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NOVA scienceNOW: Sleep
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Viewing Ideas
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Before Watching
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Record information about sleep habits. Starting the week
before you view the program, have students record four kinds of
their own sleep-related data—hours of sleep, general mood,
physical energy, and mental alertness. Ask them to record the
data for a five-day period and enter it in bar graphs on the
Why Sleep Matters graphing sheet.
After five days of data collecting, have students form groups
and discuss their logs. What was the average number of hours
each person slept per night? How does this compare to what
doctors recommend (between nine and ten hours)? Was there a
common pattern in relation to daytime alertness/sleepiness? Have
a recorder from each group make a list of common findings. Then
have groups share their results with the class.
As an extension, have students also record the following
information about their sleep behavior and discuss it when they
meet in groups:
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The time they went to bed and got up the next morning
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A general statement about how they slept, and possible
reasons for their good or poor night's sleep
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A log of their level of alertness/sleepiness, in which they
record every two hours during the day how alert/sleepy they
feel, using a scale of one to five (one equals least sleepy,
five equals most sleepy).
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Play a game to review sleep-related vocabulary. Have
students play the word game
Choose the Correct Meaning
to familiarize them with vocabulary terms related to sleep and
memory. Divide the class into three or four teams. Read a
vocabulary term and the three possible definitions aloud. Have
teams take turns identifying the correct definition for each
term.
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Design a poster about sleep. Divide the class into four
groups and have each group research the questions below and
present their work in a poster. (You may choose to have groups
present information in a health-brochure format.) See the Links
and Books section for sources of this information.
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What are rapid eye movement (REM) and non-rapid eye movement
(NREM) sleep? What are the differences between these two
types of sleep?
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What is the body's biological clock? Why is it beneficial to
stay on a set sleep schedule? What are the sleep
requirements for people of different ages?
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What is sleep debt? What kinds of activities are
affected by a lack of sleep?
What are some common sleep disorders?
(Suggested source:
http://science.education.nih.gov/supplements/
nih3/sleep/guide/info-sleep.htm)
After Watching
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Make a model of the human brain. Have student teams make
a clay or Plasticine model of the human brain. (Or, provide
students with a diagram of the brain for this activity.) The
program highlights two brain regions, the hippocampus and the
neocortex, where nerve cells show coordinated activity during
sleep. As students make the brain models, have them use bright
colors to indicate the hippocampus and the neocortex. Ask teams
to label the different regions of the brain using toothpicks
with labels attached.
Have students research and then write on an index card the basic
function of each region of the brain. (Include frontal,
temporal, and parietal lobes, the cerebellum, and the brain
stem. The hippocampus is in the temporal lobe. The neocortex is
the top layer of the frontal, temporal, parietal, and occipital
lobes.)
(Suggested sources:
www.pbs.org/wnet/brain/3d/index.html
and
http://brainmuseum.org/functions/)
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Play a game demonstrating how information storage relates to
memory.
Researchers have shown that long-term memories are embedded in a
web of neural connections. Individual memories aren't stored as
distinct "files," separated from all others. Rather, many
connections exist among a person's memories. To demonstrate this
phenomenon, read aloud a list of eight unrelated words, such as
tub, grass, car, ring, chair,
cow, juice, and star. Then have students
write down as many words as they can remember. As a class, list
the words. The class will likely be able to recreate the list of
eight words, but individuals are less likely to get them all.
Next, read, in a mixed-up order, an eight-word list that
contains four pairs of closely linked words, such as eye,
nose, boy, girl, apple,
orange, salt, pepper. Again, have students
write down as many words as they can remember. When recalling
the list, most students will write related words together
because such words are strongly connected in people's long-term
memory network or web.
Another way our brains remember information is by grouping it in
meaningful "chunks." In the above example, students remember
four pairs, or chunks, rather than eight individual words. To
retest "chunking," ask students to see how well they can
remember the next group of clustered letters: THEB IGDO GCHA
SEDT HOSE ORAN GECA TS. Then regroup the letters: THE BIG DOG
CHASED THOSE ORANGE CATS and have students explain why the
second group was easier to remember. (A sentence is like one chunk of information. All the words in
the sentence are familiar. The brain makes an image of the
sentence.)
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Play games that test short-term memory. The program
discusses how sleep may help the brain process short-term
memories. Have students brainstorm the definition of a
short-term memory (a memory of an event that lasts from several
seconds to a few minutes). Then divide the class into groups and
have each group play the following three short-term-memory
games. Conclude with a class discussion about why seeing
something multiple times might reinforce memory. (Neural connections may be enhanced.)
What's on the Tray?
Materials for each group: tray, 25 different common items, towel
Procedure: Provide each group with a covered tray of items. Have
each group remove the cover, observe for 25 seconds, and then
cover the tray again. Individual students should write down all
items they remember. Try the game a second time. Have groups
share general results. The hypothesis is that students will
remember more after two trials because their initial observation
was reinforced by the second viewing. Do the class data support
this hypothesis?
What Was Taken?
Materials for each group: tray, 25 different common items, towel
Procedure: Provide each group with a tray of items. Have
students observe their tray for 25 seconds and then close their
eyes. Ask a designated member from each group to remove one item
from the group's tray. Then each person tries to identify what's
missing. Repeat the game a few times.
Again, have groups share results. Were students better able to
discover which item was missing after the second or third trial?
Which Cities?
Material for each group: a story that is a few paragraphs long
containing the names of 5 to 10 well-known cities. You may
choose to write a story about a class trip, a sports event, or a
student discussion related to traveling.
Procedure: In each group, one person reads the story aloud while
the others listen. When the story is finished, group members
should try to list the names of the cities in the story. Repeat
and see how much difference a second reading makes.
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Hypothesize some reasons why sleep may be important for
different kinds of animals.
Researchers have found that even fruit flies need sleep. Sleep
is important for our survival, and for some animals, it seems be
important to learning and memory. Provide students with the
information in the first two columns of the table below. Do
students see any patterns? Then have the class hypothesize some
reasons why sleep may be important for different kinds of
animals. (Be sure to let students know that only a few different types
of animals have been subjects in laboratory sleep and memory
studies. Students are only proposing hypotheses.
Accept reasonable answers.)
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Animal
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Average Daily Amount of Sleep
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Sample Hypotheses for the Role Sleep Might Play in
Consolidating Memory
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Brown bat
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19.9 hours
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To process routes they travel, finding food, and avoiding
predators
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Human infant
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16.0 hours
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To process new information from the surroundings
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Squirrel
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14.9 hours
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To process where food is located and hidden
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Cat
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12.1 hours
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To process strategies for capturing food and prey
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Rabbit
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11.4 hours
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To process location of food and ways to avoid predators
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Dog
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10.6 hours
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To process social and training experiences
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Bottle-nosed dolphin
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10.4 hours
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To process their songs
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Chimpanzee
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9.7 hours
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To process social interaction and locating and accessing
food
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Human adolescent
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9.3 hours
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To process social interaction and learning experiences
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Human adult
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8.0 hours
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To process social interaction and learning experiences
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Elephant
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3.5 hours
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To process social interaction and locating food and water
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Giraffe
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1.9 hours
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To process memories related to location of food and water
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Data for animal sleep times obtained from:
http://science.education.nih.gov/supplements/
nih3/sleep/guide/info-sleep.htm
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Learn about "daily rhythms" by performing an activity
measuring reaction time. While the segment considers the role sleep may play in
learning and memory, many factors can affect performance. For
example, most living organisms follow a circadian rhythm,
an "internal body clock" that regulates a roughly 24-hour cycle
of biological processes. Yet even with such a biological
"clock," there is variation in people's daily rhythms, with
different people experiencing such things as hunger, maximum
alertness, and tiredness at different times of the day. People
often acknowledge these differences by describing themselves as
early birds or night owls.
Explore students' circadian rhythms by having them identify the
time of day they experience their peak performance. Have them
brainstorm some of factors that might affect performance, such
as when a person last ate, one's mood, the time of day, and
events that occurred that could interfere with the ability to
focus. Ask, "How do you think time of day influences our actions
and behavior?" (Some people are more alert, feel better, and perform better
during the morning; others during the evening.) Tell students that these time-of-day changes are called
circadian rhythms, and they contribute to how we perform
and feel throughout the day.
