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Friday, May 22, 2026

Vernier calliper for std 8 to 12 GSEB Students, & ITI fitter measuring instruments.

Vernier calliper measuring instrument for ITI fitter and Gseb students.

Vernier calliper

A calliper is a device used to measure the distance between two opposing sides of an object. It can be as simple as a compass with inward or outward-facing points. First the tips of the calliper are adjusted to fit across the points to be measured and the calliper is then removed and the distance between the tips is measured using a ruler.

The modern Vernier calliper was invented by Joseph R. Brown in 1851. It was the first practical tool for exact measurements that could be sold at an affordable price to ordinary machinists. The Vernier Calliper consists of a main scale fitted with a jaw at one end. Another jaw, containing the vernier scale, moves over the main scale. When the two jaws are in contact, the zero of the main scale and the zero of the Vernier scale should coincide. If both the zeros do not coincide, there will be a positive or negative zero error.

1.Main Scale
The main scale consists of a steel metallic strip graduated in centimeters at one edge and in inches at the other edge . It carries the inner and outer measuring jaws. When the two jaws are in contact, the zero of the main scale and the zero of the Vernier scale should coincide. If both the zeros do not coincide, there will be a positive or negative zero error.

Vernier calliper

Least count of Vernier

Vernier calliper Main Scale

Vernier calliper

Vernier calliper calculation

Vernier Calliper

vernier calliper least count

vernier calliper least count and Table

vernier calliper Measuring rectangle

2. Vernier Scale
A vernier scale slides on the strip. It can be fixed in any position by the retainer. On the Vernier scale, 0.9 cm is divided into ten equal parts.

3. Outer Measuring Jaws
The outer measuring jaws helps to take the outer dimension of an object

4. Inner Measuring Jaws
The inner measuring jaws helps to take the inner dimension of an object.

5. Retainer
The retainer helps to retain the object within the jaws of the Vernier calipers.

6. Depth Measuring Prong
The depth measuring prong helps to measure the depth of an object.

Least Count

The least count or the smallest reading which you can get with the instrument can be calculated as;

First calculate the least count and only then place the object between the two jaws.

Record the position of zero of the Vernier scale on the main scale.
Calculating the Reading

When a body is between the jaws of the Vernier Calliper.

More details view video:

Vernier calliper video Measuring rectangle practical.

pH value of solution and fruit juices GSEB std 8 to 12 Science

ph Value of Fruit juice

To determine the pH value of solution and fruit juices with the use of pH-paper approximately.

AIM : To determine the pH value of solution and fruit juices with the use of pH-paper approximately

APPARATUS : Seven glass test tubes, one dropper, Test tube stand, and glass rod. Dilute hydrochloric acid solution,Lemon juice, Tomato juice, Distilled water, Sodium chloride solution, Sodium hydroxide solution, Sodium carbonate solution,

THEORY : [ The pH scale runs from 0 to 14 ]

If the pH of a solution is 7 it is a neutral solution. pH of acid is less then seven and that of base is more than seven.

Thus the nature of solution whether neutral, acidic or basic can be known by knowing by pH value of solution. In the school laboratory pH value is determined by using pH papers. The basic principle of the pH paper is that it undergoes a suitable change in colour which is characteristic of the pH of the test sample of the solution. In this way pH paper is an indicator in different media of solutions giving different colour.

In the laboratory red and blue litmus papers are also used to find pH value less than 7 pH, more than7pH and 7pH.

pH value of solution and fruit juices

ph value of Dilute hydrochloric acid

pH value of solution and fruit juices

ph vales of Sodium chloride solution

ph vales of different Fruit juice

ph values table

CONCLUSION

PRACTICAL USES : From pH value the property of substance or solution whether acidic, neutral or basic can be determined.

Influence of Heat (temperature) and Chemicals on the Pigments from Root and Tissues of Plant. std 11 & 12 biology

Study the Influence of Heat (temperature) and Chemicals on the Release of Pigments from Root and other Tissues of Plant

Influence of heat on Beat root

AIM :-

To study the influence of heat (temperature) and chemicals on the release of pigments from root and other tissues of plant.

INSTRUMENTS AND MATERIALS

Test tubes, cork borer, blade, beakers, measuring cylinder, thermometer, burner,

Fresh beet roots, alcohol, formalin, benzene, distilled water, ice cubes.

Observation :-

Table 1 : Effect of temperature on leaching of pigments from the beet root.

Conclusion

Betacyabin is present in the cell sap of beet root in vacuoles when beet root is kept at high temperature the permeability of cell membrane is effected. High temperature damages the membrane and pigment leaks out from the membrane. This leaking is maximum at high temperature.

