lot can be done with just a digital thermometer and a good notebook!
temperature drops at night, as part of the normal circadian rhythm
(the so-called body clock). Women reach their minimum body temperature
earlier than men, People who feel most awake in the evening have
lower nocturnal temperatures.
the temperature cycle different between sexes?
age affect the temperature cycle?
outside weather conditions affect body temperature?
exercise at different times of the day affect your body temperature
there a correlation between body temperature and concentration,
mood, learning etc.
Google for information on body temperature: