Using a Sundial

by Nancy P. Moreno, Ph.D. Barbara Z. Tharp, M.S. Gregory L. Vogt, Ed.D.

RESOURCES For online presentations of each activity and downloadable slide sets for classroom use, visit http://www.bioedonline.org or http://www.k8science.org.

© 2012 by Baylor College of Medicine © 2012 by Baylor College of Medicine SOURCE URLs All rights reserved. BAYLOR COLLEGE OF MEDICINE Printed in the United States of America, Second Edition. BIOED ONLINE / K8 SCIENCE www.bioedonline.org / www.k8science.org ISBN-13: 978-1-888997-58-3 CENTER FOR EDUCATIONAL OUTREACH www.bcm.edu/edoutreach

Teacher Resources from the Center for Educational Outreach at Baylor College of Medicine. HARVARD UNIVERSITY The mark “BioEd” is a service mark of Baylor College of Medicine. HEALTHY SLEEP http://healthysleep.med.harvard.edu The information contained in this publication is intended solely to provide broad consumer understanding and knowledge of health care topics. This information is for educational pur- INDIANA UNIVERSITY poses only and should in no way be taken to be the provision or practice of medical, nursing or PLANTS-IN-MOTION professional health care advice or services. The information should not be considered complete and http://plantsinmotion.bio.indiana.edu should not be used in place of a visit, call or consultation with a physician or other health care provider, or the advice thereof. The information obtained from this publication is not exhaustive and does ITOUCHMAP.COM not cover all diseases, ailments, physical conditions or their treatments. Call or see a physician or www.itouchmap.com other health care provider promptly for any health care-related questions. MEDLINE PLUS The activities described in this book are intended for school-age children under direct supervision of http://medlineplus.gov adults. The authors, Baylor College of Medicine (BCM) and the National Space Biomedical Research ( ) Institute NSBRI cannot be responsible for any accidents or injuries that may result from conduct NATIONAL AERONAUTICS AND SPACE of the activities, from not specifically following directions, or from ignoring cautions contained in the ADMINISTRATION (NASA) text. The opinions, findings and conclusions expressed in NASA ASTRONOMY PICTURE OF THE DAY this publication are solely those of the authors and do not necessarily reflect the views of http://antwrp.gsfc.nasa.gov/apod BCM, NSBRI or the National Aeronautics and Space Administration (NASA). Cover: Illustrations of moon, clock, sun, world and waking female © Adobe, Inc. Illustrations NASA CONNECT™ of globe model with flashlight and graphs by M.S. Young; protractor by G.L. Vogt from http://connect.larc.nasa.gov Space Educator’s Handbook, NASA Johnson Space Center. Photographs of girl with clock face, girl holding globe and sleeping student © PunchStock. Image of astronauts courtesy of NASA. NASA JOHNSON SPACE CENTER Space Educator’s Handbook Authors: Nancy P. Moreno, Ph.D., Barbara Z. Tharp, M.S., and Gregory L. Vogt, Ed.D. http://er.jsc.nasa.gov/SEH/sundialn.pdf Senior Editor: James P. Denk, M.A. Creative Director and Editor: Martha S. Young, B.F.A. NASA IMAGES www.nasaimages.org ACKNOWLEDGMENTS The authors gratefully acknowledge the support of Bobby R. Alford, M.D., Jeffrey P. Sutton, M.D., Ph.D., William A. Thomson, Ph.D., Laurence R. Young, Sc.D., Jeanne L. Becker, Ph.D., and Kathy NATIONAL HEART, LUNG AND BLOOD Major, B.A., as well as the contributions of the following science reviewers: Mary A. Carskadon, INSTITUTE, NATIONAL INSTITUTES OF HEALTH www.nhlbi.nih.gov 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. NATIONAL OCEANIC AND ATMOSPHERIC We especially thank Siobhan Banks, Ph.D., and Daniel Mollicone, Ph.D., the science reviewers for this ADMINISTRATION (NOAA) revised and updated version of the guide. Preparation of this guide would not have been possible NATIONAL GEOPHYSICAL DATA CENTER without the invaluable assistance of the following field test teachers: Yolanda Adams, Jeri Alloway, www.ngdc.noaa.gov/geomagmodels/Declination.jsp Vivian Ashley, Susan Babac, Henrietta Barrera, Paula Clark, Carol Daniels, Barbara Foreman, Carolyn Hopper, Susan King-Martin, Mary Helen Kirby, Sue Klein, Jacqueline McMahon, Sandra Prill, Carol NATIONAL UNDERSEA RESEARCH PROGRAM Reams, Mary Ellen Reid, Saundra Saunders, Angi Signorelli, and Marcia Wutke. www.nurp.noaa.gov

This work was supported by National Space Biomedical Research Institute through NASA SUNRISE/SUNSET CALCULATOR NCC 9-58. www.srrb.noaa.gov/highlights/sunrise/sunrise.html No part of this book may be reproduced by any mechanical, photographic or electronic process, or in the form of an audio recording; nor may it be stored in a retrieval system, transmitted, or otherwise NATIONAL RESEARCH COUNCIL copied for public or private use without prior written permission of the publisher. Black-line masters NATIONAL SCIENCE EDUCATION STANDARDS reproduced for classroom use are excepted. www.nap.edu/openbook.php?record_id=4962

