My astronomy teacher in high school was a complete autocrat about scale for all his diagrams and all our student illustrations on tests (he'd mark you down for doing a drawing and not adding "Not to scale"!). In his field, this makes a lot of sense.
Without the note on scale, someone looking at a drawing of the earth, moon, and sun for the first time could think they're all nearly the same size and VERY close together.
I owe him a great deal, because his vehemence has always stuck with me. And it feeds pretty well into my topic today: the nitty gritty of lab notebooks.
That's right, all the potentially unexciting data that has to be recorded along with your more engaging observations.
This includes:
Scale, or size, usually demarcated in meters, kilometers, milimeters depending on subject
Date and time–especially important for time-sensitive phenomena like tides, embryonic development, and long duration experiments
Temperature/atmospheric conditions–more important for field notes than laboratory notes, though to some extent embryonic development can be temperature dependent
If you have to improvise measuring some of these, that's okay! For scale you can use coins in your pocket or how tall something was relative to yourself (I even know someone who had a scale bar in centimeters tattooed on the side of his forefinger so he would never be without a ruler!)
As for temperature and atmospheric conditions, even a note like "hot as hell and cloudy" is better than nothing for your field notes! If you've included the date and time you can also always go back and add in exact temperature after checking the weather reports for that area.
Scale bars here put in perspective a larval sea urchin and an adult sea urchin. Date, time, and temperature are quite important even in lab situations when there's larval or embryonic development going on.
The reason to take these notations? You risk not remembering these things later, but more importantly, another person who wasn't there with you wouldn't know this background info. There may be key details in the weather or the size of your subject that you don't know yet are key!
Next week on Lab Notebook Tips: tips for drawing!
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