Medidas

EXPERIMENT #1

A. DETERMINATION OF LENGTH, MASS AND DENSITY
B. MEASUREMENTS, MEASUREMENT ERRORS, AND GRAPHICAL ANALYSIS

FISI 3013 SECTION ________

DATE OF EXPERIMENT: _______________

DATE DUE: _______________

DATE HANDED IN: _______________

COORDINATOR: ______________________________

GROUP MEMBERS:

______________________________

____________________________________________________________

Prepared and revised by: Prof. Haydee Pérez-Kraft
June 2008
A. DETERMINATION OF LENGTH, MASS AND DENSITY
B. MEASUREMENTS, MEASUREMENT ERRORS, AND GRAPHICAL ANALYSIS

APPARATUS: Laboratory balance, meter stick, vernier caliper, micrometer caliper, metal cylinder, copper wire (90-100 cm), set of masses, irregular solid, a 250 ml graduated cylinder, lightweightstring, small sphere, six circular disks having different diameters

THE PURPOSE OF THIS EXPERIMENT:
(A) is to acquaint the student with length and mass measuring devices; to help the student learn the basics of measurement and measurement error;
(B) to learn measurement techniques, analysis of measurement errors, and graphical analysis.

THE METHODOLOGY OF THIS EXPERIMENT:
(A) will be to makemeasurements with rulers, vernier calipers, micrometer calipers, and laboratory balances, on various objects. The results will be evaluated in terms of measurement errors.
(B) uses several measurement techniques to determine the circumference and diameter of circular disks. This data will be used to compute π. Since this value is well known the student can determine the precision of theirmeasurements.

PROCEDURE
A.
5. Now measure the diameter and length of the cylinder with the vernier caliper, about three trials for each; then estimate the uncertainty of measurement for each. Record the averages in the form m ± d, and compute the percent uncertainty in the measurement of each dimension of the cylinder.

6. Measure the diameter of a copper wire with the micrometer caliper, andmeasure the length with a meter stick. Record both dimensions in centimeters, Why?

7. Place the small sphere between the end of the cylinder and the edge of your lab book, and measure its diameter in centimeters with a meter stick. Make three trials, using different reference points, and record on your data form in the column for length. Now make three trials of the diameter measurement using themicrometer caliper and record. Then record the average for each set with the uncertainty indicated.

8. Determine the masses of the cylinder, the wire, and the sphere by weighting on the laboratory balance. Compute the volume and the density of each. The volume of a cylinder is given by
V = π r² h, and that of a sphere by V = π d³ / 6.

9. Determine the mass of an irregular solid, weighing iton the laboratory balance. The volume can be determined by the water displacement method. Partially fill the graduated cylinder with water to some easily read level. By means of a lightweight string, lower the irregular solid into the water until completely submerged; then carefully read the new water level. Record the volume of the solid as that of the displaced water. Then compute the densityand compare with the value listed in Appendix B (Table 1).

B.
1. Study the equipment supplied and try to decide on a method of making the required measurements. If it seems that other equipment is needed, or would be better, perhaps the instructor can furnish the items you need. For the first method chosen, however, it is requested that all the circular disks be measured by the same method.2. Measure the circumference and diameter of each disk, listing them in order of size, beginning with the smallest. Record these measurements along with the kind of material of each disk. In recording the data, follow the suggestions in Section II of the INTRODUCTION of this manual – dealing with significant figures.

3. Compute the value of π, from the relation π = C/D, for each set of...