Regents Physics Lab Writeup Manual

 

Introduction:

There are three types of lab writeups: activities, packet labs, and formal labs. This manual provides guidelines for writing your lab reports. While all lab reports should, at minimum, follow this manual, you may be asked to include items not listed here. Finally, remember to put all graded labs into your lab folder.

 

Packet Labs:

Packets are provided to you and must be filled out neatly and thoroughly. If you need to graph in a packet lab, see the section on formal labs for graphing rules.

 

Activities:

Follow the following writeup format for lab activities. They may be handwritten, but must be neat!

 

Formal Labs:

A formal lab report is a complete and accurate record of your laboratory exercise.  It should be written in such a manner that a person unfamiliar with the exercise gains a clear understanding of the entire process by reading your report.

Formal lab reports take a significant amount of work to complete. It is expected that they demonstrate your best work. As such, this section of the manual is rather extensive. Be sure to read all of the information provided here. While you may have written formal lab reports for other classes, do not assume that your physics labs will not be any different. The rules for graphing are particularly important to review.

General Guidlines

Formal Writeup Checklist

Make sure that you have included the necessary sections from the following list in your formal lab writeup. They may not all be needed for every lab report. Use your best judgement and ask your teacher when in doubt.

Purpose

This section of the lab report explains why an experiment is being performed.  It may be to observe a process, to investigate a problem, or to answer a question.  It is possible but not probable that a lab may have more than one purpose.  This section may be a sentence but should be no more than a single paragraph.

Hypothesis

A hypothesis is a possible solution to a problem or an answer to a question.  In the hypothesis you predict what you believe will solve the problem or what the answer will be.  Your predictions and estimations should be based on knowledge or research, not just a guess.  Some experiments are just investigations and may not have a hypothesis.

Background

This section requires that you explain what it is that you are doing. It should be an explanation of why you are doing the lab and why you are doing the lab the way that you are.  You should include the ideas that generated the purpose, the formulas used in the lab and the reasons behind the use of those formulas, any experiments that may have led to this lab, any special history involved with the lab, etc.

Procedure

If the procedure is given to you printed in detail, include it.  You generally will not be allowed to have with you any prelab sheets that have been handed out to you. If no directions are given, your procedure must be very specific and should answer the question "How will you perform the experiment?"  It should include all steps (numbered if possible) in the order in which they will be performed.  You should include any safety precautions in this section as a separate paragraph.

Diagrams

Many labs will require that you construct a diagram of the apparatus or to make diagrams for your observations. You may draw diagrams by hand if you wish, but you must do so neatly. Because drawing diagrams is difficult, they should be done in pencil to allow for ease of modification.

Data

Data is the information you collect while performing the experiment.  It may be a set of numerical measurements such as temperatures, times, distances, and masses or it could be a set of observations taken such as color changes, comparisons with a standard, and so on.  BE SURE TO INCLUDE UNITS AS NECESSARY! Data makes more sense if it is presented in chart, tabular, or graphic form.

Rules to follow:

  1. Include ANY AND ALL data obtained during the lab.  You may need it later.
  2. Include units with all numbers.  Numbers without units are meaningless.
  3. Be sure to have an identification name for any data.  The identification name must be more that a symbol.  Numbers without any identification are useless.

Analysis

Many times you will be applying the same formula to each of your data points. If this happens you should make an ANALYSIS TABLE to show your results. Since you probably will be using a calculator there is no sense in having you write the same equation many times. However, it is important that you show that you are using any equations properly. Equations that are used to manipulate data must be shown. The formula should be written in its symbolic form, the numbers with their units should be substituted in the proper place, and the answer indicated with the proper units. If the equation is used many times, use data from the middle (not the first or last) in your representative calculation. Percentage difference from an accepted value is always positive. Be sure to show any calculation for percentage difference. It is not necessary to show how you arrived at averages.

Graphs

The following rules pertain to constructing graphs:

  1. All graphs must be done on a sprebadsheet.
  2. The graph must have a title at the top. It should be in the format: Dependent Variable (y-axis) as a function of Independent Variable (x-axis).
  3. Choose your axes so that relevant information is displayed on as much of the graph area as possible.
  4. Often, you will be asked to draw a best-fit curve or a best-fit line. Rules for these are listed in the next section.

Best-fit Lines and Best-fit Curves

The following rules pertain to constructing best-fit lines and curves:

  1. Best-fits should always be smooth. This means that you should never connect the dots.
  2. Best-fits should best fit all of the data points. This means that the same number of data points should lie above as below the best-fit. A best-fit does not have to go through any data points.
  3. Best fits do not have to go through the first and last data points.
  4. Best fits do not have to go through (0,0).
  5. Most often, but not always, your best-fits will be straight lines. In these cases you will be asked to find the slope of the line. Be sure to use points on the line and not data points to find the slope! Slope is given by the formula m=(y2-y1)/(x2-x1). Do not forget to include units in your slope!

Results

Results are written to answer the purpose. If you read your purpose, you should be able to determine what to include in your results. Your results must be written in complete sentences. Your results should summarize any analysis you have done and should also include your uncertainty analysis.

Uncertainty Analysis

This is an analysis of ways that the data may have been uncertain and how much this uncertainty may have been. It should include:

  1. What specific steps in the procedure could have affected the quality of the data and why.
  2. How might the equipment interfered with the collection of accurate data and why.
  3. Problems you discovered during the course of the experiment and how you corrected for them.
  4. The percentage difference found in your calculation section. Percentage difference only tells you how close you came to an expected answer. It does not tell you how good your data was.
  5. Indicate the uncertainty of your data (either here or on your data) and the uncertainty of your answer if you have been able to find it. Uncertainty is different from percentage difference and should not be confused. Uncertainty tells you how good your data is and will help to tell you how good your results are.

Conclusions

The conclusion answers the hypothesis and examines the procedure followed. You may still have a conclusion even if you do not have a hypothesis. Your conclusion should be at least two sentences long and include the following:

1. General Statement. State whether your hypothesis was accurate or whether your purpose for performing the lab has been achieved.

A. If a hypothesis is being tested the general statement should state whether the data you collected supports or rejects the hypothesis.

B. If no hypothesis is being tested the general statement should tell if you accomplished the purpose of the lab.

2. Specific Statement. This is the proof for your conclusion. If a graph has been drawn, the type of relationship between the variables should be stated (linear, direct, inverse, etc.). If an analysis with results was found, a sentence that indicates which results will support the general statement (#1) should be included.