Observation :-

Table 2 : Effect of various chemicals on the permeability on the cell membrane.

Conclusion:

The organic solvents like formalin and alcohol damage the cell membrane by dissolving fat and denaturing proteins. This permeability of cell membrane increases. So more leaking of pigment takes place.

More details view video:

Study the Influence of Heat (temperature) and Chemicals on the Release of Pigments from Root and other Tissues of Plant

Monday, April 7, 2025

Study of Osmosis by Potato Osmometer, Biology practical std 11 & 12

Study of Osmosis by Potato Osmometer,

Potato Osmosis practical

Study of Osmosis by Potato Osmometer

AIM :- To study osmosis by potato osmometer.

INSTRUMENTS AND MATERIALS Petridish, scalpel, pins, Potatoes, sugar, water, eosine (stain).

Conclusion :-

(A) When Potato bath is placed in Hypotonic solution due to osmosis the water flows from petridish containing hypotonic solution to the hypertonic solution in the potato bath and water level increases.

(B) When potato bath is placed in hypertonic solution due to osmosis the water flows from potato bath containing hypotonic solution to the hypertonic solution in petridish and water level decreases.

To prepare ammonia gas in the laboratory and study its properties GSEB std 8 to 12

Prepare Ammonia Gas

To prepare ammonia gas in the laboratory

AIM : To prepare ammonia gas in the laboratory and study its properties

THEORY : On heating a mixture of ammonium chloride and calcium hydroxide, we get ammonium gas.

APPARATUS : Big hard glass tube, delivery tube, hollow glass tube, Bunsen burner, glass rod, two single-holed rubber cork, four to five gas jar with lids, stand and one CaO bottle as shown in the figure.

CHEMICALS : Calcium hydroxide, ammonium chloride, concentrated hydrochloric acid, red and blue litmus papers.

Preparation of Ammonia gas

Prepare Ammonia Gas In Laboratory (step-1)

Prepare Ammonia Gas In Laboratory (step-2)

Prepare Ammonia Gas In Laboratory (step-3)

Prepare Ammonia Gas In Laboratory (step-4)

Prepare Ammonia Gas In Laboratory (step-5)

Prepare Ammonia Gas In Laboratory (step-6)

Observation :

i. Colour of ammonia gas :

ii. Odour or smell of ammonia gas :

iii. Ammonia gas is collected by downhard displacement of air therefore it is than air.

iv. Use moist red and blue litmus papers and check the effect on ammonia gas and conclude :

Wet red litmus :

Wet blue litmus :

Conclusion :

What happens when a glass rod is dipped in concentrated HCL is brought near the mouth of gas jar containing ammonia ?

CONCLUSION

PRACTICAL USES

Ammonia is used in the manufacture of fertilizers, nitric acid, nylon fibers and in many organic chemicals.

To prepare Soap by cold process. Science practical GSEB for std 8 to 12.

Soap making practical

Soap making with Cold Process.

AIM : To prepare soap by cold process.

THEORY : Sodium hydroxide and vegetable oil reacts to give soap and the process is called saponification.

APPARATUS : Beaker, glass-rod, bunsen burner, mould, wire gauze, Sodium hydroxide, vegetable oil, Soap, Sodium hydroxide, vegetable oil, Salt,

CHEMICALS : Sodium hydroxide, vegetable oil (castor oil) and salt.

Soap making with cold process

Observation :

Conclusion :

Uses : Soap is used to remove dirt from the surface of clothes.

For more details view Video :

Soap making with Cold Process.

MEASUREMENT OF RESISTANCE ( WHEATSTONE’S BRIDGE) gseb std 11 & 12 physics practical.

Wheatstone's bridge

MEASUREMENT OF RESISTANCE

( WHEATSTONE’S BRIDGE)

Condition (1) :- MEASUREMENT OF RESISTANCE

AIM :-

You are given a Wheatstone bridge and other necessary instruments. Find the values of the unknown resistance Rx. Exchange the positions of unknown resistance and resistance box in the gaps of Wheatstone bridge and repeat the experiment.

PRINCIPLE :-

It works on the principle of balanced Wheatstone bridge.

Apparatus :-

Wheatstone-bridge (meter-bridge),

2 Volt Battery,

Rheostat,

Galvanometer,

Jockey,

Key,

Resistance box(1 – 100 W),

Resistance coil.

Precautions

Make proper and tight connections.
Keep the keys tightly closed in the resistance box.
Adjust the value of resistance box so that null point is obtained between 40 cm and 60 cm.
Do not slide the jokey continuously over the wire.

Note :- Keep high resistance of rheostat in the beginning of each observation so that current is less and the galvanometer is not damaged. After getting approximate position of null point only decrease the resistance of rheostat.