Activities Guide for Teachers - University of ArkansasSaundra Saunders, Angi Signorelli, and Marcia...

Activities Guide for Teachers

National Space Biomedical Research InstituteHouston, Texas

The National Space Biomedical Research Institute (NSBRI) is combining thebasic research capabilities of some of the nation’s leading biomedical researchcenters with operational and applied research conducted by the NationalAeronautics and Space Administration (NASA) to understand and achieve safeand effective long-term human exploration and development of space. TheNSBRI’s discoveries and research products will help to counter the effects ofweightlessness and space radiation and will contribute to the health and well-being of all mankind.

National Space Biomedical Research InstituteOne Baylor Plaza, NA-425Houston, Texas 77030-3498http://www.nsbri.org

The activities described in this book are intended for school-age children underdirect supervision of adults. The authors, Baylor College of Medicine and theNational Space Biomedical Research Institute cannot be responsible for anyaccidents or injuries that may result from conduct of the activities, from notspecifically following directions, or from ignoring cautions contained in thetext. The opinions, findings and conclusions expressed in this publication aresolely those of the authors and do not necessarily reflect the views of BaylorCollege of Medicine or the National Space Biomedical Research Institute.

Authors: Nancy P. Moreno, Ph.D. and Barbara Z. Tharp, M.S.Cover Illustration: T LewisDesign and Production: Martha S. Young

AcknowledgmentsThe authors gratefully acknowledge the support of Bobby R. Alford, M.D.;Laurence R. Young, Sc.D.; and Ronald J. White, Ph.D.; as well as the contributions of the following science reviewers: Mary A. Carskadon, Ph.D.;Kimberly Chang, Ph.D.; Charles A. Czeisler, Ph.D., M.D.; David F. Dinges,Ph.D.; Hans P.A. Van Dongen, Ph.D.; and Kenneth P. Wright, Jr., Ph.D.Preparation of this guide would not have been possible without the invaluableassistance of the following field test teachers: Yolanda Adams, Jeri Alloway,Vivian Ashley, Susan Babac, Henrietta Barrera, Paula Clark, Carol Daniels,Barbara Foreman, Carolyn Hopper, Susan King-Martin, Mary Helen Kirby, SueKlein, Jacqueline McMahon, Sandra Prill, Carol Reams, Mary Ellen Reid,Saundra Saunders, Angi Signorelli, and Marcia Wutke.

The National Aeronautics and Space Administration (NASA) supported thiswork through the NASA Cooperative Agreement NCC9-58 with the NationalSpace Biomedical Research Institute.

All rights reserved. No part of this book may be reproduced by any mechanical,photographic or electronic process, or in the form of an audio recording; normay it be stored in a retrieval system, transmitted, or otherwise copied forpublic or private use without prior written permission of the publisher. Black-line masters reproduced for classroom use are excepted.

© 2000 by Baylor College of Medicine

All rights reserved. Published 2000

Printed in the United States of America

ISBN: 1-888997-41-9

ii

What Can We Learn in SpaceAbout Our bodies Here on Earth? iv

Using Cooperative Groups in the Classroom vi

1. What Goes Around . . . 1

2. Living Clocks 6

3. Sleepy Time 11

4. I’ve Got Rhythm 14

5. Shifting Shadows 17

6. Sleeping in Space 20

7. Twenty-Four Hours a Day 24

Table of Contents

iiiFrom Outerspace to Innerspace / Sleep and Daily Rhythms© 2000 Baylor College of Medicine

T here are many reasons to study life sciences in microgravity, from obvious ones such as ensuringastronaut health to less obvious ones such as improving health care on Earth. The human body isdesigned to operate in Earth’s gravity field. When humans are removed from this environment, as when they

travel in space, many complex changes take place: their bones become weaker, fluids shift toward the upper

body, body rhythms are disrupted and motion sickness may occur. Life science research allows us to begin

planning for long-term stays in space and provides important new medical information that may affect the

health care of people here on Earth, such as the ways we care for persons undergoing prolonged bedrest,

or those with osteoporosis.

BALANCE. During their first days in space, astronauts can become dizzy and

nauseated. Eventually they get over it, but once they return to Earth, they have a hard

time walking and standing upright. Finding ways to counteract these changes could

benefit millions of Americans with balance disorders.

BONES. Astronauts’ bones become weak and porous, because the bones are not

working against the Earth’s gravity. Many people on Earth, particularly older women,

also develop weak bones. Space research on bone will help millions of people

with osteoporosis.

CANCER/RADIATION. Outside the Earth’s protective atmosphere, astronauts are

exposed to many kinds of damaging radiation that can lead to cell damage and

increase astronauts’ chances of developing tumors. Learning how to keep astronauts

safe from space radiation may improve cancer treatments for people on Earth.

ivFrom Outerspace to Innerspace / Sleep and Daily Rhythms

© 2000 Baylor College of Medicine

vFrom Outerspace to Innerspace / Sleep and Daily Rhythms© 2000 Baylor College of Medicine

HEART & CIRCULATION. Without gravity, the amount of blood in the body is

reduced. The heart becomes smaller and weaker. This becomes a problem when

astronauts return to Earth. It makes them feel dizzy and weak. Heart failure and

diabetes, experienced by many people on Earth, lead to similar problems.

IMMUNE SYSTEM. It may be easier for astronauts to become sick or develop

diseases by living and working in space. Learning about changes in the astronauts’

blood and immune systems will help us understand many diseases already

here on Earth.

MUSCLES. When muscles do not have to work against gravity, they weaken and

begin to waste away. Special exercises and other strategies to help astronauts’

muscles stay strong in space also may help older and bedridden people, who

experience similar problems on Earth.

SLEEP & WORK. It is hard for astronauts to get enough sleep because the

day/night cycle of Earth is lost and there are many distractions. Strategies to help

astronauts perform without errors also will benefit people such as airline pilots, or

those who must work at night.

TECHNOLOGY. Special systems and equipment, new diagnostic tools and

intelligent computer software that support life science research—as well as

the health of astronauts in space—also will improve diagnosis and care for

patients on Earth.

viFrom Outerspace to Innerspace / Sleep and Daily Rhythms

© 2000 Baylor College of Medicine

Cooperative learning is a systematic way forstudents to work together in groups of two to four. Itprovides an organized setting for group interactionand enables students to share ideas and to learnfrom one another. Students in such an environmentare more likely to take responsibility for their ownlearning. Cooperative groups provide support forreluctant learners,model communitysettings wherecooperation isnecessary, and enablethe teacher to conducthands-on investigationswith fewer materials.

Organization is essentialfor cooperative learningto occur in a hands-onscience classroom.Materials must be managed, investigationsconducted, results recorded, and clean-up directedand carried out. When a class is “doing” science,each student must have a specific role, or chaosmay result.

The Teaming Up! model* provides an efficient systemfor cooperative learning. Four “jobs” are delineated:Principal Investigator, Materials Manager, Reporter and Maintenance Director. Each job entails specificresponsibilities. Students wear job badges thatdescribe their duties. Tasks are rotated within eachgroup for different activities so that each student has

an opportunity toexperience all roles.Teachers even may wantto make class charts tocoordinate job assignments withingroups. For groups with fewer than fourstudents, jobassignments can becombined.

Once a cooperative modelfor learning is established in the classroom, studentsare able to conduct science activities in an organizedand effective manner. All students are aware of theirresponsibilities and are able to contribute tosuccessful group efforts.

