Notes for Labs
One of the most important phases of experimental work is the presentation of findings in an intelligible and convincing form. To conserve the student's time, I require that the report be elaborate enough merely to be understandable and convincing to one already acquainted with the general nature of the experiment.
Your lab report is to be based solely on data obtained experimentally by you and your partner while in the lab. Obtaining data consists, essentially, of reading numerical quantities from equipment when it is in predetermined conditions of adjustment and operation. Such readings must never first be jotted done on scratch paper and then be recopied; they must always be recorded directly on data sheets and become part of the report. If any number read directly from equipment is worth written down anywhere in the lab, it must be put directly on a sheet to be kept permanently. If you make a mistake, draw a line through it and write the other number next to it.
Original data must not be confused with calculated results. For example, original data on the number of revolutions made by a motor during a certain run consist of the readings of the revolution counter connected to the motor immediately before and immediately after the run. The difference of the two readings, which is the total number of revolutions made during the run, is not a piece of original data but is a calculated result. Original data can be replaced only by performing the experiment again; calculated results can be reproduced merely by calculation from the original data. Unlike data, calculations may be carried out initially on scratch paper before they are entered in the permanent report. A well-organized data sheet is often a great aid in locating and correcting an error made while taking data.
I will provide data sheets for your use. Do not reproduce these sheets.
It is usually perferable not to include other phases of the report on the sheet carrying original data. Where advantageous, however, some calculations may be included on the page with the original data. For instance, averaging of data may be done or intermediate calculated results may appear in columns of the table succeeding the data. Each individual will make his own calculations from the data obtained in partnership.The calculations should be presented neatly in the space provided on the report forms, in sufficient detail that they may be checked readily with a calculator. When more than one calculation using the same equation is made, the results may be listed in a table, acccompanied by only a single sample calculation worked out in detail. Care must be exercised to carry outt all steps of the calculation to a suffient number of significant figures so as to not jeopardize the results.
If a graph is to appear in the experiment, it is to be plotted on a separate sheet of finely divided graph paper. A title for the graph must appear on the sheet. The independent variable is to be plotted as the abscissa or horizontally, the dependent variable as the ordinate, or vertically. Units are to be chosen in such a way that the graph will occupy a symmetrical spacing on the sheet and the units clearly indicated. A smooth curve is to be drawn averaging the points on the graph, unless specific instruction is given to the contrary. Graphs should always be drawn in pencil. Whenever a slope is to be computed from a graph, it should be done in a corner of the graph that does not interfere with the curve or the data points. Graph paper will be provided for your use.
The questions at the end of the experiment have been designed to test your knowledge of the experiment. Often they will be worded in a manner that requires you to make a conclusion from your results or to discuss and compare your results in some way. When answering these questions, do so in complete sentences and utilize the physical concepts and formulas you have learned. Be precise and specific, avoid broad and vague anwers that say nothing. You are, at this point, demonstrating what you have learned during the course of the experiment and that you have not wasted your time.
I will inform you of the schedule for the experiments. Therefore, you will know in advancewhat experiment will be done in the next lab session ALWAYS STUDY THE EXPERIMENT BEFORE COMING TO THE LAB. Not just because you will be quizzed on it, but mainly because if you do not, you will have a difficult time understanding what you are supposed to do during the session. You will also have difficulty completing the lab in the alloted time.