1. Begin by asking the class, Do you think you get all the sleep you need every night? How do you feel the day after you have not slept enough or not slept well?

Students may respond that if they haven’t had enough sleep, they feel drowsy, not alert, cannot think properly, and have less energy.

2. Ask, How much sleep per day is necessary for good health? Write the responses on the board.

Students may respond that eight hours of sleep per day are needed for good health. Other students, based on their own experience, may believe that only five or six hours of sleep are needed for good health.

3. Ask the class, What would happen to us if we were not allowed or able to sleep at all for a long period of time (such as several days in a row)?

Among other responses, students may say that they would eventually die from lack of sleep. (It is known that severe sleep deprivation can produce behavioral changes and hallucinations in humans. No human, as far as science is aware, has died from lack of sleep. However, laboratory rodents will die if not allowed to sleep.) If no student mentions this possibility, initiate a discussion of what human behaviors are required for us to survive. Students should begin to consider sleep an essential behavior, and they should begin thinking about what sleep does for us.

When discussing what behaviors are necessary for survival, a graphic organizer such as the following may prove useful in summarizing the discussion.

Figure 1.1. Graphic organizer.

Students will recognize that breathing, drinking, and eating are essential for life to continue. We can do without breathing for only a period of minutes, in contrast to drinking (days) and eating (weeks). This discussion should help students understand that sleeping is another essential behavior, one that is required for survival.

4. Explain to the class that you now are going to explore what they know about sleep. Stress that this activity is not a test and that their responses will not be graded.
5. Give each student a copy of Master 1.1, What Do You Know (or Think You Know) about Sleep? Stress that their answers will help them gauge their own understanding of sleep.
6. After the class has had a few minutes to complete their responses, engage the students in a discussion of why they answered as they did. If you prefer, have students write their responses on a piece of paper.

1. Go to the Web site page http://science.education.nih.gov/supplements/sleep/student and click on “Teacher Database Administration.”

• When prompted, enter the username “sleepadmin” and password “admin” (all in lowercase letters ).
• Enter the requested information on the form.

For the latitude entry, refer to the latitude map. If your location is equally distant from two latitude lines, then enter the higher one.

2. Once you have entered your class information, click on “Generate Class Codes.” You will receive a unique class code for each class that you entered on the previous form. Each class code consists of a color followed by a five-digit number.

• Next, click on “Done”; this will take you back to the Web site home page.
• Click on “Web Portion of Student Activities” (or have students log onto the student Web site) and then on “Lesson 1—What Is Sleep?”
• Enter the unique class code that you were assigned (and that was e-mailed to you) to access the pages for entering data, viewing data, or creating reports. At this site, you (or your students) may enter the averages from each student’s sleep diary (that is, average bedtime, average wake time, average number of awakenings, average total sleep time, average number of caffeine-containing drinks for morning, afternoon, evening) along with each student’s corresponding sleepiness scale scores.
• Note that after entering an average bedtime and wake time, the computer will calculate the average total sleep automatically.

3. Instruct students to work individually or in small teams. They should develop a hypothesis, test it by using the data in the sleep database, and provide a short, written summary of their findings.

When using the Web version of this activity, students have the opportunity to analyze a much larger database. They can generate many different hypotheses and reports keyed to specific descriptors to test each hypothesis, as described below.

Students have a number of options for building custom reports of records in the database, such as

1. all students who have entered data
2. females who have entered data
3. males who have entered data
4. those who have entered “yes” to snoring
5. those who have entered “no” to snoring
6. those who have entered “yes” to sleeping difficulties
7. those who have entered “no” to sleeping difficulties
8. those with a specific total sleep time

Content Standard A:
Design and conduct scientific investigations.

Content Standard A:
Communicate and defend a scientific argument.

There are many more options. These summary reports provide the calculated average for each parameter based on the portion of the database that you selected. This database allows students to formulate and test many different hypotheses by generating the appropriate report and evaluating the resulting data. For example, hypotheses that can be tested by using information in the database include

• Males sleep longer than females.
• Evening consumption of two or more caffeinated beverages results in later bedtimes.
• People go to bed earlier in the winter months.
• Snoring is associated with more frequent awakenings during the night.

Students are limited by their imagination, but their hypotheses must be answerable using the available data.

4. After the class has had the opportunity to test their hypotheses, ask for a volunteer to report his or her hypothesis and findings. Ask the student why he or she chose that hypothesis.

Make sure that students are testing hypotheses that can be investigated using the available data.

5. If a student isn’t sure that the data support the hypothesis, ask why and consider what additional data could help resolve the question.

Even if the student has asked an appropriate question of the database, there may be too few entries to reach a firm conclusion. The database can address questions regarding the effects of gender, snoring, and caffeinated drinks but does not contain information to address other variables such as the effects of dreaming, allergies, or physical exercise.

This is an opportunity to discuss what types of data are needed to properly evaluate a hypothesis.

Assessment: Instruct students to write a brief report that states their hypothesis, the data from sleep diaries used to test it, and their conclusions. If the data do not support a firm conclusion, instruct students to explain what additional information would be needed to reach a conclusion.

6. As time permits, ask other students to report their hypotheses and findings. Try to elicit different hypotheses.

To enrich the discussion, encourage students to ask questions and challenge the conclusions of the presenters.

7. To conclude the activity, explain to the class that people feel pressure to sleep in daily cycles. Scientists refer to this need-to-sleep cycle as “homeostatic regulation.” Ask students to draw a graph that depicts the need to sleep (on the y-axis) versus the time of day (on the x-axis).

Students should conclude that the need to sleep increases throughout the day, reaching some level that is sufficient (in combination with other factors) to induce sleep. Sleep itself causes a decline in the need to sleep. This is depicted in Figure 1.2.

Figure 1.2. Homeostatic regulation of sleep refers to the pressure or urge to sleep. Sleep pressure increases (dashed line) as one stays awake longer into the normal sleeping hours.

Students may depict the line as more linear than not. The important point, however, is that homeostatic regulation of sleep is cyclic, rising during wakefulness and then declining during sleep.

8. Ask the class what the graph would look like if it represented an individual deprived of sleep during the day and night.

Students should show the line continuing to increase throughout the period of sleep loss. The pressure to sleep does not reach a plateau but continues to increase until sleep occurs and the pressure (or need to sleep) declines.

1. Collect data from the student sleep diaries. Instruct students to write their data on the board. Compile their data for the following categories:

1. average bedtime
2. average wake time
3. average number of awakenings during the night
4. average total sleep time
5. average number of caffeine-containing drinks in morning, afternoon, and evening
6. number of students who snore
7. number of students who report sleeping difficulties

2. Instruct students to calculate the class average for each of the items a through e in Step 1.

Content Standard A:
Design and conduct scientific investigations.

Content Standard A:
Communicate and defend a scientific argument.

Content Standard A:
Students should develop abilities to formulate and revise scientific explanations and models using logic and evidence.

Please ensure that a copy of the class data is retained for later reference. Ask students to a) compare their own data with the class data (for example, How does their average total sleep time compare with the average total sleep time of the class?); b) compare the data entered by males with that entered by females; and c) determine whether there is a correlation between evening consumption of caffeine and average bedtime or average total sleep time.

3. Ask the class to generate a hypothesis about sleep that can be answered using the class data.

There are a number of possibilities. For example, students might hypothesize that individuals who snore sleep less per night than individuals who do not snore. Another possibility is that students might observe that their calculated average sleep time is quite unlike either their usual weekday sleep times or their usual weekend sleep times. Perhaps students are sleeping far less on weekdays than on weekends. Such analysis leads to discussion of sleep debt and good sleep habits, which will be addressed in Lessons 4 and 5. There is also the option of compiling data separately for males, females, and the class as a whole.

4. To conclude the activity, explain to the class that we feel pressure to sleep in daily cycles. Scientists refer to this need-to-sleep cycle as “homeostatic regulation.” Ask students to draw a graph that depicts the need to sleep (on the y-axis) versus the time of day (on the x-axis).

Students should conclude that the need to sleep increases throughout the day, reaching some level that is sufficient (in combination with other factors) to induce sleep. Sleep itself causes a decline in the need to sleep. This is depicted in Figure 1.2.

Students may draw the line more-or-less linear. The important point, however, is that homeostatic regulation of sleep is cyclic, rising during wakefulness and then declining during sleep.

5. Ask the class what the graph would look like if it represented an individual deprived of sleep during the day and night.

Students should show the line continuing to increase throughout the period of sleep loss. The pressure to sleep does not reach a plateau but continues to increase until sleep occurs and the pressure (or need to sleep) declines.