence of starch in the given food sample (b) the presence of the adulterant metanil yellow in dal.
2. To prepare
a) a true solution of common salt, sugar and alum
b) a suspension of soil, chalk powder and fine sand in water
c) a colloidal of starch in water and egg albumin in water and distinguish between these on the basis of
- transparency
- filtration criterion
- stability
3. To prepare
a) a mixture
b) a compound
using iron filings and sulphur powder and distinguish between these on the basis of:
i. appearance i.e., homogeneity and heterogeneity
ii. behaviour towards a magnet
iii. behaviour towards carbon disulphide as a solvent.
iv. effect of heat.
4. To carry out the following reactions and classify them as physical or chemical changes.
a. Iron with copper sulphate solution in water.
b. Burning of magnesium in air.
c. Zinc with dilute sulphuric acid
d. Heating of copper sulphate
e. Sodium sulphate with barium chloride in the form of their solutions in water.
5. To prepare stained temporary mounts of (a) onion peel and (b) human cheek cells and to record observations and draw their labeled diagrams.
6. To identify parenchyma and sclerenchyma tissues in plants, striped muscle fibers and nerve cells in animals,from prepared slides and to draw their labeled diagrams.
7. To separate the components of a mixture of sand, common salt and ammonium chloride (or camphor) by sublimation.
7
8. To determine the melting point of ice and the boiling point of water.
9. To establish relationship between weight of a rectangular wooden block lying on a horizontal table and the minimum force required to just move it using a spring balance.
10. To determine the mass percentage of water imbibed by raisins.
PRACTICALS FOR SUMMATIVE ASSESSMENT II :
1. To verify laws of reflection of sound.
2. To determine the density of solid (denser than water) by using a spring balance and a measuring cylinder.
3. To establish the relation between the loss in weight of a solid when fully immersed in
a. tap water
b. strongly salty water, with the weight of water displaced by it by taking at least two different solids.
4. To observe and compare the pressure exerted by a solid iron cuboid on fine sand/ wheat flour while resting on its three different faces and to calculate the pressure exerted in the three different cases.
5. To determine the velocity of a pulse propagated through a stretched string/slinky.
6. To study the characteristic of spirogyra/Agaricus, Moss/Fern, Pinus ( either with male or female cone) and an Angiospermic plant. Draw and give two identifying features of groups they belong to.
7. To observe and draw the given specimens-earthworm, cockroach, bony fish and bird. For each specimen record
a. one specific feature of its phylum.
b. one adaptive feature with reference to its habitat.
8. To verify the law of conservation of mass in a chemical reaction.
9. To study the external features of root, stem, leaf and flower of monocot and dicot plants.
10. To study the life cycle of mosquito.
CLASS X : - 2014
PRACTICALS FOR SUMMATIVE ASSESSMENT I:
1. To find the pH of the following samples by using pH paper/universal indicator.
a. Dilute Hydrochloric acid
b. Dilute NaOH solution
c. Dilute ethanoic acid solution
d. Lemon juice
e. Water
f. Dilute sodium bicarbonate solution.
8
2. To study the properties of acids and bases HCl & NaOH by their reaction with
a. Litmus solution (Blue/Red)
b. Zinc metal
c. Solid sodium carbonate
3. To perform and observe the following reactions and classify them into:
i. Combination reaction
ii. Decomposition reaction
iii. Displacement reaction
iv. Double displacement reaction
1) Action of water on quick lime.
2) Action of heat on ferrous sulphate crystals.
3) Iron nails kept in copper sulphate solution.
4) Reaction between sodium sulphate and barium chloride solutions.
4. a) To observe the action of Zn, Fe, Cu and Al metals on the following salt solutions.
a. ZnSO (aq)4
b. FeSO (aq)4
c. CuSO (aq)4
d. Al2 (SO )3(aq)4
b) Arrange Zn, Fe, Cu and Al metals in the decreasing order of reactivity based on the above result.
5. To study the dependence of potential difference (V) across a resistor on the current (I) passing through it and determine its resistance. Also plot a graph between V and I.
6. To determine the equivalent resistance of two resistors when connected in series.
7. To determine the equivalent resistance of two resistors when connected in parallel.
8. To prepare a temporary mount of a leaf peel to show stomata.
9. To show experimentally that light is necessary for photosynthesis.
10. To show experimentally that carbon dioxide is given out during respiration
PRACTICALS FOR SUMMATIVE ASSESSMENT II :
1. To study the following properties of acetic acid (ethanoic acid) :
I) odour
ii) solubility in water
iii) effect on litmus
iv) reaction with sodium bicarbonate
2. To study saponification reaction for preparation of soap.
9
3. To study the comparative cleaning capacity of a sample of soap in soft and hard water.
4. To determine the focal length of
i. Concave mirror
ii. Convex lens
by obtaining the image of a distant object.
5. To trace the path of a ray of light passing through a rectangular glass slab for different angles of incidence.
Measure the angle of incidence, angle of refraction, angle of emergence and interpret the result.
6. To study (a) binary fission in Amoeba and (b) budding in yeast with the help of prepared slides.
7. To trace the path of the rays of light through a glass prism.
8. To find the image distance for varying object distances in case of a convex lens and draw corresponding ray diagrams to show the nature of image formed.
9. To study homology and analogy with the help of preserved / available specimens of either animals or plants.
10. To identify the different parts of an embryo of a dicot seed ( Pea, gram or red kidney bean).
10
CLASS IX
EXPERIMENT NO: 1
AIM: To test (a) the presence of starch in the given food sample (b) the presence of the adulterant metanil yellow in dal.
MATERIAL REQUIRED : Potato, Pigeon pea, iodine solution, petridish, conc.HCl, test tubes, test tube holder, and test tube stand.
PROCEDURE:
TO TEST THE PRESENCE OF STARCH:
1. Take the food material to be tested in a test tube.
2. Take boiled rice or bread. Prepare a paste or suspension of these materials.
3. In case of potato cut it into very small pieces. Put it in the test tube.
4. Now add a few drops of iodine solution to the test tubes.
5. Observe the change in color if any.
OBSERVATION:
S.no Food Material Change in color
1 Boiled rice Blue black color
2 Potato Blue black color
3 Bread Blue black color
Iodinesolution
Food Material
11
TO TEST THE PRESENCE OF METANIL YELLOW IN PIGEON PEA:
1. Take 5 gm of pigeon pea sample in a dry test tube.
2. Add 10 ml. of distilled water to this and shake well.
3. Separate the filtrate in a test tube.
4. To 1 ml of this filtrate adds 2-3 drops of conc. Hydrochloric acid.
5. Now note the change in color of reaction mixture.
OBSERVATION:
On adding the conc.HCl a pink or magenta coloration appears which persists even after dilution.
INFERENCE:
On the basis of above observations
A. If the color in test tubes changes to blue black on addition of Iodine we can easily say that starch is present in the given food material.
B. On treating Pigeon pea filtrate with conc.HCl the color change to pink or magenta shows presence of adulterants.
PRECAUTIONS:
1. Always use clean and dry glassware.
2. The chemicals should be handled with care.
3. Always rinse and use a fresh dropper to add the reagents to the test tube.
4. Verify the colour test against a white background for accurate colour.
12
CLASS IX
EXPERIMENT No: 2
AIM:
(a) True solution of NaCl in water
(b) Colloid of starch in water
(C) Suspension of chalk powder in water
Materials Required : Beaker (250 ml), glass rod, measuring cylinder, common salt, water, starch powder and black board chalk.
(a) True solution :-
Procedure :
1. Take 100 ml of water in a measuring cylinder and transfer it to a clean 250 ml beaker.
2. Add about 1 spoon of NaCl to it.
3. Stir it with the help of a glass rod a clear solution is formed.
Note : (If any insoluble impurity is there then filter it and take the clear filterate.)
4. The resulting solution is a true solution.
Precaution :
1. Common salt should be taken in powdered form.
2. Beaker and glass rod should be cleaned before the experiment.
3. Stirring should be done in such a way that glass rod does not strike against the sides of the beaker.
(b) Suspension :-
Procedure :
1. Convert half piece of black board chalk into powdered form.
2. Take 100 ml water in a measuring cylinder and transfer it to a 250 ml beaker.
3. Add powdered chalk to water.
4. Stir vigorously for 5 minutes.
5. The resulting mixture is suspension of chalk in water.
13
Precaution :
1. Chalk should be used in powdered form.
2. Beaker and glass rod should be cleaned before the experiment.
3. Stirring should be done in such a way that glass rod does not strike against the sides of the beaker.
C. Colloid :-
Procedure :
1. Take 5 g starch in a 250 ml beaker.
2. Add a few drops of water to it and mix with a glass rod to make paste.
3. Add 100 ml of water to it with the help of measuring cylinder.
4. Heat gently with constant stirring till mixture appears without any visible suspended particle.
5. The resulting mixture is colloid of starch in water.
Precautions :
1. Starch should be taken in the form of fine powder.
2. Beaker and glass rod should be cleaned before the experiment.
3. Stirring should be done in such a way that glass rod does not strike against the sides of the beaker.
4. Heating of beaker should be done on wire gauge only.
14
CLASS IX
EXPERIMENT No: 3
AIM: To prepare (a) mixture (b) compound using iron fillings & sulphur and to differentiate between them.
Materials Required : Iron filling, Sulphur powder, Dil. Sulphuric acid, china dish, Test tube, burner, magnet & Carbon disulphide.
Procedure :
(a) Mixture : Take 7 iron fillings & 4g sulphur powder. Grind them with the help of Pestle & mortar. Label it as “MIXTURE” ‘A’
(b) Compound : Take 7g iron filling & 4g sulphur powder in a china dish.
Heat it gently till a black mass is formed.
Label it as “Compound” ‘B’
Difference between “Mixture” and “Compound”
Experiment Observation Inference
1 Magnet Test Move a magnet sample ‘A’ the Properties of substance are
Over the sample (a) In mixture iron of retained hence ‘A’ is a
fillings are attracted mixture’“
Sample ‘B’ Properties Of substance
In compound no not retained hence ‘B’ is a
attraction takes place. Compound.
2 Carbon disulphide Shake both In ‘A’ mixture sulphur Properties of sulphur are
Test Samples with gets Dissolved. retained In ’A’ mixture but
Carbon disulphide not in compound ‘B’
In ‘B’ compound no Hence ‘A’ is a mixture and
change... ‘B’ is a compound.
3 Dil. Sulphuric React both the Mixture ‘A’ gives Properties of iron are
Acid Test samples with Dil. Hydrogen gas which retained in mixture ‘A’ but
Sulphuric Acid. burns with a pop sound not in compound ‘B’.
when burning match
stick is brought.
15
Over it ‘B. Compound Hence the substance ‘A’ is a
gives Hydrogen mixture and ‘B’ is a
Sulphide gas compounds
Having a rotten egg
like smell.
Inference :
1. Properties of components are retained in mixture.
2. Properties of a components are retained in mixture.
Precaution :
1. Heating of iron & sulphur shold be done gently.
2. Do not inhale hydrogen sulphide gas.
3. Carbon disulphide should be kept a way from flame.
16
CLASS IX
EXPERIMENT No: 4
AIM: To carry out the following reactions and classify them as physical or chemical changes.
(a) Iron with copper sulphate solution
(b) Buring of magnesium in ribbon in air
(c) Zinc with dil. Sulphuric acid
(d) Heating of lead nitrate
(e) Sodium sulphate solution with barium chloride solution.
Materials Required : Copper sulphate solution, iron nails, Test tubes, Thread, Beaker and test tube stand.
Part (a) Procedure : Take copper sulphate solution in a test tube Dip two iron nails into it.
Observation : Brown coating of copper metal is seen on iron nails after 15 minutes.
Inference : Copper is displaced by iron.
Inference :
1. Iron is more reactive than copper.
2. This is a displacement reaction.
Precautions :
1. Iron nail should be free form dust or rust.
2. About 15 minutes time should be taken before taking observation.
Part (b) Material Required : Magnesium ribbon, A pair of tongs, Match box, china dish and burner.
Observation : A sparkling light is seen and when product formed is allowed to fall a china dish a white powder is seen.
Inference : Magnesium oxide is formed.
Inference :
1. Magnesium burns in air to form magnesium oxide.
2. This reactions is a combination reaction.
17
Precautions :
1. Magnesium ribbon should be cleaned with a sand paper before burning.
2. Magnesium ribbon should be taken into flame with the help of a pair of tongs only.
3. Sparkling light produced should be seen not for a long time.
Part (c) Materials Required : Zinc granules, Dil. Sulphuric acid, test tube, test tube stand, match box.
Procedure :
1. Put a few pieces of zinc granules in a test tube.
2. Add abont 2 ml dil. Sulphuric acid to it.
Observation : A colourless gas is produced which burns with a pop sound when a burning match stick is brought near it.
The gas is hydrogen gas.
Inference : Zine metal reacts with dil. Sulphuric acid to give hydrogen gas.
Inference :
1. Zinc metal reacts with dil. H So to give hydrogen gas.2 4
2. This reaction is a displacement reaction.
Precautions :
1. Sulphuric acid should be handled carefully.
2. Burning of hydrogen gas should done carefully under the supervision of teacher.
Part (d) Materials Required : Lead nitrate crystals, hard glass test tube, test tube holder, burner.
Procedure : Heat a few crystals of lead nitrate in a hard glass test tube gently and then heat it strongly.
Observation : A reddish brown gas with pungent smell is produced and a yellow residue is left behind in test tube.
Inference : The gas produced is oxygen nitrogen dioxide and yellow residue lead oxide.
Inference :
1. Heating of lead nitrate gives solid lead oxide, gaseous nitrogen dioxide and oxygen.
2. This reaction is decomposition reaction.
18
Precautions :
1. Use hard glass test tube for this experiment.
2. Use test tube holder while heating.
3. Test tube should not face towards the observer
4. Do not inhale nitrogen dioxide gas.
Part (e)
Materials Required : Barium Chloride solution, test tube and test tube stand.
Procedure: Mix 10 ml of aq. Solution of sodium Sulphate is a test tube.
Observation : White precipitate (insoluble material) is formed.
Inference : In soluble barium Sulphate (white) is formed.
Inference :
1. Mixing of aq, Solutions of barium Chloride and Sodium Sulphate gives white precipitate of barium sulphate this is a precipitation reaction.
2. This is a double decomposition reaction.
Precautions :
1. Do not touch any solution.
2. The solutions should be prepared in distilled water.
19
CLASS IX
EXPERIMENT No: 5
AIM: To prepare stained temporary mounts of-
(a) Onion peel and
(b) Human cheek cells and to record observations and draw their labelled diagrams.
Materials Required : Onion bulb, slides, coverslips, two watchglasses, spatula toothpick, needle, brush, forceps, razor/blade, compound microscope, blotting paper, Methylene blue (Or Safranine) soln., glycerine and water.
Procedure : (a) Onion Peel
i. Cut on onion bulb into small pieces.
ii. Take out on epidermal peel from the inner side of a piece of bulb with the help of forcep.
iii. Keep this peel in watch glass having some water to avoid dehydration.
iv. Mix 1 or 2 drops of safranin or methylene blue in a small quantity of water taken is another watch glass.
v. Transfer the peel into it and leave it for about 3 minutes.
vi. Dip the peel in water to remove the excess stain and wash it two three times.
v. Transfer the peel into it and leave it for about 3 minutes.
vi. Dip the peel in water to remove the excess stain and wash it two three times.
vii. Take clean slide with a drop of glycerine in the middle.
viii. Using a brush transfer the washed and stanied peel on to this slide.
ix. Place a cover slip over it by slowly lowering it with a needle. Avoid the entry of air bubbles.
x. Remove excess glycerine from the edges of cover slip with the help of a piece of blotting paper.
xi. Observe the slide under the microscope first in low-power and then in high power.
xii. Draw the labelled diagram and not the features.
(method of taking out onion peel) (epidermal cells of onion)
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Observation Table :
S.No. Feature Observation
1. Arrangement of cells Compact (side by side) /loose
2. Shape of cells Spherical/oval/square/rectangalar
3. Inter Cellular spaces Present / absent
4. Cell wall Present / absent
5. Nucleus Present / absent
6. stained portion of cell Cell wall/ cytoplasm/nucleus
7. Unstained portion of cell Cell wall/ cytoplasm/nucleus
Inference :
Under low power of microscope the onion peel is observed as it is composed of cell. Each cell contains cell wall, enclosing the cytoplasm. Vacuoles and the nucleus are also observed embedded in the cytoplasm.
Precautions :
1. The folded peel piece should not be selected to study.
2. Always use this brush for transferring the material.
3. Spread the material uniformly in the middle of slide.
4. Remove excess stain and glycerine with the help of blotting paper.
5. While covering with coverslips, avoid the entry of air bubbles.
(b) Human cheek cells :
Procedure :
1. Take a clean tooth-pick or sterilized spatula and scrap gently the inner side of your cheek to get some epithelial cells.
2. Place the cheek scrap (with a brush) in watch glass containing water to clean it.
3. Add a drop of methylene blue extra stain and wait for 2-3 minutes.
4. From the material remove extra with the help of blotting / filter paper.
5. With the help of brush put this material in the middle of a clean slide and put a drop of glycerine over it.
6. Place a clan cover slip over the glycerine and remove the
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excess glycerine from the edges of cover slip with the help of a piece of blotting paper.