Have students rank themselves as an early bird or night owl,
based on what they think are their times of highest alertness.
(Early birds are most alert before noon and night owls are
most alert during the evening.) Discuss the Student Reaction Time Activity below, and
either copy the procedure onto the board or onto a handout. Give
each student four pieces of grid paper, and do the first trial
in class. Ask students to complete the remaining three trials
before the next class meeting.
Student Reaction Time Activity
Materials: Reaction Time Chart, 4 sheets of 1-cm grid paper,
pencil, timer (seconds and minutes)
Procedure: On the Reaction Time Chart, mark whether you
are an early bird or a night owl. Set the timer for one minute.
Start the timer, and mark as many grid-squares as possible with
a check mark. After a minute, count the number of squares
checked. Record your results in the chart.
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Reaction Time Chart
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I think I'm more of: ___an early bird ___a night owl
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Time of Day
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Number of checkmarks
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Early morning
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Mid morning
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Around dinnertime
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At bedtime
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Before the next class period, make a class-data chart on the
board like the one below. Have students share their results by
placing a check in the space that matches their designation and
the times of their highest and lowest scores. Once the chart is
complete, have students see if the data supports the idea that
performance is influenced by time of day. Emphasize that one's
circadian rhythm impacts alertness and, therefore,
learning, memory, and performance. Have students brainstorm how
a person's circadian rhythm could play a role in activity
choices (e.g., playing games late at night or playing sports
early in the morning); work or career choices (e.g., being an
emergency-room surgeon or an air-traffic controller); and
personal choices (e.g., whether one gets sufficient sleep). Also
ask about what people can do to make adjustments when their
school or work schedules conflict with their natural rhythm (e.g., take naps). End the discussion by brainstorming variables that may have
influenced the activity results. (Students may have experienced different stressors, amounts of
sleep, or levels of nutrition.) Have students suggest controls that would make the
investigation more reliable. (Some students may suggest keeping participants in a more
uniform environment that would better control sleep, stress,
and diet.)
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Time of Day
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Early-Birds
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Night-Owls
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Place an "X" when you got your highest score
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Place an "X" when you got your lowest score
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Place an "X" when you got your highest score
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Place an "X" when you got your lowest score
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Early morning
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Mid morning
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Around dinnertime
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At bedtime
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Web Sites
NOVA scienceNOW
www.pbs.org/nova/sciencenow/3410/01.html
Offers sleep-related resources, including additional activities,
streamed video, and reports by experts.
Are You a Lark, an Owl, or a Hummingbird
nasw.org/users/llamberg/larkowl.htm
Presents an excerpt from a book about daily rhythms and the body
clock.
Clockwork Genes
www.hhmi.org/biointeractive/clocks/index.html
Contains four animations on biological clocks, pertinent articles,
and an online biological clockworks exhibit.
Information about Sleep
science.education.nih.gov/supplements/nih3/sleep/guide/info-sleep.htm
Includes information about the sleep cycle, sleep requirements, the
function of sleep, and sleep disorders.
Neuroscience for Kids
faculty.washington.edu/chudler/chmemory.html
Provides a variety of memory-related experiments.
Power Nap Prevents Burnout; Morning Sleep Perfects a Skill
nimh.nih.gov/Press/sleep.cfm
Summarizes "power nap" and sleep studies that suggest sleep enhances
some types of learning.
Researchers Find the Snooze Button
www.hhmi.org/news/sehgal20060608.html
Describes research using fruit flies which considers the role of
"mushroom bodies" on regulating sleep.
Sleep Forms Memory for Finger Skills
www.pnas.org/cgi/doi/10.1073/pnas.182178199
Describes results of a finger-to-thumb motor skill task. Findings
indicate that sleep is important for consolidation of motor skill
memories.
Books
The Body Clock Guide to Better Health
by Michael Smolensky and Lynne Llamberg. Henry Holt and Co.,
2000.
Discusses the importance of body rhythms in relation to health.
The Promise of Sleep
by William C. Dement and Christopher Vaughan. Dell, 2000.
Describes sleep disorders and discusses the importance of sleep.
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