MHS Chemistry
How To Write A Lab Report
Mr. Zahm

Grades & Rubrics
This document is a guide to help you write a lab report to pass in.  There are two other pages of which you should keep track:  there is a General Lab Rubric, which is a description of what you should include for a "4" or a "3" etc; and for most labs there is also a "score sheet."  The scoring sheet is specific for each lab.

At present, our school grades on an A-B-C-D-F scale, with hints of a 1-2-3-4 "Standards" system to come.  For now, I will grade each of the sections listed below on a 1-4 scale (4 is best); the lab grade will be the percentage of possible points earned.  Since each lab report will have a different combination of these sections, each lab will have a different number of possible points to earn.  This policy will change if/when MHS reports on a 1-4 absolute scale instead of the usual A-F.

For more specific details about grading in your class, see your own Room Management Plan [Chemistry][AP Chemistry].

Lab Reports
A Lab Report should be a document that tells the reader what was done in an experiment or activity, and what was discovered.  It should be written so that the reader can duplicate the activity and results if they so desire.  Some labs will be performed from handouts or lab manuals, while in others you will devise your own procedure.  This is supposed to be a general guide so you can write a clear lab report from any class activity in any science class.  Remember that the main goal is to show the reader what was done in the order it was done.  Some of the details will be different from teacher to teacher, so make sure you ask and take notes!

  1. Title Section - This should be the first thing the reader sees when they look at your report.  It should include your name, the name of anyone you actually worked with (write "no partner" if you worked alone), the date the lab is due, the class and period, and of course the title of the lab.  Some teachers may want you to include their name too, so make sure you ask.  If there is a handout for the lab, it may include most of this information already, so you may not need to make a separate section or page.  If the teacher does not limit the number of pages to turn in, a separate title page is always good.
  2. Purpose/Hypothesis - This section should be short, and should tell the reader why the experiment was performed.  Do not describe the procedure or repeat the introduction section of any handouts - this section should be short!  This section may actually be unnecessary if it is included on the lab handout, and you are allowed to include the handout.

  3.         Activities that are designed to prove a point, determine a value, or identify an unknown will have a stated purpose.  It should be short: one or two sentences stating the goal of the activity.
            Activities designed to answer a question should have a hypothesis.  This is an "If...Then..." statement that can be proven or disproven.  For example:  "If the balloons are filled with oxygen, then they will cause a glowing match to reignite."
            Did I mention this section should be short?
  4. Procedure - A concise numbered list of instructions describing what you actually did - not what you meant to do.  If this is on your lab handout you may not need to re-write it, but you should note any changes you made.  Also, if you performed a procedure from a lab manual, don't re-write the steps, just tell the reader exactly where they can find the procedure.
  5. Data & Observations - Data is any information you read directly off a tool or instrument (like temperature, but not like change in temperature).  This should always be in table form.  Make sure every single number has a description, a value, and a label (this can be condensed if you have many similar pieces of data by labeling a column heading such as "Length (m)").  Make sure you read your instruments correctly.  There should not be any information that isn't data, and there shouldn't be anything missing.  Data should be presented in the order it was obtained.  Spend time making sure this section is clear and easy to read.  For additional hints check out the document "How To Record And Present Data."
  6. Graph(s) - Sometimes it is easier to show information or perform calculations on a graph than a list of numbers.  In some cases, a graph will be shown but not the data it came from (keep the data in your notebook!).  A graph should always fill the available space.  The axes should be named and labeled ("Mass in grams").  The scales should be consistent but they don't have to be the same (you can count by 5's on the y-axis as long as you count by 5's on the whole y-axis, and you can count by 2's on the x-axis as long as you count by 2's on the whole x-axis).  You only need to use a range to include your data - if the temperature stays between 20 and 70 Centigrade, your graph doesn't need to go from 0 to 100.  There are more hints in the document How To Make A Good Graph, but a good general hint is that you should use as little ink as possible but still cover the page.  For extensive further information find the book "The Visual Display of Quantitative Information" by Edward R. Tufte (Graphics Press, CT; or
  7. Analysis or Questions - this part depends on the lab.  You may have specific questions to answer or calculations to perform.  Most handouts or lab manuals include a few questions or instructions after the procedure.  Show these clearly and fully answered in the order they turn up.  Show all your work for calculations (including names and labels; see below) and answer every question with full sentences and clear explanations.  Here are two sample calculations (one addition, one multiplication):
      mass of beaker with water
    -  mass of beaker
    - 166.202
    = mass of water
    = 105.243
    heat transferred
    q = mDtCp
    q = (42.101 g)(5.5 C)(1cal/gC)
    q = 230 cal
  9. Your lab should be Neat - The sections must be in the correct order, one side of each sheet, stapled in the top left corner, typed (or neatly written in dark ink), few or no cross outs, no notebook "snow," and good general presentation.
  10. Your lab should also be Prompt.  There will be a one point penalty for each day the lab report is late.
And finally, every lab has several dates attached to it: the day we did it in class, the day it is due, the day the re-writes are due (usually the Friday after I pass it back to you), and the day I officially "lose interest" and will not accept the lab (usually the Friday after the re-writes are due).  It is up to you to pay attention in class to know when these dates are coming.

For the first several labs of the year you will be given a specific point-by-point scoring guide describing what should be passed in, but after that you will be expected to extract this information from the lab handouts or your experience in the classroom.  I will still use them to correct every lab, but you will only see them for the re-writes.  If you ever have any questions, first check with your partner, then refer to your lab handout, then finally ask me.

[General Purpose Lab Rubric][MHS Chem page][MHS AP Chem page]