When working in research one must have a lab notebook to document ones findings. There is not many rules to this living document however it should be clear and concise what you are doing for each experiment and/or discovery that you find. The document is also a reference to previous successes and problems you had in the past. I am sure if you had an issue with lab equipment or some mechanical failure one might have wrote the variables that may or may not have caused it. For example , I worked with an electro spinner. One day I wondered why I could not get fibers to spin. I looked in my lab notebook and noticed that humidity helped in the processing of forming fibers, in general. Wouldn’t you know, once I added humidity I was able to get fibers. Therefore, the lab notebook is critical.