03_ prac sc1 & sc 2

Foundation Practical Science 1& 2

TABLE OF EXPERIMENTS

SEMESTER 1Practical & Unit Experiment Titles No. of Credits

& hoursPractical Science 1

Unit 4

Experiment 1: Histology of Plant and Animal cells.Experiment 2: Introduction to Practical Chemistry.Experiment 3: Measurement and error estimation.

1 credit 30Hours(Tutorials + Practicals)

Practical Science 2

Unit 4

Experiment 1: Effect of enzyme and substrate concentration on the hydrolysis of sucrose.Experiment 2: Volumetric Analysis: Acid-Base.Experiment 3: Verifying the principle of conservation of linear momentum

1 credit, 30 Hours(Tutorials + Practicals)

Total number of credits 2 Credits

SEMESTER 2Practical & Unit Experiment Titles No. of Credits

& hoursPractical Science 1

Unit 9

Experiment 4: Dissection of mammalian circulatory system.Experiment 5: Volumetric analysis: Purity and stoichiometry.Experiment 6: Study the magnification of real image by a convex lens.


Practical Science 2

Unit 9

Experiment 4: Dissection of mammalian respiratory system.Experiment 5: Qualitative analysis: To determine the cations and anions of inorganic substancesExperiment 6: Study of Ohm’s Law and determine the total resistance of resistors in series and parallel.



SEMESTER 3Practical &Unit

Experiment Titles No. of Credits& hours

Practical Science 1

Unit 13

Experiment 7: Investigating the structure of flowers, Angiospermatophyta.Experiment 8: Acid, base and salt- ionic equilibrium.Experiment 9: Determine Young’s modulus by cantilever method.


Practical Science 2

Unit 13

Experiment 7: Examining slides of kidney and liver

Experiment 8: Separation Process - ChromatographyExperiment 9: Study the behaviour of a bar magnet in a varying magnetic fields and to estimate the horizontal component of the Earth’s magnetic field.



Grand Total 6 credits

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SEMESTER 1 Practical Science 1Experiment 1

Topic: Histology of Plant and Animal Cells

Purpose:1. To prepare slides of animal cells and plant cells using the correct staining

technique.2. To realise that cell is a basic unit of life.

Apparatus

Microscope Toothpick Microscope slide Coverslip Dropper ForcepsMethylene blue Iodine solution Onion

Procedure

(a) Observation of animal cells

1. Using a toothpick gently scrape off a thin layer of cells from the inside of your cheek.

2. Mount the scrapings in a drop of methylene blue solution on a slide.3. Examine the specimen under low power objective lens followed by high power

objective lens.4. Draw the cheek cells and label the following parts: nucleus, nuclear membrane,

chromatin granules, cell membrane, and cytoplasm.

(b) Observation of plant cells

1. Using a pair of forceps, peel off the epidermal layer of onion scale leaf.2. Mount the epidermal layer in a drop of water on a slide. 3. Examine the specimen under a microscope.4. Stain the onion scale leaf epidermis with iodine solution. Then examine the

specimen under the microscope.5. Draw the onion scale leaf epidermal cells. Label the cell wall, cell membrane,

cytoplasm, nucleus, chromosome, nucleolus, and vacuole.

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Questions

1. Name the type of cells which lines the inner cheek.

..................................................................................................................................

2. What is the effect of methylene blue solution on the cheek cells?

..................................................................................................................................

3. Why is it that the onion scale leaf cells do not contain chloroplast?

..................................................................................................................................

4. State two differences between animal cells and plant cells.

.................................................................................................................................

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Topic: Introduction to Practical Chemistry

Purpose: To understand the rules and regulations in the chemistry laboratory and laboratory report format

Actitivity I

(a) Discuss with your lecturer the rules and regulations that have to be followed while you are in the chemistry laboratory.

(b) Make sure that you understand these rules and then sign the rules and regulations document given to you.

(c) Discuss with your lecturer the safety rules for the laboratory.

Activity II

(a) Study the laboratory report format suggested and discuss with your lecturer the details included in it.

Activity III

(a) Discuss and practice with your lecturer the techniques in handling the following:

Burette Pipette Measuring cylinder thermometer Weighing chemicals Pouring concentrated acid, alkali and solution Preparation of solution

Questions:1. Why is an acid added to water and not water to acid?

2. What safety measures would you take when handling corrosive chemicals?

3. With reference to the labels found on the chemicals in the laboratory, draw and identify the meaning of the symbols.

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Topic: Measurement and Error Estimation

Purpose: To determine the density of(i) Glass (iii) PVC(ii) Steel (iv) Cooking oil

Theory:The density of a substance is the mass per unit volume of the substance, i.e.

= …….(1)

Before the density of a substance could be determined, it is necessary to measure the mass and volume of a sample of the substance. Using relationship (1), the density of the substance could be calculated.

The S.I. unit for density is kgm-3. We can also use the unit gcm-3 for density.

Apparatus:(i) PVC tube

(ii) Steel wire (SWG 18) of approximate length 50 cm (iii) Any kind of cooking oil about 200 cm3 (iv) A glass block(v) A meter rule

(vi) A pair of vernier calipers (vii) Triple beam balance or other suitable balance (to be shared)

(viii) A micrometer screw gauge (ix) A 250 cm3 measuring cylinder (x) A 500 cm3 beaker

Procedure:

(I) To determine the density of Glass

(a) Find the probable scale measurement error of the vernier calipers.

