(40) Reyes, Christine(41) Reyes, Kristina Barbara(42) Rivera, Grace Anne Francel(43) Samonte, Ana Carmela (44) Santos, Romilda(45) Soliven, Rianne2CMT, Faculty of Pharmacy, UST

The Vernier Caliper and MicrometerExperiment # 1

Abstract:The objective of the experiment is to learn how to measure the dimensions of

objects accurately by means of the Vernier Caliper or Micrometer. The Vernier Caliper is a scale with an accuracy of 0.05 mm. and can measure up to 155.0 mm. while the Micrometer is a scale with an accuracy of 0.01 mm. and can measure up to 25.00 mm. Each group is provided with a steel washer, glass marble and a copper/steel/aluminum cube. They are to measure each of the solids’ mass using the triple beam balance, compute for the volume given the varying formulas assigned for each type of solid (i.e., Vcube = s3) and compute for the density using

the direct measurement of mass and the computed volume ( ). The standard

and experimental densities were compared and the percentage error is computed (

. The demand of the experiment is to exhibit mathematical and logical

skills by ensuring accurate computations and applying strict rules on significant figures.

Guide Questions:1. Differentiate the Vernier and Micrometer Scales.

Both the Vernier and Micrometer Scales are used in measurements of the dimensions of objects; however, they differ in terms of capacity and accuracy. A Vernier Caliper can measure a solid object up to 155.0 mm in length and has an accuracy of up to 0.05 mm. Its main scale is marked in divisions of 0.1 cm while its vernier scale is marked in divisions of 0.01 cm. A Micrometer on the other hand can measure only up to 25.00 mm but has an accuracy of up to 0.01mm. Its main scale is marked in divisions of 0.5 mm while the vernier scale is marked in divisions of 0.01 mm.

2. Draw the figure for the micrometer readings below:

a. 3.68 mm

0 25

20

15

10

b. 1.59 mm

3. State some of the errors that one might make in measuring length using both the Vernier and Micrometer Calipers.

Making use of measuring devices such as the Vernier Caliper and the Micrometer could really contrive disparities among the obtained measurements. There are various sources of errors when using laboratory instruments in general. Among others are systematic errors and random errors. Systematic errors includes external errors brought about by change in temperature, wind, unexpected movement, etc; instrument error caused by uncalibrated and faulty apparatus; and personal errors where the person measures the object with a degree of bias. Random errors include parallax error where a person measures the solid objects inaccurately due to incorrect positioning of the eye.

Particularly, the most common source of error in Vernier Calipers and Micrometers is “Zero Error.” When the jaws are closed, the vernier zero mark must coincide with the zero mark on its fixed main scale. If not, one must note the reading. This reading is called “zero error”. The zero error is of two types: the positive zero error and the negative zero error. Positive zero error occurs when the zero on the vernier scale is to the right of the main scale. Therefore, the zero correction should be subtracted from the reading which is measured. On the other hand, Negative zero error occurs when the zero on the vernier scale is to the left of the main scale; thus, the zero correction should be added from the reading which is measured.

4. Determine the percentage error for an observed value of 1.112x10-5 if the standard value is 1.117x10-5.

% error =

% error =

% error =

% error = 0.4476%

0

15

10

5

0