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WIKIMEDIA COMMONS http://commons.wikimedia.org A UniquE Partnership: NASA and thE NSBRI TEaming witH bEnEfits by Jeffrey P. Sutton, M.D., Ph.D., Director, National Space Biomedical Research Institute (NSBRI)

pace is a collaborations and revolutionary help guide the Institute in achieving Schallenging research advances that result from its goals and objectives. environment for them is enormous and unprec- It will become necessary to the human body. edented, with substantial benefits perform more investigations in the With long-duration for both the space program and the unique environment of space. The missions, the American people. vision of using extended exposure physical and Through our strategic plan, the to microgravity as a laboratory for psychological NSBRI takes a leadership role discovery and exploration builds stresses and risks to Dr. Jeffrey P. Sutton in countermeasure development upon the legacy of NASA and our astronauts are significant. Finding and space life sciences education. quest to push the frontier of human answers to these health concerns is The results-oriented research and understanding about nature and at the heart of the National Space development program is integrated ourselves. Biomedical Research Institute’s and implemented using focused The NSBRI is maturing in an program. In turn, the Institute’s teams, with scientific and manage- era of unparalleled scientific and research is helping to enhance ment directives that are innova- technological advancement and medical care on Earth. tive and dynamic. An active Board opportunity. We are excited by the The NSBRI, a unique partner- of Directors, External Advisory challenges confronting us, and by ship between NASA and the aca- Council, Board of Scientific our collective ability to enhance demic and industrial communities, Counselors, User Panel, Industry human health and well-being is advancing biomedical research Forum and academic Consortium in space, and on Earth. with the goal of ensuring a safe and productive long-term human NSBRI RESEARCH AREAS presence in space. By developing CARDIOVASCULAR PROBLEMS group behavioral health during flight and post flight. new approaches and countermea- The amount of blood in the body is reduced when astro- People on Earth can benefit from relevant assessment sures to prevent, minimize and nauts are in microgravity. The heart grows smaller and tests, monitoring and intervention. weaker, which makes astronauts feel dizzy and weak RADIATION EFFECTS AND CANCER reverse critical risks to health, when they return to Earth. Heart failure and diabetes, Exploration missions will expose astronauts to greater the Institute plays an essential, experienced by many people on Earth, lead to similar levels and more varied types of radiation. Radiation problems. enabling role for NASA. The exposure can lead to many health problems, including NSBRI bridges the research, tech- HUMAN FACTORS AND PERFORMANCE acute effects such as nausea, vomiting, fatigue, skin nological and clinical expertise of Many factors can impact an astronaut’s ability to injury and changes to white blood cell counts and the work well in space or on the lunar surface. NSBRI is immune system. Longer-term effects include damage the biomedical community with studying ways to improve daily living and keep crew- to the eyes, gastrointestinal system, lungs and central the scientific, engineering and members healthy, productive and safe during explora- nervous system, and increased cancer risk. Learning operational expertise of NASA. tion missions. Efforts focus on reducing performance how to keep astronauts safe from radiation may With nearly 60 science, tech- errors, improving nutrition, examining ways to improve improve cancer treatments for people on Earth. sleep and scheduling of work shifts, and studying SENSORIMOTOR AND BALANCE ISSUES nology and education projects, how specific types of lighting in the craft and habitat During their first days in space, astronauts can the NSBRI engages investigators can improve alertness and performance. become dizzy and nauseous. Eventually they adjust, at leading institutions across the MUSCLE AND BONE LOSS but once they return to Earth, they have a hard time nation to conduct goal-directed, When muscles and bones do not have to work walking and standing upright. Finding ways to counter- peer-reviewed research in a team against gravity, they weaken and begin to waste away. act these effects could benefit millions of Americans Special exercises and other strategies to help astro- with balance disorders. approach. Key working relation- nauts’ bones and muscles stay strong in space also SMART MEDICAL SYSTEMS AND TECHNOLOGY ships have been established with may help older and bedridden people, who experience Since astronauts on long-duration missions will not be similar problems on Earth, as well as people whose end users, including astronauts able to return quickly to Earth, new methods of remote work requires intense physical exertion, like firefighters and flight surgeons at Johnson medical diagnosis and treatment are necessary. These and construction workers. Space Center, NASA scientists systems must be small, low-power, noninvasive and and engineers, other federal NEUROBEHAVIORAL AND STRESS FACTORS versatile. Portable medical care systems that monitor, To ensure astronaut readiness for space flight, diagnose and treat major illness and trauma during agencies, industry and interna- preflight prevention programs are being developed flight will have immediate benefits to medical care tional partners. The value of these to avoid as many risks as possible to individual and on Earth.

For current, in-depth information on NSBRI’s cutting-edge research and innovative technologies, visit www.nsbri.org. Teaming With Benefits © 2012 Baylor College of Medicine The Science of Sleep and Daily Rhythms iii BioEd Online | K8 Science OVERVIEW It is possible to measure time via the relative positions of Earth and the sun. Students make a sundial (shadow clock) appropriate for their geographic location in the northern hemisphere and use it to tell time.