(b) Measure the length p, breadth b, and thickness t, of a glass block with

a vernier calipers. (taking into account the zero error)

(c) Weigh the glass block to get the mass m, and find the probable scale

measurement error of the weighing machine.

(d) Calculate the density of glass

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(II) To determine the density of PVC

(a) Measure the external and internal diameters of a PVC tube at different parts of the tube. Determine the average external and internal diameters of the tube.

(b) Measure the length at different parts of the tube. Determine the average length.

(c) Weigh the tube using a triple beam balance or other suitable weighing machine and find the probable scale measurement error.

(d) Calculate the density of PVC.

(III) To determine the density of steel

(a) Find the probable measurement scale error of the micrometer screw gauge.

(b) Measure the diameter at different parts of the wire. Determine the average diameter. Measure the length of a steel wire.

(c) Weigh the wire using a triple beam balance or other suitable weighing machine and find the probable scale measurement error. (d) Calculate the density of steel.

(IV) To determine the density of cooking oil

(a) Weigh an empty measuring cylinder using a triple beam balance or other suitable weighing machine and find the probable scale measurement error.(b) Measure 200 cm 3 of cooking oil using the measuring cylinder. (c) Weigh the filled measuring cylinder. (d) Calculate the density of the cooking oil.

Formulae that facilitate calculations

(I) Volume of glass block, V= p x b x t

Error in V, V = { + + } V

Density, =

Error in , = { + }

State the final value of the density of the glass block with it's probable error.

(II) Volume of PVC tube = cross-sectional area x length

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= (a2 - b2) x l

a = external diameter, b = internal diameter, and l = length

(III) Volume of steel wire = cross-sectional area x length

= a2l

a = diameter, and l = length of steel wire

(IV) Mass of oil = M1 - M2

M1 = mass of cylinder + cooking oil M2 = mass of cylinder

Data recording and Analysis

(I) State the value of length p, breadth b, thickness t and mass m of a glass

block

with their probable errors.

p = ……………. ……………… m

b = ……………. ……………… m

t = ……………. ……………… m

m = ……………. ……………… m

(II) Table for recording the external and internal diameter of PVC pipe.

No. Readings Diameter

(mm)

External, a Internal, b

Find the average value of a = ……… ………… m and

b = ……… ………… m

l = ……… ………… m

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(III) Table for recording the diameter of wire.

No. Readings Diameter, d

(mm)

Radius, r =

(mm)

Find the average value of r = ……………. ……………… m

m = ……………. ……………… kg

(IV) Record the weight of the empty measuring cylinder:

M2 = …………… kg and the weight of measur ing cyl inder wi th cooking oi l M1 = ……………. kg

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SEMESTER 1 Practical Science 2 Experiment 1

Topic: Effect of enzyme and substrate concentration on the hydrolysis of sucrose

Purpose:

1. To investigate the effect of temperature on enzyme-catalysed reactions2. To determine the optimal temperature of enzymic reactions3. To determine the temperature quotient, Q10, of an enzyme-controlled reaction

Apparatus

250 cm3 beakers (5 units)Thermometer Test-tubes (10 units) White tileDropperStopwatch

30 cm3 of 1 % starch solution Iodine solution

Procedure

1. Prepare saliva solution by spitting saliva into a clean beaker and diluting it with equal amount of distilled water. (Remember to rinse your mouth first.)

2. Prepare five beakers of water baths at the following temperatures: 0 °C, 20 °C, 37 °C, 50 °C, and 65° C, and label the baths A to E. The temperature of the water bath must be kept constant by adding hot/cold water into it.

3. Place two test-tubes labelled X and Y into water bath A. Put 4 cm 3 starch solution into test-tube X and 3 cm3 saliva solution into test-tube Y. Leave it for 5 minutes to stabilise the temperature. Then add the saliva solution from test-tube Y to the starch solution in test-tube X to start the reaction.

4. Start the stopwatch.

5. Every minute, take out a drop of solution from test-tube Y and test it with a drop of iodine on a white tile.

6. Repeat steps 3 to 5 for water baths B, C, D and E.

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7. Conduct iodine tests at a shorter interval as and when the reaction is nearing completion.

8. The time taken for each complete hydrolysis is recorded in the table below.

Results

Test-tube

Temperature (oC)

Time taken for complete hydrolysis(minutes, t)

Rate of reactions1/t

A 0

B 20

C 37

D 50

E 65

Questions

1. Plot a graph of reaction rate (1/t) against temperature.

2. (i) Calculate the temperature coefficient, Q10, between 30 °C and 40 °C. (ii) What conclusion can you draw from the value of Q10 in question 2 (i)?

3. Describe how temperature affects enzyme –catalysed biochemical reactions.

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SEMESTER 1 Practical Science 2

Experiment 2

Topic: Volumetric analysis: acid- base

Purpose: To determine the exact concentration of a mineral acid, HX, and todetermine the relative atomic mass of the element

Theory:

Acid-base titration is a useful method in experimental chemistry to determine the molarity of a solution, standardizing solutions and in the determination of molecular mass of an unknown. In an acid-base titration, the equilvalent point is attained when the amount of acid and base present exactly neutralizes one another. At this point neither the acid nor the alkali is present in excess. The solution will consist of salt and water only. The end-point of the titration is reached when the indicator changes colour. Thus, in an acid-base titration, the choice of the indicator is important. The end-point indicated by the indicator must coincide with the equivalent point.

