One circadian rhythm that is easy to keep track of is your own body temperature. Get an oral thermometer such as the one you use when you are sick. Make sure you know how to use it properly!! Measure your temperature every 2 hours from the time you get up in the morning to the time you go to sleep. (If you can't measure your temperature every 2 hours, then just measure it as often as it is feasible). Don't eat or drink anything right before you take your temperature. Make sure to take your temperature the same way every time and that you read the temperature VERY ACCURATELY....the differences in your body temperature are only a few 0.1 of a degree. Chart your body temperature with time...use the X axis for "Time of Day" and Y axis for "Body Temperature". Do you see a pattern?
An additional activity to do with the body temperature measurements is to combine the reaction time experiment. Measure your reaction time to catching the ruler and plot your "catch times" with your body temperature. Is there a correlation? Is your reaction time faster or slower with warmer body temperatures?
|Did you know?||Normal body temperature can vary up to 2oF in a 24 hour period. The highest body temperature ever recorded was 115oF. Body temperatures of 109oF can be fatal. (Statistic from Prevention's Giant Book of Health Facts, 1991.)|
People have biological rhythms...what about other creatures? 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. Therefore, one person can measure the amount of time spent eating, another person can watch for sleeping, etc. Do not disturb the animal while you are observing it. Chart the amount of time spent in each behavior at different times of the day. Keep track of it for several days. Are there any consistent patterns?
Sometimes it seems as if time flies by....sometimes it drags on forever. How good are you at estimating time? Do you have a built in stopwatch? Here are two ways to test the built in stopwatch:
Try several different time periods (5 seconds, 15 seconds, 30 seconds, 60 seconds, 90 seconds) and see if performance gets better or worse.
On-line Time Estimation Experiment - How accurate are you at estimating time?
How many times have you set your alarm clock for a particular time only to wake up a few minutes before it rings. You find out you didn't need the alarm clock at all because you woke up without it. How good is your "built-in alarm clock"?
This experiment is best done in the summer on a weekend or some other time you don't have to wake up at a special time. Before you go to sleep, determine what time you want to wake up, but do not set your regular alarm clock. The wake up time should be a time that you usually wake up. For example, if you wake up to go to school at 7 am., tell yourself to "Wake up at 7 am." Then just go to sleep and see what time you wake up.
If you have a few days to try this, keep track of your wake up times to see if you come closer to your built-in alarm clock's setting. You could even graph how far off you were from the time you wanted to wake up by graphing number of minutes away from your built-in alarm clock's setting. For example, if on the first day you woke up at 7:10 instead of 7:00, you would be off by 10 min. If on the second day you woke up at 7:08 instead of 7:00, you would be off by 8 min. See if there are any patterns to your graph.
Don't blame me if your built-in alarm clock doesn't work to wake you up. DO NOT do this experiment when you have to wake up a special time (such as a school day)! Your built-in alarm clock may FAIL and you will be LATE. You may want to set a real alarm clock as a back up system!
Experiment 5: A Yawner Grades 4-12
No one really knows the cause and purpose of yawning. However, yawns do appear to follow a daily cycle. Yawns seem to occur most often soon after waking and about an hour before bedtime. See if your yawning behavior has a similar cycle.
Keep track of the number of your yawns and the time that they occur from the time you wake up to the time you go to sleep. Print out this YAWN worksheet to record your yawns. The most difficult part of this experiment is remembering to record every one of your yawns, so keep the worksheet is a handy place.
Add up the number of yawns that occurred in each half hour period and plot them out on a graph. Use the time of day on the X-axis and the number of yawns on the y-axis. Compare your graph with the graphs of other people.
See Circadian Technologies and the Society for Neuroscience page on biological clocks for more about nature's rhythms.