7. Examine the slide under microscope, first under low power and then under high power.
8. Observe and record the features.
Observation Table :
S.No. Feature Observation
1. Shape of cells --------------------------------
2. Inter cellular space Present / absent
3. Arrangement ---------------------------------
4. Cell wall Present / absent
5. Cell membrane Present / absent
6. Cell contents ---------------------------------
7. Vacuoles ---------------------------------
Inference :
The cells have very thin cell membrane called plasma membrane. jelly like cytoplasm and a prominent nucleus. Cells are polygonal and have irregular boundaries.
Precaution :
1. Cheek should be scrapped gently to prevent injury.
2. Avoid over staining of the material.
3. Spread the material on the slide to form a thin uniform layer.
4. While mounting the cover slip, avoid the entry of air bubbles.
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Class - X
EXPERIMENT No: 6
AIM : To identify parenchyma and sclerenchyma tissues in plants. striped muscle fibers and nerve cells in animals, from prepared slides and to draw their labeled diagrams.
Material Required : Compound microscope. Prepared slides of parenchyma, sclerenchyma, striped muscles and nerve fibers and prepared charts of plant and animal tissues.
Procedure :
1. Set permanent slides of parenchyma, sclerenchyma, striped muscle fibers and nerve cell one by one in the microscope and observe under compound microscope.
2. Compare your observation with the tissues shown in the chart.
3 Draw diagram of each tissue structure and label them.
Observation :
Parenchyma :
(1) Forms all soft tissue parts of plant body.
(2) Cells have thin cell wall.
(3) Cells are of different shapes and size
(4) Cells of this tissue are living.
(5) These cells help in photosynthesis, storage of food and mechanical support.
Sclerenchyma :
(1) Forms hard parts of the plant body.
(2) Cells have thick and lignified walls.
(3) Cells are usually elongated or polygonal in shape in cross section.
(4) Cells become dead when mature.
(5) These cells help to provide mechanical support.
Striped muscle fibers :
(1) Cells form all muscles attached with bones of the body.
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(2) Cells are elongated, cylindrical, unbranched and multi nucleated.
(3) Cells have transverse stripes formed by alternate dark and light band.
(4) The tissue helps movement of voluntary nature.
Nerve Cell :
(1) Cells are found in brain, spinal cord and nerves.
(2) Each nerve cell or neuron has a cell body, prominent nucleus, granular cytoplasm and branched finger like.
(3) The long projection is called axon.
(4) Dendrites receive information from previous nerve cell.
Precautions :
(1) Keep microscope in box when not in use.
(2) Clean the stage of microscope before and after use
(3) Do not tilt the microscope. Microscope should be hold vertical.
(4) Slide should be firmly clipped on the stage.
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Myellnsheath
Dendrltes
Synapticterminal
Cellbody
Nucleus
Axon
Class IX
EXPERIMENT No: 7
AIM : To separate the components of a mixture of sand, common salt and ammonium chloride (or camphor) by sublimation.
Materials Required : A funnel (glass), a china dish, a beaker (250 ml) Cotton plug, tripod stand, burner, wire gauge, filter paper and clamp stand.
Procedure : Sand, common salt and ammonium chloride form a heterogenous mixture and hence can be spearated by simple physical methods of separation the right order of separation is sublimation, filtration and evaporation various steps are.
i. Separation of Ammonium chloride by sublimation:
1. Take mixture of ammonium chloride, sand and common salt in china dish.
2. Set up an apparatus for sublimation as shown in fig (a)
3. Heat the mixture of china dish, ammonium chloride will be separated on the walls of inverted glass funnel.
ii. Spearation of sand by flteration :
1. The residue left in china dish in above step is sand and common salt.
2. Dissolve this aesidue mixture in water. Common salt will dissolve but not sand.
3. Set up as apparatus shown in fig (b) to filter snad from the mixture.
4. Sand is separated as residua leaving filtrate behind.
iii. Recovery of common safe by evaporation :
1. Heat the filterate left in above step to evaporate the water as shown fig ©
2. Let the sample of common salt to dry.
Result : Using the methods of separation in this sequence sublimation filteration and evaporation the ammonium chloride, sand and common salt have been separated respectively from their sample.
Precaution :
1. Heating sublimation & evaporation should be done carefully.
2. Care in required whilefitting so the the filter paper does not tear off.
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Figure : Separations of Component of mixture (Ammonium chloride, sand & Common salt)
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