"I applaud him, but that's not good lab technique. Good lab technique is "Here's my lab notebook. You can see my data along with the handwritten timestamps." I

"I applaud him, but that's not good lab technique. Good lab technique is "Here's my lab notebook. You can see my data along with the handwritten timestamps." I don't think he had much choice other than to say back because his comment was made at the end of the morning's lab session which ended at lunchtime. As was his wont, he walked around the lab near the end of the session looking at students' results. It would not have been easy to 'prefabricate' results ahead of time for two reasons, the first is that whilst the type of experiment was known to students ahead of time the exact details such as the quantity of reagents etc. were not; second, lab work notes required not only time and date but also the lab temperature, atmospheric pressure and humidity to be entered at the beginning of the work (and occasionally these were relevant and had to be taken into account). Students acquired this info from instruments, barometer etc., on the lab wall near the entrance (we usually wasted about 5 mins crowded around whilst each student recorded the details separately). BTW, these were analog instruments, wet and dry bulb etc., thus the measurements consumed noticeable time. For brevity's sake what I didn't mention was that there were two of us involved in the experiment, thus, by necessity, we both had to have the same results. As was the practice, students did lab work in pairs (each bench had room for two students) so both of us were implicated (although I was the one he addressed). The titration was only part of a larger experiment, what he implied was that the data points on our hand-drawn graphs (done during the lab work) which showed various stages of the titration didn't come from the experiment itself but that we'd inferred (interpolated) them from textbook info that we'd have known ahead of time. In theory, he was of course correct, knowing the textbook theory it wouldn't have been that difficult to interpolate the results on-the-fly. As two of us were involved, by implication he also implied collusion (although he didn't say so). All I can say is that his mind was more devious than ours. For starters, neither of us was that organized and looking at a list of the work we'd be doing each lab session that had been issued months before wasn't something that I did (again, such dedication eluded me—too many other distractions). The other point was that whilst accuracy in one's lab work was important, it's not as if we were awarded marks on accuracy, what mattered was actual attendance at the lab and successful completion of the experiment—so planning ahead like he implied would have been the last thing on our minds. "You had to record EVERYTHING in your lab notebook. Serial numbers of equipment, test and calibration procedure steps, data that you knew was invalid and record the reason why ... all in pen with timestamps with no erasures ever allowed." Right, there's nothing wrong with this and getting students into the habit of calibrating their setups/experimental equipment is absolutely important. In fact, for me this started in science from the first year in high school and followed on at university. Calibration is still ingrained on my mind (later in life I was involved in standards work so such thinking comes naturally). That said, the way of policing lab work is for the instructor to walk around during the experiments and ensure that such recordings are done on the spot. As mentioned, when I was doing lab practical the emphasis was on a successful outcome on the day—results later on weren't that important, actually learning to do it properly was what mattered. ""If you can't get the same result three times, you don't even know that you're wrong let alone that you're right."" There's a lot to that which makes sense, however, what we were taught was that you'd be unlikely to get exactly the same result each time because of experimental error. Getting the same identical result wasn't as important as checking one's technique each time and then correlating each set of results thereafter. In fact, we were warned that if one got identical results then to be suspicious—some equipment, setup etc. may not have been properly reset from the previous run of experiments, etc. What was more important, beginning even in first year of high school science, was to process one's results statistically. That meant summing residuals etc. using stats—nth root n-type stuff. Various statistical techniques were applied in both physics and chemistry and applied right through my training.