1. How to Write a good Lab Report

2. Isolated conclusion from a report on mapping magnetic fields Sample Lab Conclusion Paragraph:
Background information:
Initial hypothesis: Magnetic field strength will be proportional to the strength of the current running through a straight wire and inversely proportional to the distance from the wire.
The data collected correlated strongly to the hypotheses, albeit with percent errors reaching as high as 20% [uncalibrated]. (Other sections of this report detailing this information have been removed from this example.)
The trends in the data support the hypotheses that the strength of a magnetic field was proportional to the current running through a straight wire and inversely proportional to the distance from the wire. However, the significant percent error may indicate mechanical error, which must be accounted for in future experiments.
The accuracy of the results could be improved with better equipment. Instruments capable of measuring the strength of the magnetic field to a more precise number would likely result in a more accurate slope and therefore a smaller percent error. Similarly, although the probe was zeroed between all measurements, there is a chance that magnetic fields generated by electronics in the room might have affected the measurements taken. In the future, the experiment would need to be more isolated to generate better results.
The use of voltage and current in this experiment compels the experimenter to question whether a resistor would behave in the same manner a straight wire does in this setting, or whether the presence of a resistor further up in the circuit might change the magnetic field in any way. Experimentation with a resistor in the circuit would be necessary to determine this.
Sample Conclusion

3. Your teacher might give you a handout detailing what the assignment requires, or he or she might write the requirements on the board. Whatever it is, make sure you have the complete instructions and understand them well. If you don't, ask your teacher for help ahead of time (in advance of the night before it's due). Here's a basic format for most lab write- ups:
Research: What did you do to gather information about your problem?
Hypothesis: What statement is the experiment testing?
Reason for your hypothesis: How did you come up with the hypothesis?
Procedure: If your teacher gave you instructions use the procedure given. If not, explain what you are doing.
Analysis/Results: What really happened? Provide data and charts here.
Conclusion: What do you conclude about this experiment? Why?
Lab Report

4. Refer back to your Notes
Take thorough notes. It's important for later use. Your teacher will always go through all outcomes of lab experiments. These notes will help you in the future, so never underestimate them. Try to be concise: don't write things you don't need.
It might be tempting to over-highlight your notes, but resist. If you only wrote down the important information, you shouldn't need to highlight anything.
Refer back to your Notes

5. Know the hypothesis. REFER BACK TO THE HYPOTHESIS Every scientific experiment has a hypothesis. A hypothesis is simply a statement about what you expect the experiment to do. The results of the experiment then either support or disprove the hypothesis.
HYPOTHESIS

6. DISPROVED OR SUPPORTED
Understand whether the hypothesis was disproved or supported. In your report, clearly outline what the hypothesis of the experiment was, and whether or not the results supported it.
DISPROVED OR SUPPORTED

7. Analyze and present data correctly
Analyze and present data correctly. Ask yourself why the result is what it is. If there is an anomalous result/value (a value that is not synchronized with the other values), question why. If you have an answer, take down some notes so that you will not forget it in your report. Below are types of data for lab experiments: Value-based data: All of your data is in number form. In this case, you might need to draw a graph to present your conclusion. After drawing graphs, make relationships between the factors that were tested in the experiment. For example, you might say increasing the amount of light, will shorten the amount time for germination in a pea plant.
Statement-based data: Your data is completely based of observations, such as color change, types of reactions, and other phenomena that do not involve numbers.
ANALYZE YOUR DATA

8. Identify one key source of experimental error that took place (optional). If something happened to alter or affect the results of the experiment that shouldn't have happened, explain it. For instance, the wind that passed by reduced the temperature of reactants and therefore made the reaction slower than expected. A suggested way of answering will be the following.
EXPERIMENTAL ERROR

9. FINALIZE THE CONCLUSION
End with a conclusion. In your conclusion, neatly sum up what you learned from the experiment. Did the hypothesis teach you anything? Were the results what you expected? Why or why not? Use evidence from your lab to support your answer.
FINALIZE THE CONCLUSION

10. SUMMARY
Instructions
1 Use elements from the introduction in the conclusion. Their structure must be similar. If you are having difficulty writing the conclusion, re- read the introduction for ideas about what to write.
2 Include an analysis of the results when writing a conclusion or discussion section of a lab report. Link the results to what you read in the literature, review or other sources mentioned in the introduction.
3 Discuss whether or not the results supported your hypothesis. If they did not, discuss why not.
4 Suggest biases that may have affected the experimental design. Discuss how they can be eliminated in the future. Discuss the possibility of using a different methodology or design.
5 Write about how the experiment can be improved in future replications.
6 Discuss the significance of the experiment, if it resulted in the creation of new knowledge, added support to a recently developed theory or aided in the formulation of new questions to be researched. Consider also that the experiment may have been a complete waste of time.
Tips & Warnings
Always use past tense when writing the discussion or conclusion section of a lab report.
Incorporate the specific guidelines given to you by your instructors.