Activity Us ing a Su n d ia l

or centuries, people relied on the shadows to tell time in Egypt more than Fposition of the sun in the sky to esti- 3,000 years ago. mate the time of day. Noon or midday When humans first began keeping was designated as the time when the sun track of time, an hour was calculated as Apparent Time was at its highest point in the sky. We now 1/12 of the period of daylight on any given The sun’s apparent position know, of course, that the sun does not day. Thus, the length of an hour varied in the sky depends on your move across the sky. Rather, Earth rotates with the seasons. Now, we divide each location on Earth’s surface, as it revolves around the sun. day into 24 equal hours, which remain the day of the year, and the One of the earliest tools used to mea- unchanged regardless of the time of year. time of day. sure time was the movement of shadows In modern society, time also is standard- on the ground over the course of a day. ized from place to place. Before 1884, Since shadows move the same way each every town set its clocks to the highest Teacher Resources day, they can be used to estimate time. position of the sun (noon). As a result,

Simple sundials—perhaps only a stick each town ran on a different time, and placed vertically in the ground—used there was great confusion. Today, the world is sectioned into 24 standard, uni- SCIENCE EDUCATION CONTENT STANDARDS* form time zones. Each time zone accounts GRADES 6-12 for 15 degrees longitude and 60 minutes of Universal Time. PHYSICAL SCIENCE • The motion of an object can be described by its

position, direction of motion and speed. That TIME motion can be represented and measured on a 10 minutes for setup; two 30–45 minute Downloadable activities graph. periods to conduct activity in PDF format, annotated • The sun is a major source of energy for changes on Earth’s surface. The sun’s energy arrives as slide sets for classroom light. MATERIALS use, and other resources EARTH AND SPACE SCIENCE Teacher (see Setup) are available free at • The sun, an average star, is the central and larg- • 24 sheets of white cardstock www.BioEdOnline.org or est body in the solar system. • Flashlight www.k8science.org. • Most objects in the solar system are in regular Globe or map with latitude markings and predictable motion. • Sundial template SCIENCE, HEALTH & MATH SKILLS • • Measuring Each group of students will need: • Locating cardinal directions • Flashlight • Making a model Hole punch • Observing • Magnetic compass • Drawing conclusions • Each student will need: * National Research Council. 1996. National Science Education Standards. Washington, D.C., National Academies Press. • Fine-tip ballpoint pen • Opaque drinking straw

Any location on Earth can be pinpointed using the imaginary lines of latitude and longitude. Universal Time Both measurements are described in degrees. Each degree is divided into 60 minutes, and each minute is divided into 60 seconds. Image © Cartesia MapArt. In 1972, Universal Time replaced Greenwich Mean Latitude is measured with parallel imaginary lines Time as the standard that circle Earth, both north and south of the equator reference for telling time. (which has a latitude of 0°). In addition to the Universal Time, also known equator, there are four key lines of latitude related as International Atomic to the relative positions of Earth and the sun. Time, is measured by an • Arctic Circle: 66° 33’ 39” N (read as atomic clock, which uses 66 degrees, 33 minutes, 39 seconds) the extremely regular vibra- • Tropic of Cancer: 23° 26’ 21” N tions that occur within • Tropic of Capricorn: 23° 26’ 21” S atoms to measure time. • Antarctic Circle: 66° 33’ 39” S

At latitudes between the Tropics, the sun may be Meridians seen directly overhead at noon on the June solstice (in the northern hemisphere) or December The imaginary great circles solstice (in the southern hemisphere). North of the Arctic Circle and south of the Antarctic Circle, passing through the the sun is visible for 24 continuous hours at least one day per year. North and South Poles are Longitude describes east-west position, as measured from the prime meridian in England referred to as lines of (which has a longitude of 0°). Lines of longitude extend between Earth’s North and South Poles. longitude, or meridians. Longitudes are measured from 0° to 180° east and 180° west (or -180°). Both 180-degree longitudes share the same line, in the middle of the Pacific Ocean. It takes Earth one hour to rotate Parallels 15°, which is why the 24 time zones are separated by 15° of longitude. Circles or lines of latitude sometimes are referred to • Pencil that an object in front of a light source as parallels, because they • Pair of scissors blocks the light, causing an area of are parallel to one another. • Ruler (12-in.) darkness—a shadow. Encourage stu- • Several pieces of clear tape (each dents to create different shadows using about 2–3 in. in length) their flashlights. • Copy of student sheet 2. Challenge students to envision what • Prepared copy of sundial on happens to shadows outdoors as the cardstock position of the sun changes, relative to the Earth’s surface. Ask, Are shadows SETUP & MANAGEMENT always the same size? Why or why not? When are Make 24 copies of the sundial template the shadows we see outside smallest? When are on cardstock. Place materials in a central they largest? Can we always see shadows outside? area for materials managers to collect. Ask students if there is a predictable Students should work in groups of four to pattern to the different sizes of shad- share materials, but each student should ows made by the sun (shadows are construct his/her own sundial. longest in the morning and evening, and shortest at midday). