Lab Report

How to Write a Lab Report

A lab report is a document that explains the observations and conclusions drawn based on an experiment.  The Lab Report is written in the third person objective passive voice and contains a reasonable analysis of errors.  The point is to convey objective data. The third person subject is implied. No “You”, No “the researcher”, No people. This exercise will walk you through the parts of the lab report and what is expected throughout the course.

 

Title: Caffeine from Home Brewed Coffee – Drip vs French Press

One sentence or fragment describing the experiment.

 

Abstract:

This is where the thesis statement will be presented. The abstract is basically the TL;DR version of the lab. The abstract should contain:

  1. 1 sentence introduction to what was studied.
  2. 1-2 sentences summarizing the procedure
  3. 1-2 sentences with results
  4. 1 sentence conclusion
  5. 1 sentence offering what could skew the data. More on this in the discussion section of this assignment.

The abstract should be written after the experiment is complete.  This is written in the third person passive objective voice.

Example:

Caffeine was extracted from coffee brewed with the drip method and the French Press method. The coffee was brewed with distilled water heated to 88.0 oC. Contact time between the water and grounds was varied in one minute increments. After extraction with ethanol, the caffeine was collected and massed. It was found that coffee made with the French Press method at 88.0 oC with 3 minutes of contact time yielded the most caffeine per mL of coffee at 0.58mg/mL. This data may be skewed by extraction of other compounds preferentially soluble in ethanol. Further analysis will be concluded to determine statistical significance of the data and purity of the caffeine extracted.

 

Materials: (I don’t ask for this on the quiz)

A list or description of materials used.  (I’m totally making this up as I go so these materials are not necessarily needed for this exercise)

  • 50mL graduated cylinder
  • Coffee, cooled
  • Ethanol
  • Scale with 0.0001g precision (Analytical scale)
  • Sodium Chloride

 

Procedure:

Written in the third person, objective passive voice, the procedure provides the basics of what was done.

NOT: Take 50mL of coffee and salt it.  This is active voice.

NOT: A researcher obtained a 50mL sample of coffee. She then put salt in it.  This is 3rd person and passive but not objective. Objective = no people

NOT: Bart weighed out 5g of salt and mixed it into coffee. This is 3rd person and passive but not objective. Think of scientific writing as Magic. There are no people, it just happens. 

WRITE THIS INSTEAD: A 50mL room temperature coffee sample was mixed with approximately 5g of sodium chloride. The mixture was stirred to ensure complete mixing and allowed to sit for approximately 5 minutes.

You would continue this procedure to reflect the entire lab.

 

Results:

The results section contains tables of data, pictures (with your ID) of set up steps or results steps.  All numbers should have units or should have a key with what they mean (i.e. the time in the table below has mm:ss denoting that the numbers to the left of the colon are for the minutes and the numbers to the right are for the seconds.)  Your results would need to be complete for all of the data and observations made in the lab. I have only shown this table with the one set of conditions for illustrative purposes. Note: YOUR SCALE IS NOT THIS PRECISE. The Measurements and Precision lab will show you the precision of your lab ware.

For example:

Table 1: Results of French Press & 3 min contact
88.0 oC Distilled water + Jacob’s Ground Coffee Trial 1 Trial 2 Trial 3
Volume of water 250.0mL 250.0mL 250.0mL
Mass of coffee grounds 30.4067g 31.0245g 29.9901g
Contact time (mm:ss) 3:01 3:00 3:04
Mass of caffeine extracted 0.13mg 0.16mg 0.14mg

 

Discussion

This is the most important part of the lab report. This is where you show your understanding of the experiment and the analysis of the results that were observed. Things to include in the discussion:

  1. Any chemical reaction that takes place (balanced of course – we’ll get there)
  2. Any calculations that were used (picture of handwritten is fine as long as it is big enough and clear enough to be seen with my old eyes)
  3. Lead me through the logical, scientifically sound progression of what was observed.
  4. Lead me to your conclusion.
  5. Evaluate errors in the data.

On Error:

NEVER STATE HUMAN ERROR it doesn’t exist. You can cause all sorts of errors, but those are Determinate errors. They are repeatable and correctable. It isn’t enough to say the data is skewed by determinate error… what is that determinate error. You don’t have to classify the error but explain what that error may cause in your observations.

For example: The caffeine extracted from the French Press method may be skewed by the natural fluctuations of caffeine content found within a bag of coffee. This error could be reduced by mixing the contents of a bag to ensure uniformity of grains. It is possible that all drip coffee values are skewed to the low side because of the flow through design of the method. The contact time variable may not have been as regulated as intended.