Using Cooperative Groups in the Classroom

Principal Investigator● Reads the directions

● Asks the questions

● Checks the work

Maintenance Director● Follows the safety rules

● Directs the clean up

● Asks others to help

Reporter● Writes down observa-

tions and results

● Explains the results

● Tells the teacher whenthe group is finished

Materials Manager● Picks up the materials

● Uses the equipment

● Returns the materials

* Jones, R.M. 1990. Teaming Up! LaPorte, Texas: ITGROUP.

Extension ActivitiesThere are many opportunities for exciting extensionactivities focusing on space travel and its effects on thehuman body. The NASA and NSBRI internet sites

provide a wealth of educational resources that may beuseful in developing such activities. For more infor-mation, go to and .

1From Outerspace to Innerspace / Sleep and Daily Rhythms© 2000 Baylor College of Medicine

CCOONNCCEPTEPTSS● The Earth rotates completely on its axis about every 24 hours.● Cycles of day and night are caused by this rotation and the Earth’s

position relative to the sun.

OOVVEERRVIEWVIEWStudents will make a “mini-globe” to discover what makes day andnight happen on Earth.

SSCCIEIENNCCEE , HE, HE AALLTTH & MH & M AATTH SKILH SKILLL SS● Observing● Measuring● Modeling● Mapping● Drawing conclusions

The Earth rotates at a speed of about1,600 kilometers perhour. Each day on Earth lasts about 24hours, when measuredaccording to theposition of the sun inthe sky. Day lengths aredifferent on otherplanets. One rotationof Mars takes 24.6Earth hours; onerotation of Jupiter is9.9 Earth hours; andone rotation of Venustakes 243 Earth days!

1. What Goes Around . . .Time20 minutes for set-up; 30 minutes to conduct activity

MaterialsEach group will need:● large paper clip● table tennis (ping-pong) or round foam

ball (diameter of 1–2 in.)● flashlight● sheet of cardstock (8 1/2 x 11 in.)● pencils or permanent colored markers● copy of “Spinning Worlds” student sheet● copy of “Day & Night” student sheet

Setup and ManagementBefore the activity, follow the studentinstructions on page 4 and make ademonstration “mini-globe,” using a ball, paper clip, sheet of card stock and markers.

If using table tennis balls, make a smallhole in the bottom of each ball using apush pin before distributing the balls tostudents. For younger students, you alsomay want to straighten the paper clip as directed.

Place the materials for each session in a central area for Materials Managers tocollect for their groups. Have students work in groups.

Procedure1. Challenge students to think about

what causes night and day to happen

BackgroundOur lives and those of other organisms onEarth are shaped in countless ways bythe cycles of day and night. This repeatingpattern of light and darkness is causedby the spinning of our planet and theposition of the sun.

Earth, like other planets in our solarsystem, revolves around the sun in aslightly elliptical orbit. As it does so, theEarth also rotates, or spins, on its axis. It takes about 24 hours for Earth tocomplete one rotation. As students willdiscover through the activities in thisunit, functions of living organisms arelinked to this cycle.

During one 24-hour period, a givenlocation on Earth will experience severalhours of sunlight (day time) followed by aperiod of darkness (night time). Onecomplete rotation equals one day.

As viewed from the North Pole, the Earthspins counterclockwise. This makes thesun appear to come up in the east and toset in the west. In reality, of course, theposition of the sun remains relativelyconstant—while the Earth rotates. Thefollowing activity helps students visualizethis process through the creation of asimple model. The model will helpstudents understand the Earth’s rotationabout its axis and the occurrence of dayand night. It also will demonstrate theslight tilt in the axis of the Earth.

From Outerspace to Innerspace / Sleep and Daily Rhythms© 2000 Baylor College of Medicine

2

The length of day and night changesthroughout the year asa result of the Earth’stilted axis. The axis isthe imaginary line that runs from theNorth Pole through the center of the Earthto the South Pole. If the axis were straightup and down relativeto the sun, all days and nights would be 12 hours longthroughout the year.However, since the axis is slightly tilted,the hemisphere thatleans toward the sun at any given timeexperiences longer days and shorternights. That hemisphere alsoreceives more directrays of light. The combined effect of longer days andmore direct lightcauses the seasonknown as summer.

on Earth. Conduct a discussion andlist students’ ideas on the board.Challenge their thinking by posingquestions such as, Are days andnights always the same length? Is dayalways followed by night? Does thesun shine at night? Why does the sunappear in the east in the morning anddisappear in the west in the evening?If you add the number of hours in aday to the number of hours in thefollowing night, will the sum alwaysequal 24 hours? List any additionalquestions that are posed by students.

2. Tell students that they will be conducting an investigation to helpanswer many of their questions aboutday and night on Earth. Explain thateach group will construct a smallmodel of the Earth and investigatewhat happens when light shines onthe model.

3. Show the students a mini-globe youhave made using a small ball, large

paper clip,sheet of cardstock andmarkers (seedirections onpage 4). Themodel can beas simple or aselaborate asyou choose,depending on

the grade level. Tell students thatthey will be using similar materials to make their models. Distribute theSpinning Worlds directions sheets tostudents and instruct the MaterialsManagers to pick up supplies for theirgroups from a central area.

4. Have students build their modelsfollowing the instructions given onthe “Spinning Worlds” sheet.

5. Once they have completed theirmodels, have students identify whichend of the model Earth represents the North Pole. Next, have themdetermine in which direction themodel Earth must spin if it is torotate in a counterclockwise directionwhen viewed from above the NorthPole. You may need to reviewclockwise and counterclockwise forstudents. Have students stand andface the same direction. Have themturn in place, first clockwise, then counterclockwise.

6. Distributecopies of the “Day &Night” page toeach groupand have them workthrough thequestionsprovided.

Students will create models of the Earth to understand its rotation.


National Space Biomedical Research Institutehttp://www.nsbri.org

Name:You will need:Earth model that you constructed Flashlight

You will use a flashlight to demonstrate how the sun shines toward Earth.1. Hold the flashlight so that it points toward your Earth model

along the marking for 12:00 noon.

2. Color a small dot on the Earth model that represents whereyou live. You will be observing what happens to this dot as theEarth model rotates.

3. Rotate the Earth model counterclockwise until the dot is at 6:00 a.m. This represents early morning in your locality. Notice where the sun (flashlight) is.

Is the dot in the light or in the dark?

Does the light shine directly toward the dot or to one side?

4. Rotate the Earth model 90 degrees (1/4 of a circle) in a counterclockwise direction. Noticewhere the sun (flashlight) is.



5. Rotate the Earth model another 90 degrees (1/4 of a circle). Notice where the sun (flashlight) is.






7. Based on your observations, write a short paragraph below describing why the sun appears overheadat noon, is visible in the western part of the sky in the evening and cannot be seen at midnight.

Activity 1

4 From Outerspace to Innerspace / Sleep and Daily Rhythms© 2000 Baylor College of Medicine


Activity 1

You will need:Table tennis (ping-pong) or foam ball Large paper clip

Sheet of heavy paper or cardstock Colored markers

Make a model of the Earth by following these steps.1. Fold the heavy paper in half twice. This will make four equal sections.

Smooth the sheet and label the folds as shown to the right..

2. Draw a line around the widest part of the ball using a pencil or marker. Thisrepresents the equator on your Earth model.

3. Draw the continents on the ball using the diagrams below as guides. Besure to notice which pole is north and which is south.

4. Straighten one of the loops of the paper clip. Tape the unbent half onto the center point of the folds of the paper.

5. Push the globe over the straightpart of the paper clip, with the North Pole almost facingupward. Your model should look like the drawing to the right.

equator

View of North and South America View of Eurasia and Africa


3

7. Depending on the ages of yourstudents, you also may want todiscuss the effect of the Earth’s tiltedaxis on day length throughout theyear, and on the seasons, asdescribed on page two.

