Vernier Caliper Experiment

To know the use of the Vernier Calipers


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To know the use of the Vernier Calipers

To know the use of the Vernier Calipers

Our Objective 

  • To know the use of the Vernier Calipers.
  • To measure the diameter of a small spherical / cylindrical body.
  • To measure the length, width and height of the given rectangular block.
  • To measure the internal diameter and depth of a given beaker/calorimeter and hence find its volume.

The Theory 

What is a Vernier Caliper?

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.

Parts of a Vernier Caliper

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.

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;

or

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 Caliper;

If the zero of the vernier scale lies ahead of the Nth division of the main scale, then the main scale reading (MSR) is;

 

If nth division of Vernier scale coincides with any division of the main scale, then the Vernier scale reading (VSR) is;

 

Total reading,

Finding the Volumes

Volume of a Beaker / Calorimeter

Volume of the beaker / calorimeter = internal area of the cross section x depth

This can be expressed as;

where ‘D’ is the internal diameter of beaker / calorimeter and ‘d’ the depth of beaker / calorimeter.

Volume of a Sphere

where ‘r’ is the radius of the sphere.

Volume of a Rectangular Block

where ‘l’ is length of the block, ‘b’ the breadth and ‘h’ the height of the block.

Learning Outcomes

  • Students get to know the use of vernier calipers.

Students know what is the Least count of vernier callipers

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Experiment

Materials Required 

  • Vernier callipers.
  • A spherical body ( it can be a pendulum bob)
  • A cylinder.
  • A small rectangular metallic block of known mass
  • A beaker or a calorimeter.

The Procedure

  1. We'll first determine the vernier constant (VC), which is the least count (L.C) of the vernier calliper and record it stepwise as in the equation, L.C = 1 MSD - 1 VSD.
  2. Now, bring the movable jaw in close contact with the fixed jaw and find the zero error. Do this three times and record the values. If there is no zero error, then record 'zero error nil'.
  3. Open the jaws of the Vernier Calliper and place the sphere or cylinder between the two jaws and adjust the movable jaw, such that it gently grips the body without any undue pressure on it. That done, tighten the screw attached to the Vernier scale.
  4. Note the position of the zero mark of the Vernier scale on the main scale. Record the main scale reading just before the zero mark of the vernier scale. This reading (N) is called main scale reading (MSR).
  5. Note the number (n) of the Vernier scale division which coincides with the division of the main scale.
  6. You'll have to repeat steps 5 and 6 after rotating the body by 90o for measuring the diameter in a perpendicular direction.
  7. Repeat steps 4 to 7 for three different positions and record the observations.
  8. Now find total reading using the equation, TR = MSR+VSR = N+(n x L.C)  and apply the zero correction.
  9. Take the mean of the different values of the diameter and show that in the result with the proper unit.
Note:
  • To measure the internal diameter of a calorimeter or beaker, place the beaker upside down over the internal jaws of the vernier calipers.Then repeat the steps 4 to 8.
  • To find the ‘Depth’ of the beaker, move the metallic strip till it touches the bottom of the beaker.Then repeat steps 4 to 8.

 Procedure

  1. Select the object to measure by clicking on it.
  2. The object is placed between the jaws of the vernier caliper.
  3. Drag the movable jaw so that it touches the object.
  4. Based on the object selected, select the physical dimension to be measured.
  5. Note the MSR and VSR value that exactly coincides with the main scale.
  6. Calculate the dimension using the equation 2.
  7. Enter the reading in the ‘Enter Reading’ text box.
  8. Click on the ‘Check’ button to find if the reading entered is correct.
  9. If the object selected is the ‘Beaker’;
    • To find ‘Internal Diameter’ drag the mouse to move the jaw of the vernier scale away from the jaw of the main scale till the jaw  touches the opposite inner wall of the beaker.
    • To find the ‘Depth’ of the beaker, drag the jaw of the vernier scale away from the jaw of the main scale till the metallic strip touches the bottom of the beaker.
    • Enter the reading in the ‘Enter Reading’ text box.
    • Click on the ‘Check’ button to find if the reading entered is correct.
  10. Click on the 'Reset' button to reset and perform the experiment once again.

Our Observations 

  1. Determination of Vernier constant (Least Count ) of the vernier callipers: 1 M.S.D. = 1 mm 10 V.S.D.= 9 M.S.D. 1 V.S.D.= 9/10 M.S.D. = 0.9 mm. Vernier Constant, V.C.= 1 M.S.D.-1 V.S.D. = (1-0.9) mm = 0.1 mm = 0.01cm.
  2. Zero error (i).........cm, (ii).........cm, (iii)...........cm. Mean zero error (e)=..........cm. Mean zero correction (c) = -e=.........cm.
Dimension to be measured Sl No Main Scale Reading MSR cm Vernier Scale Reading VSR cm VSR x L.C cm Toatl Reading MSR + (V S R x L.C) cm Mean cm  
Diameter of the bob            
           
           
Diameter of the cylinder            
           
           
Length of thye cylinder            
           
           
Length of the block            
           
Breadth of the block            
           
Thickness of the block            
           
Internal diameter of the beaker            
           
Internal depth of the beaker            
           

Calculations 

Mean corrected diameter------------cm Volume of sphere,=---------cm3= ------m3. Mean corrected length of the block, l=............cm Mean corrected breadth of the block,  b= .......cm Mean corrected thickness of the block,  h= .........cm Volume of block ,  =........................cm=..........m3 Density of the block material,=..................cm Mean corrected internal diameter,D=................cm Mean correcteddepth,d=........cm Volume of beaker / calorimeter ,= ..........cm3=............m3.

The Result

The volume of the beaker / calorimeter is ...........m3. Volume of Sphere=.......................... m3 Volume of block is ................................m3 The volume of the  beaker / calorimeter is ...........cm3.