  • Errors are typically found in your assumptions.
    • For the above example, it is assumed that the caffeine is evenly distributed in the grounds in the coffee bag.
    • It is assumed that water contacting coffee grounds yields the extraction of caffeine. (mmm tasty)
    • It is assumed that there is a large enough sample size to gather general population data. (This is statistical – that’s my wheelhouse, so I had to leave this in)
    • It is assumed that a 3 minute contact time for French Press is the same as a 3 minute flow through time with the drip method (This is an experimental design flaw that may skew the French Press values upward and the drip method downward.)
    • It is assumed that the caffeine extraction from each cup of coffee is complete.  (This would skew the yield values downward)
    • It is assumed that there are no other compounds extracted with caffeine. (This would skew the yield values upward)
  • Uncertainty of a measurement is called experimental error.
    • Systematic
      • aka Determinate error. Repeatable. Often discovered and corrected.   i.e. I drank 2/3 of each French Press sample therefore didn’t have enough for adequate trials. Ok, we can fix that.
      • Incorrect standardization or calibration
    • Random
      • aka Indeterminate error. Natural fluctuations. Subjective interpretations.
      • Is this solution more blue or more green? Things that are hard to tell could be classified here as random error.
    • Precision vs. Accuracy
      • Precision is the reproducibility of a result. (This is discussed a bit in Module 1)
      • Accuracy is the how close the value is to “true”  (“true” is a statistical term)

Conclusion

State what was learned (not .. “I learned that…”) through the experiment. This is a statement like, “Coffee brewed with the French Press method yielded more caffeine per milliliter of coffee, 0.58mg/mL, than coffee brewed by the drip method, 0.45mg/mL.”  Notice how there is a declarative answer to the hypothesis with factual values. Nothing is vague in that conclusion sentence. Being vague isn’t science.  Let’s science. 😉

 

 

Get 20% Discount on This Paper
Pages (550 words)
Approximate price: -

Try it now!

Get 20% Discount on This Paper

We'll send you the first draft for approval by at
Total price:
$0.00

How it works?

Follow these simple steps to get your paper done

Place your order

Fill in the order form and provide all details of your assignment.

Proceed with the payment

Choose the payment system that suits you most.

Receive the final file

Once your paper is ready, we will email it to you.

Our Services

Paper Helper has assembled a team of highly skilled writers with diverse experience in the online writing circles. Our aim is to become a one stop shop for all your Academic/ online writing. Check out below our amazing service!

Essays

Essay Writing Services

At Paper Helper, we prioritize on all aspects that creates a good grade such as impeccable grammar, proper structure, zero-plagiarism, and conformance to guidelines. The principal purpose of essay writing is to present the author's evaluation concerning a singular subject about which they have made. Since Professionalism is the mother of every success, try our team of experienced writers in helping you complete your essays and other assignments.

Admissions

Admission Papers

You have been trying to join that prestigious institution you long yearned for, but the hurdle of an admission essay has become a stumbling block. We have your back, with our proven team that has gained invaluable experience over time, your chance of joining that institution is now! Just let us work on that essay.How do you write an admission essay? How do you begin the essay? For answers, try Quality Custom Writers Now!

Editing

Editing and Proofreading

Regardless of whether you're pleased with your composing abilities, it's never an impractical notion to have a second eye go through your work. The best editing services leaves no mistake untouched. We recognize the stuff needed to polish up a writing; as a component of our editing and proofreading, we'll change and refine your write up to guarantee it's amazing, and blunder free. Our group of expert editors will examine your work, giving an impeccable touch of English while ensuring your punctuation and sentence structures are top-notch.

Coursework

Technical papers

We pride ourselves in having a team of clinical writers. The stringent and rigorous vetting process ensures that only the best persons for job. We hire qualified PhD and MA writers only. We equally offer our team of writers bonuses and incentives to motivate their working spirit in terms of delivering original, unique, and informative content. They are our resources drawn from diverse fields. Therefore your technical paper is in the right hands. Every paper is assessed and only the writers with the technical know-how in that field get to work on it.

Coursework

College Essay Writing

If all along you have been looking for a trustworthy college essay service provider that provides superb academic papers at reasonable prices, then be glad that you search has ended with us. We are your best choice! Get high-quality college essay writing from our magnificent team of knowledgeable and dedicated writers right now!

Coursework

Quality Assignment/Homework Help

We give the students premium quality assignments, without alarming them with plagiarism and referencing issues. We ensure that the assignments stick to the rules given by the tutors. We are specific about the deadlines you give us. We assure you that you will get your papers well in advance, knowing that you will review and return it if there are any changes, which should be incorporated.