8. Ask students to reconsider each ofthe questions that were asked at the beginning of the activity. Havestudents use their models to providethe answers. Are days and nightsalways the same length? No, for eachlocation, day and night lengths varyaccording to the time of year anddistance from the equator. Is dayalways followed by night? Yes, inmost locations. However, the sun isvisible all the time at the poles duringthe summer season. Does the sunshine at night? Yes, the sun always isshining, even though part of theplanet is in darkness. Similarly, partof Earth always is facing away andshaded from the sun. Why does thesun appear in the east in the morningand disappear in the west in theevening? The direction of rotation ofthe planet makes the sun appear torise in the east and to set in the west. If you add thenumber of hours in a day to thenumber of hours in the following night,will the sum always equal 24 hours?For all locations, except thegeographic north and south poles,each day/night cycle equals about 24 hours.

Extensions● Using information available in the

newspaper, from weather broadcasts or on the Internet, have students keep arecord of the times of sunrise and sunsetfor several weeks for their locality. If pos-sible, compare the information to timesfor a location in the Southern Hemisphere.

● Astronauts in orbit circle the Earthevery 90 minutes. Have students calcu-late the number of day/night cycles thata crew of astronauts might experienceduring a 24-hour period aboard thespace shuttle.

● Challenge students to think aboutwhy portions of the Arctic are referred toas the “Land of the Midnight Sun.” Helpthem understand that, during summer inthe Northern Hemisphere, the North Poleand Arctic regions face toward the sun.This leads to continuous light throughoutthe day and night periods. Have studentsthink about what happens when theSouth Pole and Antarctic regions are tilt-ed toward the sun, and what happens tothese regions during winter months.

● Discuss with students the effect of the Earth’s tilt on the seasons. For exam-ple, when it is winter in the NorthernHemisphere, it is summer in theSouthern Hemisphere. Give students alist of various cities around the world.Have them predict whether residents ofeach city would be experiencing winteror summer in July. Next, have studentsuse a globe to locate each city and verifytheir predictions.

Rotation (turningaround a center point or axis) ismeasured in degrees. A complete rotation is360°. As seen from theNorth Pole, the Earthrotates in acounterclockwisedirection—or fromwest to east.

The commonabbreviation formorning, a.m., comesfrom the Latin antemeridiem, which means “before noon.”The abbreviation, p.m., comes from theLatin post meridiem,meaning “after noon.”



Activity 1

You will need:Table tennis (ping-pong) or foam ball Large paper clip

Sheet of heavy paper or cardstock Colored markers

Make a model of the Earth by following these steps.1. Fold the heavy paper in half twice. This will make four equal sections.

Smooth the sheet and label the folds as shown to the right..

2. Draw a line around the widest part of the ball using a pencil or marker. Thisrepresents the equator on your Earth model.

3. Draw the continents on the ball using the diagrams below as guides. Besure to notice which pole is north and which is south.

4. Straighten one of the loops of the paper clip. Tape the unbent half onto the center point of the folds of the paper.

5. Push the globe over the straightpart of the paper clip, with the North Pole almost facingupward. Your model should look like the drawing to the right.

equator

View of North and South America View of Eurasia and Africa



Name:You will need:Earth model that you constructed Flashlight

You will use a flashlight to demonstrate how the sun shines toward Earth.1. Hold the flashlight so that it points toward your Earth model

along the marking for 12:00 noon.

2. Color a small dot on the Earth model that represents whereyou live. You will be observing what happens to this dot as theEarth model rotates.

3. Rotate the Earth model counterclockwise until the dot is at 6:00 a.m. This represents early morning in your locality. Notice where the sun (flashlight) is.



4. Rotate the Earth model 90 degrees (1/4 of a circle) in a counterclockwise direction. Noticewhere the sun (flashlight) is.









7. Based on your observations, write a short paragraph below describing why the sun appears overheadat noon, is visible in the western part of the sky in the evening and cannot be seen at midnight.

Activity 1

6

CCOONNCCEPTEPTSS● Many activities of living things occur in cycles of about 24 hours.● Daily cycles are governed by internal “clocks.”● Internal clocks are cued by the environment, but run independently.

OOVVEERRVIEWVIEWStudents will observe that some behaviors and functions of living organisms vary predictably every 24 hours.

SSCCIEIENNCCEE , HE, HE AALLTTH & MH & M AATTH SKILH SKILLL SS● Measuring● Observing● Drawing conclusions

In 1729, the Frenchscientist Jean-Jacquesde Mairan was the first to notice that the daily movements of the leaves of certainplants continued even when the plantswere kept in constantdim light. Plants alsohave many otheractivities that varyaccording to the timeof day. These activitiesinclude the opening of flowers, the releaseof fragrances, theopening and closing of pores in the leavesand the regulation offlowering at certaintimes of the year(determined bymonitoring the length of darkness at night).

TimeSeveral 30-minute sessions, dependingon the options selected

MaterialsMaterials will vary, depending on optionsselected.● source of natural sunlight● four bean plants per group (purchase

or grow in small pots from seed)● fluorescent light (portable shop light

or plant “grow light”)● one digital thermometer with several

sterile covers per group● study animals (gerbil, bird, crickets, etc.)

Setup and ManagementStudents should work in cooperativegroups (2–4 students). Conduct discus-sions with the entire class.

Procedure1. Have students work in collaborative

groups to examine one or more of thefollowing examples of daily cycles.

Body temperature.Have studentsmeasure thebody tempera-ture of each ofthe members oftheir group atthree differenttimes duringthe day over

2. Living ClocksBackgroundMost living things behave predictably incycles of about 24 hours, similar to the period of the Earth’s rotation. These cyclesare referred to as circadian, from the Latinwords for “about” (circa) and “day” (dies).

There are many easily recognized behavioral rhythms in nature. Well-knownexamples include the flowering of morning glories at dawn and the hunting routines ofowls at night. These behaviors are governedby internal mechanisms, often referred toas “biological clocks,” within the cells of theliving organisms. When a biological clockruns on a 24-hour cycle, it also can becalled a circadian clock.

Virtually all human body functions are governed by circadian clocks, such as waking and sleeping, body temperature(lower in the morning just after waking,higher in the afternoon), secretion of somehormones, and urine production. Thesechanges occur regularly over intervals of 24hours—without cues from the environment.Researchers once thought that, withoutcues from the environment, the human circadian clock eventually would drift intoa slightly longer cycle of about 25 hours.More recent research has shown, however,that the free-running period of the humanclock is just slightly over 24 hours in bothyoung and older adults.

In this activity, students will explore dailycycles in themselves, animals and plants.



Record the body temperature (temp.) in °F of each member of your group three times each day. For best results, take the first reading just after waking in the morning and the third reading just before going to sleep at night. Wait at least 15 minutes after eating or drinking before you make a measurement.

Activity 2

Dates

Time Temp.Time Temp.Time Temp.Name Time during the day: Evening—just before bedMorning—just after waking

Dates


Dates


Dates


On a separate sheet of paper, calculate the average temperature for each person at each time of day. Graphyour results.



several days. The times should beselected in advance and temperaturestaken at the same time each day. Forexample, just after waking in themorning, eight hours later, and justbefore going to bed in the evening.Students can use a digital thermome-ter under the tongue (being sure to use a clean covering for each measurement) or a thermometer thatthey have at home. Measurementsshould be recorded as degrees F in atable like the one given on page 9.Have students calculate and graphthe average temperature of the group

for each time of day. Ideally, studentsshould make their first measurementjust after waking and before eating or brushing their teeth. Similarly, for other measurements, studentsshould wait at least 15 minutes after eating, drinking or brushingtheir teeth.

What students will observe: body temperature can be as much as 1–2 degrees lower in the very early morning than in the mid to late afternoon. This pattern is relativelyconsistent across individuals.Student results may not show thismuch change due to variations inbody temperature caused by activity.Results also will be affected by theactual times at which temperature is measured.

Plant leaf movement. Grow youngbean plants from seed or purchasethem from a greenhouse. Plantsgrown from seed should have at

least two leaves in addition to the cotyledons (fleshy seed leaves). Placethe plants in a sunny window or in agrowth chamber with a light timer,and have students note the orienta-tion of the larger leaves as early aspossible in the morning and againlater in the afternoon. In particular,students should notice whether theleaves are extended outward orwhether they are folded downward

toward thestem. Havethem repeatthese observa-tions over sev-eral days.Next, place theplants in adarkened corner of theroom or

cupboard, and have students observeand record the position of the leavesat the same times as before.

What students will observe: Leaveswill be dropped toward the stem very early in the day and fullyextended (horizontal) later in the day,regardless of whether the plants

6:00 amBean leaves in the vertical position.

9:00 amBean leaves in the horizontal position.

Other plants showpatterns of leafmovements similar tothose that studentsobserve in beans. Thesensitive mimosa,kelanchoe, and woodsorrel are examples of plants that studentscan investigate.



1. Place bean plants in a sunny window, or under a grow lightwith a timer. Observe the leaves as early as possible in themorning and again later in the afternoon. Notice whether theleaves are facing to the side or facing upward, and draw yourobservations in the spaces below.

Activity 2

Leaves facing to the side.

Leaves facing upward.

Earlymorning

After-noon

Time Time

Day 1

2. Move the bean plants to inside a cupboard or to a dim corner of the room. Make yourobservations as before.

Earlymorning

After-noon

Time Time

Day 3

Earlymorning

After-noon

Time Time

Day 2

3. Describe your observations on a separate sheet of paper.

Earlymorning

After-noon

Time Time

Day 1

Earlymorning

After-noon

Time Time

Day 3

Earlymorning

After-noon

Time Time

Day 2

The famous botanist,Carolus Linneaus,noticed that flowers of some plant speciesopened at predictabletimes of the day. Floral clocks, based on his idea, still areplanted in parks andgardens. Traditionally,the “one o’clock” spotwas planted with roses, “four o’clock”with hyacinths and“midnight,” withpansies.

100

Time 1 Time 2 Time 3

99

98

97

96

x Jimx Mariax Elise

Times of Day

Ave

rage

Bod

yTe

mpe

ratu

re (°

F)

7


actually are exposed to the sun orartificial light.

Note. Students may observe thatplants’ stems curve toward thesource of light. This movement isgoverned by chemicals inside theplant that cause cells on the sideaway from the light to lengthen morethan cells on the side facing the light.This phenomenon is different fromdaily leaf movements, because itresults in permanent changes in theshapes of the stems.

Animal behavior. If you have a hamster, or gerbil, with an exercisewheel in your classroom, have students observe and record thetimes of day when the rodent isactive. Or have students observe andrecord the daily behaviors of otheranimals, such as fish, crickets (willchirp at approximately the same timeeach day) or birds, in the classroom.Students should record eating, resting and active times over severaldays to establish whether there is apredictable pattern to the animals’activities. Best results will beobtained if students make efforts toobserve without disturbing their subjects and if light exposures arekept on a consistent schedule.

2. After students have concluded their investigations, have each group present its observations to the class. Students should be ableto describe the behavior or bodyfunction that they observed, howthey measured the behavior or function (by measuring temperature,

length of time spent on the exercisewheel, etc.) and the pattern or patterns that they discerned.

3. Discuss the results of the differentinvestigations with the class. Askquestions to prompt students’ thinking. What did all of the cyclesthat you observed have in common?Did any of the patterns of behavior orfunction occur without the presence of normal sunlight? Do you think that something other than light is controlling the patterns that wereobserved? Help students reach theconclusion that something insideeach organism controls the observedpatterns. Point out that most organisms have internal timers thatregulate many aspects of their lives.

Extensions● The University of California-San Diego

maintains a web site where students canmonitor the daily behavior of a hamster, as

well as check the hamster's behavior forthe last few days. Have students log on at and participate in the experiment.

Because many body processes are rhythmic, the effectiveness of certain drugs or medicines will varydepending on the time of day.

Other cycles in livingorganisms are longer or shorter than 24hours. Examples oflonger cycles includefluctuation in levels of some human hormones (which vary predictably over several weeks),once-yearly floweringby many plants, andannual migration in a number of animal species. Shorter cycles includethe cardiac cycle (heart beat) and theinternal sleep cycle(stages of sleep).



Record the body temperature (temp.) in °F of each member of your group three times each day. For best results, take the first reading just after waking in the morning and the third reading just before going to sleep at night. Wait at least 15 minutes after eating or drinking before you make a measurement.

Activity 2

Dates


Dates


Dates


Dates


On a separate sheet of paper, calculate the average temperature for each person at each time of day. Graphyour results.



1. Place bean plants in a sunny window, or under a grow lightwith a timer. Observe the leaves as early as possible in themorning and again later in the afternoon. Notice whether theleaves are facing to the side or facing upward, and draw yourobservations in the spaces below.

Activity 2

Leaves facing to the side.

Leaves facing upward.

Earlymorning

After-noon

Time Time

Day 1

2. Move the bean plants to inside a cupboard or to a dim corner of the room. Make yourobservations as before.

Earlymorning

After-noon

Time Time

Day 3

Earlymorning

After-noon

Time Time

Day 2

3. Describe your observations on a separate sheet of paper.

Earlymorning

After-noon

Time Time

Day 1

Earlymorning

After-noon

Time Time

Day 3

Earlymorning

After-noon

Time Time

Day 2


3. Sleepy Time

CCOONNCCEPTEPTSS● All mammals, including humans, and many other kinds of animals

need sleep.● Most people have regular patterns of sleeping and waking.

OOVVEERRVIEWVIEWStudents will collect data about their own sleep patterns and, ifdesired, those of members of their families.

SSCCIEIENNCCEE , HE, HE AALLTTH & MH & M AATTH SKILH SKILLL SS● Observation● Data collection● Graphing● Drawing conclusions● Learning to identify and practice healthy behaviors

Time30 minutes to conduct initial classdiscussion; 3–7 days for students to collectdata on sleep times; 30 minutes fordiscussion of results

MaterialsEach student will need:● log or journal● copies of “Sleeping Patterns Graph”

student sheet

Setup and ManagementBegin the activity with a discussioninvolving the entire class. Workingindividually, students will collect data onthemselves and family members. Theywill share their results with othermembers of their groups.

Procedure1. Challenge students to think about all

the different things that they do everyday. Let each student suggest one ormore activities and create a list on the board.

2. Now ask, What activities could youleave out of this list without affectingyour health or how you feel? Whatactivities must stay on the list? Whydo you think so?

3. Explain to students that they will beexamining one of the essentialactivities on the list—sleep. Encouragestudents to share what they know

BackgroundSleep takes up about one-third of ourlives. All mammals, including humans,and most vertebrates sleep. Many aspectsof sleep still are not understood. Onceviewed as passive shutting-down of most body systems, sleep now isknown to consist of several stages, each with differing levels of brain and muscle activity.

Most of us sleep about the same numberof hours and wake at about the sametime each day, even without an alarm.Many, however, vary their sleep patternsusing external alarm clocks to meet schoolor work schedules. Daily wake-up times inhumans are governed by an internal clock,consisting of about 10,000 nerve cellslocated deep inside the brain. Even withoutany light or sound cues, most people sleepand wake in cycles of close to 24 hours.

Patterns of sleeping and waking vary byage. For instance, newborns sleep 16–18hours each day, including several naps.By age one, children sleep 12–14 hours,including about two naps. Nine or tenhours of sleep, without naps, is normalfor children by age 12. Adults sleep abouteight hours per day. The urge to nap in the afternoon is normal for teenagersand adults, and most override this urge to sleep by remaining active. For somewho may be in a sleep-promoting setting,a nap may occur with possible hazardousconsequences.

All animals restbetween periods ofactivity. Sleep patterns vary amongdifferent animals.Rabbits, for example,sleep for only a fewminutes at a time.Dolphins have a unique form ofsleeping: one half of the dolphin brainsleeps, while the other half continues to be alert and wide awake.

12

about sleep. For instance, when dothey usually sleep, how long do theysleep, what makes them wake?

4. Have each student create a journal,or “Sleep Log,” to record the times heor she goes to sleep and wakes daily.The journal should include: wakingtime; how student felt at waking; howstudent felt during the day (tired, wellrested, etc.); bed time; and howstudent felt at bedtime. If possible,time the activity so that students areable to compare weeknight andweekend sleep patterns. Students maywant to ask other members of theirfamilies to participate and record theirfamily members’ data as well.

5. After 3–5 days, have students graph their data on the “Sleeping Patterns

Graph.” Alsohave studentscalculate theaveragenumber ofhours of sleepreceived byeach personincluded inthe study.

6. Have students share and comparetheir graphs and journals with othermembers of their groups. Help them

look for similarities and differences.Also help the students identifypatterns in their graphs. Askquestions such as, Do most people goto bed and wake up at about the sametime each day? Did you feelparticularly sleepy on any day duringthis activity? Why or why not? Canyou notice anything different about thepart of the graph corresponding to thatday? Who sleeps more—children orgrown-ups? What about very youngchildren—do they have the same sleeppatterns as older children or adults?

Extensions● In addition to recording sleeping and

waking times, also have students recordother essential activities, such as eating orexercising, in their journals.

● Have students investigate the sleeping habits of different kinds ofanimals (Where do they sleep and forhow long?, etc.).

● Have students create a sheet ofpaper with 24 squares by folding it inhalf three times, followed by folding itinto thirds. Have them number thesquares with the hours of the day. Next,ask students to draw the activity thatthey did most during each hour of theday in the corresponding square. Havethem count the number of squares dedicated to sleeping, eating, playing,studying, etc.


Scientists only arebeginning to under-stand why we sleep and what happenswhen we sleep. Sleepconsists of twodifferent phases. Onephase, called non-REMsleep, is characterizedby slow brain activity,no eye movement andlack of muscle tone.Another phase, RapidEye-Movement (REM)sleep, is characterizedby an active brain,bursts of eyemovements, andparalyzed muscles(which makes it safe to dream!).

Dreams are prevalentduring REM sleep.Scientists havedifferent ideas aboutwhy we dream. Somebelieve that the brainconsolidates neededand erases unneededinformation duringdreaming.



Color in the squarerepresenting your bedtime and the squarecorresponding to your wake time for each dayrecorded in yourjournal. Use a differentcolor to fill in thesquares between thebed and wake times.Record days of theweek and hours slept.

Activity 3

Day Day Day Day Day Day Day

Day of Hoursthe Week Slept



Color in the squarerepresenting your bedtime and the squarecorresponding to your wake time for each dayrecorded in yourjournal. Use a differentcolor to fill in thesquares between thebed and wake times.Record days of theweek and hours slept.

Activity 3

Day Day Day Day Day Day Day

Day of Hoursthe Week Slept

Teenagers often have a sleep cycle that is shifted so that their internally programmed sleepingtime ends up beginning aroundmidnight. This maymake it difficult forthem to get enoughsleep if they do notregulate light exposure carefully.

14

A group of nerve cellsthat act as a biologicalclock was first locatedin the brains of housesparrows. Biologicalclocks now have beenidentified in vertebrates,such as mammals,reptiles and someamphibians—and eveninvertebrates, such asfruit flies, cockroaches,crickets and mollusks.“Clocks” also have been found in single-celled organisms, like mold and bacteria.

4. I’ve Got Rhythm

CCOONNCCEPTEPTSS● Sleeping and waking are governed by an internal clock.● The internal “sleep” clock is influenced by external cues.● Changes in schedules can conflict with the body’s internal clock.

OOVVEERRVIEWVIEWStudents will investigate the effects of changing their bedtimes on theirsleep patterns.

SSCCIEIENNCCEE , HE, HE AALLTTH & MH & M AATTH SKILH SKILLL SS● Predicting● Observing● Drawing conclusions

Time30–60 minutes to conduct initial classdiscussion; 30–60 minutes to summarizefindings on the following day

MaterialsEach student will need:● copy of “Sleep Observations” sheet

Setup and ManagementConduct discussions of the activity withthe entire class. Students will carry outtheir own investigations at home andreport back the following day.

ProcedureDay One 1. Remind students of the results of the

previous activities. Did the leaves ofthe bean plants move in the same wayeach day? How about the animals thatwere observed? Did their behaviorshow a daily pattern? Do you also dothings at about the same time eachday? Have students refer to the sleepjournals they created. Do you thinksome of the things you do arecontrolled by an internal clock?

2. Explain to students that they will be investigating their ownbiological clocks for sleeping andwaking. For one night, they willchange their bedtime to one hourearlier than usual, and observewhat happens.

3. Mention the types of observations

BackgroundAs students discovered previously, mostpeople go to sleep and wake up at aboutthe same times each day. This sleep cycleis regulated inside the brain by a group ofnerve cells that govern sleeping andwaking. These cells, which act as a timer,or “biological clock,” stay atuned to theoutside environment by receiving timecues. Sunlight, a strong time cue, isdetected by the retina (the part of the eyethat has receptors for light), which sendsmessages to the brain. Daily exposure tolight keeps the body’s sleep cyclesynchronized to conditions outside.

Abrupt changes in sleeping times, suchas that due to air travel or a change inwork schedule, can cause difficulty withfalling asleep or staying awake, becauseexternal cues conflict with messagesbeing sent by the body’s internal clock.The brain may be signaling sleep, whileoutside conditions may be saying beactive, it’s morning! It can take severaldays to adjust to a new time zone. Otherfactors also can affect the sleep cycle. Forexample, physical exercise, medicines,meal times and stimulants, (such ascaffeine in coffee, tea and soft drinks).

This activity allows students toinvestigate their own internal clocks.Students will try going to bed one hourearlier than usual and observe the effectsthat it has on their abilities to fall asleepimmediately and on their waking timesthe next morning.


15

Astronauts frequentlyhave difficulty sleeping.This may be becausetheir internal clocks are not synchronized to the light conditionsthey experience. Inaddition, the stresses of space flight and hectic work schedulescan affect the quality of astronauts’ sleep.Researchers are looking for ways toaddress these problemsin space. Their resultswill help many peopleon Earth with sleep dis-orders.

that students will make. For example,they should note whether it was easyor hard to fall asleep at the earliertime and whether they woke at theirusual times the next morning.Students also should notice how theyfelt the next day—more sleepy, lesssleepy, etc.

4. Distribute copies of the studentsheets on which students shouldrecord their observations. Explain tostudents thatindividualresults willvary fromperson toperson. Ifpossible, haveeach studentenlist the helpof a parent orolder brotheror sister to record the actual timethat the student falls asleep.

Day Two1. Have students summarize their

observations by writing a shortparagraph about how they felt as theytried to go to sleep at an earlier time.Stimulate their thinking by askingquestions, such as, Was it easier ormore difficult than usual to go to sleepat a new time? Did you notice noisesand other people more or less? Howdid you feel the next morning? Did youwake at your usual time?

2. Have students share their paragraphswith the rest of the class by readingthem aloud or by posting themsomewhere in the classroom. Initiate aclass discussion of the results. Pointout that some students may have had

difficulty falling asleep early becausetheir bodies were used to sleeping at alater time. Likewise, students mayhave woken at their usual times in themorning, even after receiving an extrahour of sleep, because of theprogramming of their internal clocks.

3. You may find that some students feelbetter after receiving the extra sleep.Initiate a discussion of how muchsleep is typically obtained by children(see page 11) and how lack of sleepcan impair performance on bothmental and physical tasks. Forexample, lack of sleep, like alcoholintoxication, can make physical reactions slower.

Extensions● Have students continue with the

earlier bedtimes for several days. Do theyeventually become used to the earliertimes?

● Invite another teacher or a parentwho has traveled across several timezones (across the continental US or toEurope, for example) to talk to the classabout how he or she felt physically forthe first one or two days in the new loca-tion. Was it easy to sleep? Did he or shehave to make adjustments again afterreturning home?

● Invite a policeman, fireman or some-one else who routinely works a nightshift to talk to the class about how he orshe has adapted to the stresses of a noc-turnal work schedule.

● Some animals are more active atnight than during the day. Have studentsinvestigate examples of nocturnal ani-mals (bats, owls, luna moths, etc.) andreport back to the class. What advan-tages might a nocturnal lifestyle have fordifferent kinds of animals?

Sleep disorders affectup to 70 million peoplein the US. Insomnia is asleep disorder whichcauses people to havedifficulty stayingasleep. Apnea is adisorder in whichpeople have difficultybreathing while asleep.



You will need to ask a family member or friend to help with this experiment. You will be going to bed one hour earlier than usual. Write your observations inthe spaces below.

1. What time did you go to bed?

2. What time did you fall asleep? (Have someone write this down for you.)

3. How did you feel when you went to bed early?

4. What time did you wake the next morning?

5. How did you feel the next morning?

6. In class, write a paragraph about your experiment in the space below.

Name

Activity 4

In many places in theUS, everyone sets their clocks ahead one hour in the Springand leaves them thatway until the Fall.Switching to DaylightSavings Time can cause temporaryadjustment problemsfor some peoplebecause their sleepingtimes are changed byone hour.




You will need to ask a family member or friend to help with this experiment. You will be going to bed one hour earlier than usual. Write your observations inthe spaces below.

1. What time did you go to bed?

2. What time did you fall asleep? (Have someone write this down for you.)

3. How did you feel when you went to bed early?

4. What time did you wake the next morning?

5. How did you feel the next morning?

6. In class, write a paragraph about your experiment in the space below.

Name

Activity 4


5. Shifting Shadows

CCOONNCCEPTEPTSS● Time can be measured using the relative positions of the Earth and sun.

OOVVEERRVIEWVIEWStudents will make a sundial (shadow clock) and use it to tell time.

SSCCIEIENNCCEE , HE, HE AALLTTH & MH & M AATTH SKILH SKILLL SS● Measuring ● Locating cardinal directions● Making a model● Observing● Drawing conclusions

Time10 minutes for set-up; two 30–45 minuteperiods to conduct activity

MaterialsEach group will need:● flashlight● paper plate● coffee stirrer● permanent marker● compass

Setup and ManagementPlace the materials in a central area forMaterials Managers to collect for theirgroups. Have students work in groups offour to conduct the activity.

ProcedureDay One 1. Ask students to observe while you use

a flashlight and your hand to make ashadow. Turn the light source off, thenask Where is the shadow? Studentsshould understand that when anobject is in front of a light source, itblocks the light, causing an area ofdarkness—a shadow. Encouragestudents to “play” with light andshadows using the flashlights.

2. Challenge students to think about whathappens to shadows outdoors as theposition of the sun changes relative tothe Earth’s surface. Ask questions suchas, Are shadows always the samesize? Why or why not? When areshadows outside smallest? When are

BackgroundFor a very long time, people relied on theposition of the sun in the sky to estimatethe time of day. Noon or midday wasdesignated as the time when the sun was at its highest point. We now know, of course, that the sun does not moveacross the sky as it appears. Rather, the Earth rotates as it revolves aroundthe sun.

One of the earliest ways of measuringtime used the predictable changes inshadows that occurred as the sun movedacross the sky. Since shadows changepredictably over the course of each day,they can be used to estimate time. A stickplaced vertically in the ground probablywas the first sundial. Simple sundialswere used to tell time in Egypt more than3,000 years ago.

In early times, an hour was calculated as1/12 of the period of daylight. Thus,depending on the time of year, the lengthof the hours in the day varied. Now, wedivide each day into 24 equal hours,which remain unchanged regardless ofthe time of year. Today, time also isstandardized from place to place. Before1884, every locality set its clocks to thehighest position of the sun (=noon). Thisled to considerable confusion, becauseevery town ran on a different time. Now,the world is sectioned into 24 standardtime zones that are uniform. Each timezone accounts for 15 degrees longitudeand 60 minutes of Universal Time.

Over the course ofhistory, different civili-zations explained thecycle of night and dayin different ways. Forexample, some ancientpriests of India believedthe Earth to be sup-ported on 12 hugepillars. At night time,the sun was believed to pass underneath.

Aristotle, a Greekphilosopher, wascertain that the entiresky revolved aroundthe Earth. This Earth-centered view of theuniverse was prevalentin Europe until the16th century.

Copernicus, a Polishclergyman andscientist, is creditedwith providing theworld with a newtheory of the solarsystem, in whichplanets (includingEarth) revolve around the sun.


18

they largest? Can we alwayssee shadows outside? Havestudents think about whetherthere is a pattern to the sizesof shadows made by the sun(shadows are longest in themorning and evening, andshortest at mid-day). Usingflashlights and pencils, havestudents make shadows ofdifferent lengths. Ask them toidentify variables that affectthe length of the shadows.

3. Challenge students to considerwhether there is a pattern to the waythe positions of shadows change overthe course of a day. Do shadows stayin the same place all day? Explain tostudents that they will beinvestigating patterns in shadowmovement. They will be using thepatterns they discover to solve apractical problem: telling time.

4. Distribute copies of the “ShadowClock” sheet to students. Following theinstructions given on the sheet for DayOne, they will work in groups to createShadow Clocks (sundials).

5. Note that if the observations are madeduring normal school hours, theclocks will be calibrated only for aportion of the total day. As analternative, consider having studentsalso calibrate their Shadow Clocks athome, so that the clocks will beuseful for the full range of daylight.

Day Two1. Students will use their Shadow Clocks

in a new location and compare times ofday, as measured by their ShadowClocks, to times shown by a watch orclock. Each group must use a compassto orient their Shadow Clocks in thesame direction as on Day One.

2. After students have completed bothdays’ activities, conduct a discussion

about the accuracy of the ShadowClocks. Ask, How well did yourShadow Clocks measure time, ascompared to a watch or clock? Why doyou think the Shadow Clocks did (ordid not) measure time as accurately asthe other clocks? Also, ask students toconsider when the Shadow Clocksmight not be useful. Examples: night-time (too dark), when skies are cloudy(no shadows), at different times of theyear (shadow pattern will be different,so clocks might not predict timecorrectly), in different locations (pattern will change if other location isat a different latitude).

3. Brainstorm with students on ways to improve the Shadow Clocks. Have them look on the Internet or in the library to find other sundials.

Variations● Have students try using shadow

length to predict the time.● Have students think about why time

zones that account for a one-hour timedifference are separated by 15° of longi-tude.

● Using a globe or an atlas, have stu-dents figure out what time it would be inLondon, Los Angeles, Honolulu andMoscow, if it were 8:00 a.m. in St. Louis,Missouri.

● To learn more about sundials, havestudents check the NASA Web site at.

The position that thesun appears to have inthe sky depends onwhere you are on theEarth’s surface.

In 1972, Universal Time replacedGreenwich Mean Time as the standardreference for tellingtime. Universal Time,also referred to asInternational AtomicTime, is measured byan atomic clock. Theatomic clock uses theextremely regularvibrations that occurwithin atoms tomeasure time.

12noon

1110987654321am

1 2 3 4 5 6 7 8 9 10 11 12mid.

International Date Line(approximately)

Coordinated Universal Time (UTC)formerly Greenwich Mean Time (GMT)

STANDARD TIME

W to Esubtract 24 hours

E to Wadd 24 hours

A sundial based ondrawings from childrenacross the US will travelto Mars aboard NASA'sMars Surveyor 2001lander. Inscribed withthe words “TwoWorlds, One Sun,” thesundial will be 3 inches(about 8 cm ) square,and weigh just over 2ounces (60 grams). Image courtesy of NASA.



Your group will need:Disposable paper plate CompassCoffee stirrer Permanent marker

DAY ONE1. Turn the plate upside down and write the letter

“N” on one edge of the plate to mark the sidethat should face North.

2. With the plate still turned upside-down,make a very small hole in the center usingthe tip of a pencil. Push the coffee stirrerthrough the plate about one-half to oneinch. Put the plate back on the table. Thestirrer should “stand” straight up.

3. Take the plate outside and place it in asunny place.

4. Using the compass, position the plate sothat the “N” is facing North. (If it is windy outside, you may need to tape the plate down).

5. Using the marker, carefully trace the line created by theshadow of the coffee stirrer on the plate and label the time as shown above.

6. At one-hour intervals, repeat steps 4–5.

7. After you have made as many one-hour readings as possible, bring your Shadow Clock back inside.

DAY TWO1. Now you will test the accuracy of your Shadow Clock. Take the clock outside to a new location.

2. Use a compass to position the plate so that the “N” is facing North.

3. Observe where the shadow line falls on the plate. Based on the markings you already have made,estimate the current time as accurately as possible.

4. Compare your estimate to the time as measured by a watch or clock. How close were you?

5. On a separate sheet, describe why the Shadow Clock worked or didn’t work. Does the ShadowClock have any advantages over a mechanical clock? Does it have any disadvantages?

Activity 5

6:00

7:00

8:00

9:00

10:00

11:00 1:00

2:00

3:00

4:00

5:00

6:00

12:00N

Insert coffee stirrervertically into the

center of the paper plate.

Lines that youwill draw each hour

Side view withcoffee stirrer inserted

20

6. Sleeping in Space

CCOONNCCEPTEPTSS● Many different factors affect the quality of sleep.● Astronauts traveling in space experience many disruptions of

normal sleep patterns.

OOVVEERRVIEWVIEWLanguage arts activity in which students brainstorm about when theyhave had difficulty sleeping, read about how astronauts sleep in space,and write about unusual places in which they have slept.

SSCCIEIENNCCEE , HE, HE AALLTTH & MH & M AATTH SKILH SKILLL SS● Identifying common elements● Making extensions to new situations

Time10 minutes for set-up; 30–60 minutes to conduct activity

MaterialsEach student or group of students willneed:● copies of “Catching Zzzzz’s” and “Are

You Sleeping?” student pages

Setup and ManagementConduct this activity with the entire class.Students may read the story, CatchingZzzzz’s, individually, or they make work in teams.

Procedure1. Ask students to remember an

occasion when they had difficultysleeping. Have them share theirexperiences with the rest of the class,and list the experiences on the boardor on an overhead. Scenariossuggested by students might include:the night before an exciting event,such as a birthday party; trying tosleep in the car during a long trip; orbeing wakened by strange orfrightening noises at night.

2. Encourage students to thinkcarefully about the list and toidentify common elements amongthe events. Such elements couldinclude: sleeping in places otherthan home; sleeping before or after unusual events; sleeping whenone’s physical state is not normal

BackgroundMany different factors can affect the qualityof sleep. All of us have had difficultysleeping at one time or another. Excitement,anxiety or stress, consumption ofstimulants, unusual surroundings, noises,travel across time zones, or changes in dailyschedules can make sleeping difficult.Insomnia is the word used to describe anongoing inability to get enough sleep to feelrested during the day. More than 50% ofAmericans suffer from occasional bouts ofinsomnia or other sleep disorders.

Astronauts probably experience moredisruptions of normal sleep patterns thananyone else. The intense work schedule,unusual surroundings, cramped workquarters, stress and excitement of being inspace all can make sleeping difficult. Spacemotion sickness also can contribute tosleeping problems. In addition, the normal24-hour pattern of light and darkness thatprovides a time cue to the body’s internalsleeping and waking cycle is absent.

Since lack of sleep can seriously affectperformance on physical and mental tasks,helping astronauts overcome sleepingproblems is a priority. Several days beforelaunching into space, crew members areexposed to bright lights at specific times, acontrolled environment and programmedmeal periods to help reset their bodies’internal clocks to match the schedules thatwill be followed in space. Research to helpastronauts sleep better also helps people onEarth with similar problems.

Students can do several things to makesure they will be restedand ready to performwell in school.

• Avoid soft drinks orfoods with caffeine(for example,chocolate, some softdrinks, coffee, tea).

• Stick to a regularschedule for going tobed and waking up,and get some brightlight in the morning.

• Get some light exercise in the lateafternoon (but not in the evening before going to bed).

• Recognize that, on average, moststudents need at least nine to tenhours of sleep pernight, and planschedulesaccordingly.


21

(sick with an itchy rash, etc.).

3. Mention tostudents thatthey will be readingabout howastronautssleep inspace. Ask,Do you thinkastronautscan sleep aswell in space as they can at home?What might be different aboutsleeping in space? After studentshave offered their comments,distribute copies of the “Catching Zzzzz’s” and “Are You Sleeping?” pages.

4. Students may read the essay and

complete the reading and writingextensions on their own or by workingtogether in small groups.

5. Provide an opportunity for students to share their work by having them readthe paragraphs that they created aspart of the writing activity on page 23,or by displaying the paragraphssomewhere in class.

Extensions● Have students create drawings to

accompany their paragraphs on sleep-ing.

● Encourage students to accessNASA-associated sites on the WorldWide Web. NASA’s homepage is a goodplace to start .

● Encourage students to find out aboutother occupations in which the sleepingcircumstances might be unusual.

Why do we sleep?Scientists still areinvestigating thisquestion. Some people believe thatsleep helps the bodyrecover from activitiesduring waking hoursand also helps in theformation of memories. Someanimals also mightsleep to save energyduring hours when it is too dark or toodangerous to hunt for food.

Sleeplessnessdiminishes mental andphysical performance.In addition, a sleepybody is moresusceptible to theeffects of drugs andalcohol. Sleepiness can build up day, afterday, after day, creatinga sleep “debt” that may be hard to “pay back.”



Have you ever slept in a sleeping bag? Most people sleep in sleeping bags when they go

camping or when they sleep over at a friend’s house. Astronauts also sleep in sleeping bags when

they are in space.

Each time they sleep on a space craft, astronauts zip themselves into special sleeping bags.

The bags have to be fastened to something, because otherwise the sleeping astronauts would float

around inside the space shuttle, due to the lack of

gravity. Usually, the astronauts are fastened inside

separate sleeping spaces. Each space has a light for

reading and a sliding door that can be closed.

The astronauts can face in any direction when they

are sleeping. Some of the sleeping compartments face

the top of the space shuttle. One of the compartments

faces the floor. Each bed in the compartments is just a

padded board. The astronauts do not need a thick

mattress, because they float freely inside the space

craft and are comfortable in any position.

Astronauts have many things to think about when

they are living and working in space. This can make it

hard to sleep. Astronauts do not experience normal

periods of daylight and night time, either. This also can

make it hard to sleep. Sometimes, part of the crew

sleeps while the other crew members work. If light and sounds make it hard for them to sleep,

the astronauts can wear blindfolds and ear muffs.

Astronauts in their sleeping spaces onshuttle mission STS-68. (NASA photo)

Activity 6




Have you ever slept in a sleeping bag? Most people sleep in sleeping bags when they go

camping or when they sleep over at a friend’s house. Astronauts also sleep in sleeping bags when

they are in space.

Each time they sleep on a space craft, astronauts zip themselves into special sleeping bags.

The bags have to be fastened to something, because otherwise the sleeping astronauts would float

around inside the space shuttle, due to the lack of

gravity. Usually, the astronauts are fastened inside

separate sleeping spaces. Each space has a light for

reading and a sliding door that can be closed.

The astronauts can face in any direction when they

are sleeping. Some of the sleeping compartments face

the top of the space shuttle. One of the compartments

faces the floor. Each bed in the compartments is just a

padded board. The astronauts do not need a thick

mattress, because they float freely inside the space

craft and are comfortable in any position.

Astronauts have many things to think about when

they are living and working in space. This can make it

hard to sleep. Astronauts do not experience normal

periods of daylight and night time, either. This also can

make it hard to sleep. Sometimes, part of the crew

sleeps while the other crew members work. If light and sounds make it hard for them to sleep,

the astronauts can wear blindfolds and ear muffs.

Astronauts in their sleeping spaces onshuttle mission STS-68. (NASA photo)

Activity 6



1. Make a list of the ways in which sleeping in

space is just like sleeping on Earth.

2. Make a list of the ways in which sleeping in

space is different from sleeping on Earth.

Activity 6

3. In the space below or on a separate sheet, write a paragraph about the most unusual place in

which you ever slept. Include answers to the following questions: Where did you sleep? How well

did you sleep? Would you like to sleep there every day?

24

Time10 minutes for set-up; 45 minutes to conduct activity

MaterialsEach student or group will need:● copy of “Tick-Tock, Tick-Tock” sheet● paper to create a poem● markers, crayons, etc., to illustrate

new poem

Setup and ManagementConduct a summary discussion of themajor concepts in the unit by reciting thepoem on page 26 with the class. Studentsshould work independently or in smallgroups for the remainder of the activity.

Procedure1. Review the major concepts to which

students were exposed in this unit, as outlined in the Background sectionof this activity.

2. Read or havestudents readthe poem,Tick-Tock, Tick-Tock. Talk about theconcepts in the poem.

3. Have students create their own

BackgroundCycles and rhythms can be found in allorganisms on Earth. Many of these cyclesare synchronized to the 24-hour cycle ofthe Earth’s rotation about its axis.

The timing of when people are asleep andawake is determined to a large extent byan internal clock. Environmental cues,particularly light, keep the clocksynchronized to external conditions. Theclock itself, however, will continue to runon approximate 24-hour cycles, evenwithout changes in the environment.

The human cycle of sleeping and wakingcan become disrupted if externalconditions, particularly light, change.This happens when travelers move acrosstime zones or when astronauts travel in space.

Space life scientists are looking for waysto help astronauts achieve the sleep theyneed to function well under the stressesof long-term space flight. Their researchalso will help solve sleep-related problemsfor people on Earth.

CCOONNCCEPTEPTSS● Many organisms show daily cycles of activities or functions.● Daily cycles (also called circadian rhythms) are about 24 hours

long—the same as one rotation of the Earth.● Circadian rhythms in living things are controlled by internal

biological clocks that are set to local environmental conditions.● The timing of when humans sleep and wake is governed by an

internal clock.● People can have difficulty sleeping if external conditions change

suddenly and no longer agree with the settings of their internal clocks.

OOVVEERRVIEWVIEWSummative/assessment activity: students will review concepts aboutsleep and daily cycles using a fun poem, and will create their own illustrated rhymes.

SSCCIEIENNCCEE , HE, HE AALLTTH & MH & M AATTH SKILH SKILLL SS● Integrating information● Drawing conclusions

7. Twenty-Four Hours a Day



Tick-tock, Tick-tock, Tick-tock, Tick-tock.Did you know that you are a clock?

Just like the sundial’s shadow-lineyour inside clock can measure time.

It tells you when it’s time to eat,and even when to go to sleep!

But you are not the only onewho know it’s time for work or fun.

The plants can tell it’s time to bloom.They know that springtime’s coming soon!

Most birds at dawn begin to sing —without alarms that ring-a-ling.

Frogs know when to ribbit and croak,to chase some flies, or take a soak!

Barn owls hunt when the day is done.They rarely ever see the sun.

How’d they do it? What can it be?The answer’s in their cells, you see.

People, plants and animals all —have inside clocks that send a call.

The clocks tune in to many cueslike, when it’s dark, it’s time to snooze.

So now you know you are a clock,Shout it out loud: Tick-tock, Tick-tock!

Activity 7



illustrated poems. Several options are possible.• Distribute the poem to students. • After reading the poem, let students

write their own poems on sleep andbiological clocks; or

• Read a few of the verses to getstudents started, and then suggestthat they write verses of their

own to complete the poem; or• Share the first few lines of each

verse and have the studentscomplete the verses with their owninspirations; or

• Devise your own way to inspirestudents to express their knowledgeabout biological rhythms and clocksin verse.



Tick-tock, Tick-tock, Tick-tock, Tick-tock.Did you know that you are a clock?

Just like the sundial’s shadow-lineyour inside clock can measure time.

It tells you when it’s time to eat,and even when to go to sleep!

But you are not the only onewho know it’s time for work or fun.

The plants can tell it’s time to bloom.They know that springtime’s coming soon!

Most birds at dawn begin to sing —without alarms that ring-a-ling.

Frogs know when to ribbit and croak,to chase some flies, or take a soak!

Barn owls hunt when the day is done.They rarely ever see the sun.

How’d they do it? What can it be?The answer’s in their cells, you see.

People, plants and animals all —have inside clocks that send a call.

The clocks tune in to many cueslike, when it’s dark, it’s time to snooze.

So now you know you are a clock,Shout it out loud: Tick-tock, Tick-tock!

Activity 7

Activities Guide for Teachers - University of ArkansasSaundra Saunders, Angi Signorelli, and Marcia...

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Transcript of Activities Guide for Teachers - University of ArkansasSaundra Saunders, Angi Signorelli, and Marcia...