Apparatus:(i) A 25 cm3 pipette (ii) A pipette filler(iii) Three titration flasks(iv) A 50 cm3 burette(v) A white tile(vi) A wash bottle filled with distilled water

Chemicals required : (i) KA 1 is a mineral acid, HX(ii) KA 2 is a solution containing 1.70 g of OH- ions per dm3

(iii) Phenolphthalein as an indicatorProcedure:

(a) Pipette 25.0 cm3 of KA 2 into a titration flask. Add two or three drops of phenolphthalein indicator and titrate this solution with KA 1.

(b) Record your readings in the table below.

(c) Repeat the titration as many times as you think necessary to achieve accurate results.

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M1V1 = M2V2

Results:

Titration Number Rough Accurate

1 2 3

Final Reading/cm3

Final Reading/cm3

Volume of KA 1 /cm3

25 cm3 of KA 2 required …………….. cm3 of KA 1 for a complete reaction.

Questions:

1. Calculate the average titre value.

2. Calculate the concentration, in moldm-3 , of solution KA 2.

3. Write a balanced ionic equation for the reaction between solution KA 1 and solution KA 2.

4. Calculate the concentration, in moldm-3 , of mineral acid HX in solution KA 1.

5. If the concentration of mineral acid in solution KA 2 is 20.1 gdm -3, calculate the relative molecular mass of HX.

6. Using the answer to (5), determine the relative atomic mass of element X.

7. Suggest an identity for element X.

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Experiment 3

Topic: Kinematics and Dynamics

Purpose: To verify the principle of conservation of linear momentum for a collision of two bodies of equal mass.

Theory:Figure 1 below shows the bob of a pendulum being released from P to Q.

Figure1

If v is the velocity of the bob at Q and m is the mass of the bob, then,

mgh = m v2.................(1)If z = horizontal displacement of bob from Q L = length of pendulum and = angular displacement of the bob, then

h = L(1- kos )

=L (2sin2 )

For smaller than 15° , sin2 = ( 2 ; z = L

then, h= L 2 =

from equation (1), v2 = 2gh,

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then v2 = and kinetic energy Ek = m v2 = v z and kinetic energy Ek cc z2

Apparatus:(i) Hooking plank(ii) Two bobs equal mass(iii) Two threads of length about 2 m

(iv) Two retort stands and clamps (v) A metal wire as indicator

(vi) A screen to act as marker to the distance of collision (vii) A meter rule

(viii) Plasticine (ix) A pair of vernier calipers (x) Blocks for raising the height of retort stands

Procedure:

(a) Set up the apparatus as shown in Figure 2.

Figure 2

(b) Using a pair of vernier calipers, measure the diameter of the pendulum bob.(c) Hook the pendulum bob on the hooking plank as shown in the diagram above and make sure that the center of the two pendulum

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bobs rest at the same level and not less than 80 cm from the hooking plank.(d) Place a meter rule below the bobs. Adjust the meter rule so that the 50 cm mark is just below the point of contact of the bobs.(e) Move one of the bobs away, and determine the position of the centre of the other bob and record the corresponding reading on the meter rule as X01. Repeat the process, and record the position of the centre of the other bob as X02.(f) Displace one of the bobs about 20 cm away. Record the position of the centre of the bob as X1. Release the bob so as to make direct head-on collision with the other bob (The first bob should be almost at rest after the head-on collision). (g) If it is a head-on collision, record the position of the screen that serves as a marker for the distance of collision. Repeat the process if the collision is not a head-on collision.

(h) Record the position of the centre of the second bob, X2, if the collision is a head-on collision. (i) Repeat steps (e) through (g) for displacements between 20 cm to 10 cm (j) Record all your readings, and tabulate X1, Z1 = (X1 – X01), (Z1)2, X2,

Z2 = (X2 – X02), (Z2)2, and (Z2/Z1)2

(k) Stick a small lump of plasticine on one of the pendulum bobs and repeat steps (e) through (g). After the collision, both the pendulum bobs should move as one body. (l) Record all your readings, and tabulate X'1, Z'1= (X'1 - X'01), (Z')2, X'2,

Z'2 = (X'2 -X'02), (Z'2)2, and (Z'2/Z’1)2 . (m) From the results obtained, deduce a conclusion on the momentum and kinetic energy of the two systems.

State whether the collisions in the first and second systems are elastic or not.

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Experiment 4

Topic : Dissection of mammalian circulatory system

Purpose:1. To follow instructions correctly so that the thoracic area can be displayed to

maximum advantage2. To identify the organs in the thoracic cavity3. To identify the position of the main blood vessels (veins and arteries)

and their branches4. To produce labeled drawings from the display 5. To state the scale of drawing accurately

Theory:

The circulatory system is a transport system that carries things to and from different places in the body. Mammalian circulatory system is a double circulation. That means that blood passes through the heart twice as it goes once round the body. The right side of the heart pumps blood to the lungs to collect oxygen and get rid of carbon dioxide. The left side of the heart pumps blood to the rest of the body to supply cells with oxygen and pick up of carbon dioxide and other waste.

The heart and the major blood vessels of the rat is illustrated in Figure 4 and 5.

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Figure 4:

Venous system of the rat, ventral view. Only the major vein are shown.

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Figure 5:

Arterial system of the rat, ventral view. Only the major arteries are shown.

Apparatus and materials

Dissecting instruments RatDissecting board Pin

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Procedure

1. Pin a rat to the dissecting board with the ventral surface uppermost.

2. Make a mid-ventral incision through the skin and cut the skin towards the mouth and then towards the posterior.

3. Using fingers or scalpel, free the skin from the underlying body wall. Pin back the skin.

4. Open up the body wall in the abdominal region of animal.

5. Pull the xiphoid cartilage downward and fix its position with a thread pulled back and pinned to the dissecting board in between the legs.

6. Using scissors make an incision by cutting a little anterior into the diaphragm, into the thoracic cavity. Continue cutting the sidewall down towards the dorsal surface. Take care not to cut too far down.

7. Continue cutting the sidewalls towards the thoracic apex. You will be cutting the ribs, intercostal muscles, and pectoral muscles. (Make sure that the tip of the scissors is always pointing upwards to avoid damaging the internal organs).

8. Once the thoracic wall is free lift up the whole ventral thoracic wall as if you are lifting a cover.

9. Remove the ventral thoracic wall by cutting the tissues near the apex.

10. Lift up the cut pectoral muscles. Carefully separate the muscles from the thoracic wall without damaging the underlying veins. Once the deeper muscles have been removed, you will be able to see the clavicle. Cut this bone in the middle taking care not to damage nearby veins.

11. Cut and remove the neck muscles to expose the trachea and larynx.

12. Remove the thymus gland and superfluous fat from the displayed section.

13. Push and pin the heart and lungs to the right side of the animal.

14. Examine and identify the veins on only the left or the right side of the animal.

15. Make a large labeled drawing to show the veins in the thoracic region of the

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animal. State the scale of your drawing. Drawing

Scale of drawing ……………………………………….

16. Examine and identify the arteries on both sides of the thorax. Make a large labeled drawing to display the arteries on both sides of the thorax. State the scale of your drawing.

Drawing

Scale of drawing ………………………………….

17. Cut the anterior section of the larynx. Using forceps, hold the cut end of the larynx, and then loosen the larynx and trachea from the tissues underlying it by cutting off some of the connective tissues where necessary. Determine the main blood vessels, which pass through the diaphragm and cut these vessels at the region near the anterior diaphragm. Cut away tissues where necessary to free and remove the heart, lungs, trachea, and main blood vessels together.

18. Remove each lung by cutting the pulmonary arteries and veins. Cut nearest to the lungs so that the maximum length of each blood vessel can be displayed.

19. Draw a dorsal view of the heart with its blood vessels attached to it.

Drawing

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Experiment 5

Topic: Volumetric analysis- Purity and stoichiometry

Purpose: To determine the purity of a sample of sodium sulphite crystals

Theory:The sulphite ion can be oxidized quantitatively to the sulphate ion by iodine the presence of the hydrogen carbonate ion.

SO3 2- + I2 SO4 2- + 2 HI

2 HI + 2HCO3 - 2I - + 2 H2O + 2 CO2

If a solution of sodium sulphite is added to an excess of a standard solution of iodine, the excess iodine in the resulting solution can be titrated with a standard solution of sodium thiosulphate (VI). Hence the concentration of sodium sulphite can be determined.

Apparatus:(i) A 25 cm3 pipette(ii) A pipette filler(iii) Three titration flasks(iv) A 50 cm3 burette(v) A 50 cm3 pipette(vi) A white tile(vii) A retort stand with clamp

(viii) A wash bottle filled with distilled water

Chemicals required:

(i) KA 1 is a 0.025 mol dm-3 aqueous iodine solution .(ii) KA 2 is a solution containing 12.41 g of sodium thiosulphate (VI) per dm3. (iii) KA 3 is a solution containing 3.15 g anhydrous sodium sulphite, Na2SO3, per dm3.(iv) KA 4 is a 2 g packet of sodium hydrogen carbonate.

Procedure:

(a) Pipette 50.0 cm3 of KA 1 into a titration flask.

(b) Using another pipette, place 25.0 cm3 of KA 3 slowly into this titration flask

21


containing KA 1 and shake. (c) Add 2 g of KA 4 and shake the flask again. Titrate the resulting solution with KA 2 using starch as indicator.

(d) Repeat the titration as many times as you think necessary to achieve accurate results.


M1V1 = M2V2

Results:

Titration Number Rough Accurate

1 2 3

Final Reading/cm3

Final Reading/cm3

Volume of KA 2 /cm3

50.0 cm3 of KA 1 required …………….. cm3 of KA 2 for a complete reaction.

Questions:

1. Calculate the average titre value.

2. Write a balanced equation for the reaction between iodine and the thiosulphate (VI) ion.

3. Calculate the volume of I2 that did not react with the sulphite ions.

4. Using your answer to (3), calculate the volume of I2 that reacted with the sulphite ions.

5. Using your answer to (4),

(a) Calculate the concentration, in mol dm-3, of the sulphite ions in solution KA 3.

(b) Calculate the mass of Na2SO3 present in 250 cm3 of KA 3.

3. Using your answer to 5 (b), calculate the percentage purity of Na2SO3 that you used.

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Experiment 6

Topic: Geometrical Optics

Purpose: To study the magnification of real image by a convex lens

Theory:

From lens equation + =

+ 1 =

m = - 1

where m = , m = linear magnification.

The graph of m against v is a straight line.Equation also shows that m increases with v; m = 1 when v = 2f.

Apparatus:(i) A convex lens(ii) A short transparent ruler

(iii) A card with a square hole at the centre (iv) A screen (v) A bulb as light source (vi) A meter rule

(vii) Plasticine

Procedure:

(a) Estimate the focal length of the convex lens.(b) Set up the apparatus as in Figure 25.(c) Choose a length of 2 cm on the scale of the transparent ruler as object.

Therefore, the size of the object h = 2.0 cm.

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Figure 25

(d) Vary the position of the object. Determine v and the size H of the image on the screen.

(e) Calculate the linear magnification m, and plot a graph of m against v. (f) From the graph, determine the focal length f of the lens.

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Experiment 4

Topic : Dissection of the mammalian respiratory system Purpose:

1. To train students to dissect small mammals2. To train students how to use dissecting instruments3. To increase students' skill in displaying, drawing and labeling respiratory

organs4. To enable students to examine the structures of the main organs 5. involved in respiration (lungs, trachea, diaphragm, rib cage, and intercostals 6. muscles)7. To increase students' understanding of the process of gas exchange in

animals

Theory :The main organs involved in breathing are the lungs, trachea, diaphragm, ribcage and the intercostals muscles. Contraction and expansion of the intercostals muscles and the muscles of the diaphragm will move the diaphragm and ribcage so that the volume of the thorax changes. This then will result to the flow of air moving into the lung or out from the lung.

The diagrams (Figure 1 and Figure 2) will guide you to do this practical.

Figure 1:

Stage in the dissection of the breathing apparatus of the rat.

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Figure 2:

The glottis and related structures of the rat


RatsDissecting instruments Dissecting board Hand lens x 10 Transparent plastic ruler Thread

Procedure

1. Pin the rat to the dissecting board with the ventral surface uppermost.

2. Make a mid-ventral incision through the skin and cut forward as far as the lower jaw and then backwards to the anus.

3. Holding the skin with a pair of forceps, cut away the connective tissues between the skin and the body wall as far as possible around the animal's body and pin back the skin.

4. Cut away the ventral and lateral thoracic walls to expose the thoracic cavity.

5. Remove the thymus gland.

6. Cut away muscles and tissues of the neck to expose the trachea and larynx.

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7. Cut above the larynx. Cut off the connective tissues attached to the trachea.

8. Remove the heart, lungs, trachea, esophagus, and larynx together. 9. Carefully separate the esophagus from the heart. Pin the larynx, trachea, and

lungs to the board.

10. Make a large labeled drawing of the structures you have taken out.

Drawing

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Questions

1(a) How many pairs of ribs does this animal have?

.................................................................................................................................(b) How does the rib cage function during gas exchange in this animal?

................................................................................................................................. ..................................................................................................................................................................................................................................................................

2(a) Describe the appearance and characteristic of a diaphragm.

.................................................................................................................................

.................................................................................................................................

(b) What is the importance of this characteristic of the diaphragm in relation to its function during gas exchange? .........................................................................................................................................................................................................................................................................................................................................................................................................

3. Describe the appearance of the left and right lungs.

.....................................................................................................................................

.................................................................................................................................

4. Cut a part of a lung. Examine the cut surface using a hand lens. Describe what you can see with regard to the texture of the lung.

...................................................................................................................................

...................................................................................................................................

5. Measure the length of the trachea to the nearest mm, from the larynx to the pointwhere it branches out into two bronchi.

.....................................................................................................................................

.....................................................................................................................................

...............................................................................................................................


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Experiment 5Topic : Qualitative analysis

Purpose : To determine the cations and anions of inorganic substances

Theory : Chemical analysis is the process by which we can find out the composition of a substance by breaking it down into its constituents. Qualitative analysis is used to find the elements present in a given compound or mixture. Reactions of the cations and anions with specific reagents enable its identity to be obtained.

Procedure :

(a) Solids KA 1 and KA 2 are simple salts. Carry out the-following experiments with solid KA 1 to identify its cation and anion.

(b) You are then required to plan and to carry out a few experiments to identify the cation and anion present in solid KA 2.

In all the experiments, the reagent should be added gradually until no further change is observed. Record your observations and the deductions you make from them in the spaces provided. Deduce what you can about KA 1 and KA 2. Observations should include details of colour changes, precipitates, and tests on gases evolved, and you should indicate clearly at which stage in a test a change occurs.

Tests on KA 1

Test Observation Deduction

(c) Add dilute hydrochloric acid to a small

amount of solid KA 1, then warm gently.

(d) Dissolve solid KA 1 in distilled water and filter. Use separate portions of the filtrate for tests (i) to (vi).

(i) Add aqueous sodium hydroxide, then in

excess.(ii) Add aqueous ammonia, then in excess

followed by aqueous ammonium chloride.

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(iii) Add aqueous iron(III) chloride, then warm.

(iv) Add aqueous silver nitrate, followed by dilute nitric acid.

(v) Add aqueous disodium hydrogen phosphate.

(vi) Add aqueous potassium chromate(VI) followed by dilute hydrochloric acid.

Identity of KA 1:............................................................................................................

Repeat the same procedure to identify KA 2

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Experiment 6

Topic : Electric Current

Purpose: To study Ohm's law and to determine the total resistance of resistors in series and parallel.

Theory: An applied voltage V, causes an electrical current I, in a conductor, the current is directly proportional to the voltage:

I VFor many materials, the relationship between current, voltage and resistance is given by

I = or V = IR,

this equation is called Ohm’s law. From the equation, the resistance, R can be

written as R = . The unit of resistance is called an Ohm ().

When the resistances are connected is series, the total voltage drop around a circuit is equal to the sum of the individual voltage drops across the resistors. That is,

V =V1 + V2 + V3 = IR1 + IR2 + IR3 = I(R1 + R2 + R3) = IRs

The equivalent resistance Rs = R1 + R2 + R3

For any number of resistor in series, the equivalent resistance can be extended as:

Rs = R1 + R2 + R3 + .........Rn , where n = number of resistor.When resistors are connected in parallel, the current from the battery divides among the different paths. Since the voltage drop, V, across each resistor is the same, by Ohm’s law;

I = I1 + I2 + I3 = + + = V =

Thus, the equivalent resistance Rp of three resistors in parallel is given by

=

For any number of resistors in parallel, the equivalent resistance, Rp can be generalized as;

= , where n = the number of resistors in parallel.

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Apparatus:(i) DC supply from 3 dry cells/power-pack

(ii) Three carbon resistors of the same resistance (iii) An ammeter

(iv) A voltmeter(v) A rheostat (0 - 20 )(vi) An on - off switch(vii) Six 50 cm connecting wires(viii) Two connectors for connecting resistors(ix) A small screw driver

Procedure:

(a) Set up the circuit as shown in Figure 7a below. Connect the three resistors in series.

Figure 7a

(b) Use the circuit to study the variation of V with I , where V is the reading of the voltmeter and I is the reading of the ammeter.

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R1 R2 R3


(c) From your graph of V against I, deduce the total resistance of resistors in series in the circuit.

(d) Connect up the circuit as shown in Figure 7b.

Figure 7b

(e) Repeat steps (b) and (c).(f) From your graph of V against I, determine the total resistance of resistors

in parallel in the circuit.

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Experiment 7

Topic : Investigating the structure of flowers, Angiospermatophyta.

Purpose :

A. To investigate the morphology of the Flame of the Forest (Delonix regia) flower and its relation to its functions

Theory:

A flower consists of whorls of modified leaves which collectively produce, protect and ensure the union of the gametes. The whorls are attached to a receptacle, the expanded end of the flower stalk. The parts of the flower from the outside to inside are calyx, corolla, androecium, and gynoecium.

There is a wide variation in flower structure. Flowers of different species may differ in the numbers, arrangement and the degree of the fusion of the component parts.

Radially symmetrical flowers are called actinomorphic and bilaterially symmetrical flowers are called zygomorphic flowers.

Floral diagram provides a plan of the flower as viewed from above. It looks like a diagrammatic cross-section.

If a bract, a leaf-like structure immediately beneath the flower, is present it should be facing you, the flower stalk should be furthest away and the main stem of the plant should be at the top of the flower. You will probably cut a cross-section of the ovary so that you can show the position of the ovules on the diagram. If the petals, sepals or stamens are joined, link them with simple brackets. If the stamens arise from the petals, link them with radial lines.

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Figure 8.1: The two tpyes of symmetry found in flowers. The dotted lines indicated the planes through which the flowers can be cut so as to give two equal and opposite halves.


Figure 8.2: Three representations of the structure of the same flower

Apparatus and Materials

Flame of the Forest flowers A sharp scalpel/razor bladeHand lens

ProcedureCut the flower into two equal halves using a sharp scalpel. Make a large labeled drawing of the dissected flower as well as the floral diagram. State the scale of your drawing.

Drawing

Flame of the Forest flower

Scale …………………………

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B. To investigate the morphology of the orchid flower (Dendrobium) and its relation to its function.

Apparatus and Materials

Orchid flowers A sharp scalpelHand lens

ProcedureCut the flower into two equal halves using a sharp scalpel. Make a large labeled drawing of the dissected flower as well as the floral diagram of the flower. State the scale of your drawing.

Drawing

Orchid flower

Scale …………………………

Questions

1. State the family, type of ovary, and the symmetry of both flowers being investigated.

Flame of the Forest Orchid

FamilyType of ovarySymmetry of flower

2. What are the special features, which both flowers have to ensure the success of their fertilization process?

………………………………………………………………………………………….

………………………………………………………………………………………….

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Topic : Acid, base and salt : ionic equilibrium Purpose : To determine the solubility product, KSp, of lead(II) iodide

Theory : Research on sparingly soluble salt needs to take into consideration the equilibrium phenomenon involved. The equilibrium constant or solubility product, Ksp, for such systems can be obtained by taking into account the concentration of the ions of solutes in saturated solutions. The Ksp for a sparingly soluble salt AxBy at a fixed temperature can be obtained by :

Ksp = [xAy+] [ y Ax+]

The greater the value of the Ksp the more soluble is the salt.

Materials : KA 1 is 0.25 mol dm-3 aqueous lead(II) nitrate.

KA 2 is 0.10 mol dm -3 aqueous lead(II) nitrate.



KA 5 is 0.01 mol dm-3 aqueous potassium iodide

Procedure: (a) Titrate 25.0 cm3 of KA1 with KA5. The end point is achieved when a precipitate appears. Repeat experiment with KA2, KA 3, and KA 4.

Results : (b) Record and complete your readings in the table below.

Solution KA 1 KA 2 KA 3 KA 4

[Pb(N03)2] mol dm-3 0.25 0.10 0.05 0.02

[KI] mol dm-3 0.01 0.01 0.01 0.01

Volume of Pb(N03)2, Vo/cm3

Volume of KI, V /cm3

( Vo + V) /cm3

Questions :(c) From your titre values, calculate the concentration of lead(II) ions and iodide ions at end point for each of solutions KA 1, KA 2, KA 3, and KA 4. Enter the concentration values obtained in the table below and complete the table.

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Solution KA 1 KA 2 KA 3 KA 4

[ Pb2+]

[ I- ]

[ P [ Pb2+][ I - ]2

(d) Sketch a graph of [Pb2+][I-]2 against [Pb2+].

(e) Comment on the values of the ionic product of PbI2 .

(f) Calculate an average value for the solubility product of lead(II)iodide.

(g) What is the effect of increasing the concentration of lead(II) ions on Ksp of PbI2?

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Experiment 9

Topic : Deformation of Solids

Purpose: To determine Young's modulus by cantilever method.

Theory:

Figure 8

L = length,

b = width, and

t = thickness of meter rule

The Young's modulus E of wood of the meter rule is given by E = ,

where M = mass of the slotted masses, d = deflection of the end of the ruler.

E = , s = gradient of graph d against M.

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Apparatus:

(i) A meter rule(ii) A half-meter rule (iii) A 'G' clamp (iv) A retort stand and clamp(v) Thread(vi) A 50 g slotted mass hanger (vii) A set of 20 g slotted masses(viii) A wooden block(ix) A pair of vernier calipers(x) A micrometer screw gauge

Procedure:

(a) Determine the length d for different values M of slotted masses used.

(b) Plot a graph of d against M.

(c) Calculate the Young modulus E of wood of the meter rule.


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Experiment 7

Topic : Examining slides of liver and kidney

Purpose:

1. To understand the structures of the liver and kidney so as to reinforce the theoretical understanding of the functions of the two organs in homeostasis

2. To understand the important structures in the liver and kidney which function in homeostasis

Theory: - The liver has many functions. Two main ones are;

● It secretes bile into the bile duct down which it flows, via a gall bladder, to the duodenum

● It regulates the amounts of blood sugar, lipids and amino acids by removing them from the blood stream or adding them to it, as appropriate.

It receives blood from two sources: oxygenated blood is taken to it via hepatic artery, blood rich in food substances via the hepatic portal vein. Blood is removed from the liver via the hepatic vein.

Refer to the diagram provided to guide you to the examine the slides (Figure 6).

Figure 6: Microscopic structure of the liver

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The kidney extracts unwanted substances from the blood, adjusting the blood‘s composition so that the it has the right osmotic and ionic concentration. The basic functional unit of the kidney is the nephron.

Refer to the diagram provided to guide you to the examine the slides (Figure 7.1 to 7.4).

Figure 7.1: Mammalian kidney sectioned to show the position of the nephrons and their blood supply. For clarity the nephron and blood vessels are shown separately; in reality they are intimately associated. A Bowman’s capsule and its associated glomerulus together constitute a Malphigian body. Note how the nephron ans its blood supply are orientated relative to the kidney as a whole, and also which parts of the nephron are in the cortex and which ones in the medulla.

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Figure 7.2: A Malpighian body as it may appear in a microscope section of the kidney. This drawing is idealised; rarely would a section pass through the afferent and efferent vessels and the proximal tubule.

Figure 7.3: Tubules, collecting duct and capilllaries as they appear in a microscopic section of the cortex of the kidney. Plasma membranes are not usually visible between adjacent cells in the walls of the tubules, hence their absence in this drawing. Red blood cells are sometimes present in the blood capillaries.



MicroscopePrepared slides of liver and kidney

Procedure:

1. Observe the slides under low power microscope to determine the plan of general tissue distribution. Examine the detailed structures under high power microscope by observing the form of the cells and other features.

2. Make two drawings for each slide.a. Drawing of the outline as seen under low power microscope. Do not

draw any cells.b. Detailed drawing as seen under high power microscope showing

accurate cell/ tissue characteristics. Draw a few cells only.

3. Each drawing must have a complete title which gives the following information: Name of organ, type of section, and magnification.

4. Examine prepared slides of liver and kidney. Make a large labeled plan drawing of each tissue.

5. Note that the liver consists of many lobules. For each lobules, liver cells (liver cord) are arranged in rows in between sinusoids which are blood channels. Bile canaliculus lies in between liver cords. Central vein is a tributary of the hepatic vein. The portal area contains the bile ducts, branches of hepatic artery, and branches of hepatic portal vein.

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Figure 7.4: The loop of Henle, collecting duct and capillaries as they appear in a microscopic section of the medula of the kidney. The thin limb is the top two-thirds of the descending limb of the loop of Henle; the thick limb is the descending limb plus the whole of the ascending limb. Plasma membranes are not usually visible between adjacent cells in the walls of the loop of Henle, hence their absence in this drawing.


6. Examine kidney slide under low power microscope and identify the characteristics of the various structures found in this organ. Observe the capsule (connective tissues), pelvis, cortex and medulla. Note that the Malphigian corpuscle consists of glomerulus and Bowman's capsule, the cuboid epithelial cells of the proximal convoluted tubules have brush borders while the distal convoluted tubules have bigger lumen and without brush borders.

7. State the magnification of your drawing.Plan drawing

Liver slide

Magnification of drawing………………………………………..

Kidney slide

Magnification of drawing ………………………………

High power drawingLiver slide


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Kidney slide


Questions

1. What are the blood vessels, which feed the liver? .................................................................................................................................

2. Explain the term emulsification. ................................................................................................................................................................................................................................................................................................................................................................................................

3. State the name of the two types of bile salt.................................................................................................................................

4. Why is bile salt not considered as an enzyme?

................................................................................................................................

................................................................................................................................

5. Why do mammals have to get rid of their excretory products?

................................................................................................................................

................................................................................................................................

................................................................................................................................

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Experiment 8

Topic : Separation Process - ChromatographyPurpose : To separate and to identify the colours found in a type of commercial food dye

Theory: Chromatography is a technique used to separate the different components in a mixture. All chromatography techniques consists of two major components; the stationary phase and the mobile phase. The method consists of dissolving the mixture in a suitable solvent and which is then carried over the surface of the stationary phase. Separation is possible because different substances have different degrees of adsorption or solubility between the stationary phase and the mobile phase. The components will move along the stationary phase at different speeds, and are thus separated. In paper chromatography, the stationary phase is the strip of chromatography paper and the mobile phase is suitable solvent.

By comparing the Rf values of the components with Rf values of known substances, the components in the mixture can be identified. The value of Rf for each of the component is calculated using the formula: Rf = (distance moved by the component] / (distance moved by the solvent)

Materials : 1. food dye

2. ethanol

Procedure : (a) Prepare 100 cm3 of ethanol and water solvent in the ratio of 3:1. Pour this solvent into a 1 dm3 tall container. Cover the mouth of the container with plastic and leave it to stand for 30 minutes.

On a strip of filter paper measuring about 4 cm wide and 38 cm long, mark lightly a line with a pencil about 2 cm from one end. Using a fine glass capillary pipette, spot the solution of food dye onto a marked spot in the middle of the line as shown in the diagram below. Dry the spot with a hair dryer.

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Suspend this paper in the tall container with its lower end touching the solvent. Ensure that the pencil line is above the solvent level and the sides of the filter paper do not touch the walls of the high container as shown in the diagram below.

Leave the apparatus to stand for 1 to 2 hours. Then remove this filter paper and mark the position of the solvent front immediately. Dry the paper with a hair dryer.

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Obtain the Rf values for each of the spots separated. Measure the distance moved by the solvent front and the distance moved by the colour components from the starting line.

Results : (b) Record your results in the table below.

Substance Component Colour of component

Distance of movement of component/cm

Distance of solvent front/cm

Rf

Questions

(c) Using your results from the table above and information given by your teacher, identify the colour components in the sample of food dye provided.(d) In this paper chromatography experiment, state the substance that functions as the (i)stationary phase, (ii) mobile phase.(e) Explain how you would ensure that the drop of food dye at the starting line is concentrated and small in size? (f) Why must the starting line containing the drops of food dye solution be placed above the solvent level at the beginning of the experiment? (g) State the steps taken to ensure effective separation.

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Topic: Magnetic Fields

Purpose: To study the behavior of a bar magnet in varying magnetic fields at the end of a solenoid and hence estimate the horizontal component BH of the Earth's magnetic fields.

Theory: If a magnet is suspended from a thread, it always ends up pointing in the same direction. One end points nearly to the North, the other to the South. The pole at the end pointing North is called the north seeking pole or N pole. The pole at the end pointing South is called the south seeking pole or S pole.Magnetic field is the region around amagnet where any other magnet or magnetic material coming into this field will experience a force.A solenoid is a special term for a long coil made up of several turns of wire of the same diameter. The magnetic field of each coil add up to give a strong field along the centre line(the axis) of the solenoid. The magnetic field of a solenoid is very similar to the field around a bar magnet The coil behaves as if it has a N pole at one end and a S pole at the other end.

Apparatus:

(i) A retort stand and two clamps (ii) A cork and an optical pin(iii) A set of small bar magnet fixed with a pair of optical pins (iv) A plane mirror attached to a protractor(v) Thread of length about 40 cm(vi) A test-tube wound with copper wires(vii) A 2 V accumulator or any other stable power supply(viii) A (0 – 1)A dc ammeter(ix) An on - off switch and three connecting wires (x) A rheostat(xi) A pair of vernier calipers(xii) A micrometer screw gauge

Procedure:

(a) Clamp the cork with a pin to the retort stand and hang the bar magnet from the pin using the thread supplied, so that the magnet stays at a height of about 5 cm above the table. Keep all magnetic materials away including the ammeter. Allow the magnet to stay stationary. Place the mirror with the protractor directly below the magnet and the 0° - 180° axis parallel to the pins on the magnet.

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(b) Using the other clamp, hold the solenoid in a horizontal position at the same level with the magnet. Adjust the orientation of the solenoid so that its axis is perpendicular to the axis of the magnet and one end of the solenoid is at 3.0 cm from the axis of the magnet. Connect a rheostat, ammeter, power supply and switch to the solenoid in series. The ammeter should be kept at least 50 cm from the magnet. The arrangement of apparatus should look as in Figure 10a.

Figure 10a

(c) Adjust the rheostat to maximum resistance and close the switch. Record the reading I of the ammeter and obtain the average deflection of the magnet from the 0 0 - 180 0 axis. Decrease the value of the resistance of the rheostat in stages so as to change the value of I and then measure the corresponding value of . Record all measurements for , , and tan .(d) Plot a graph of tan against .(e) At the point where = 0.20 A, find the gradient s of the graph of tan against .(f) Remove the solenoid and measure (i) the internal diameter D of the solenoid, (ii) average diameter d of the wire used in the solenoid, (ii i) length L of the solenoid.(g) Use the values of d and L to estimate the number of turns N in the solenoid.

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(h) Calculate the value of the horizontal component BH of the Earth's magnetic field using the following estimation

BH 1 -

where = 4 x 10-7 Hm-1 and = 0.030 m.

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03_ prac sc1 & sc 2

Documents

micrometer

wash bottle

triple beam

tutorials

empty measuring

varying magnetic

methylene

ventral surface