Measure your temperature every 2 hours from the time you get up in the morning to the time you go to sleep. Don't eat or drink anything right before you take your temperature. An additional activity to do with the body temperature measurements is to combine the reaction time experiment. Normal body temperature can vary up to 2 o F in a 24 hour period. The highest body temperature ever recorded was 115 o F. Body temperatures of 109 o F can be fatal.
Many schools have classroom pets - a rat, rabbit, hamster, fish or frog.
If your class has a pet, study its behavior to see if you can determine any cycling patterns. For example, if you have a rat, observe the amount of time it spends eating, walking and sleeping at different times of the day. Check on it every 2 hours and watch it for 10 minute periods. It is best if a group of students helps out. Assign 1 behavior to each student.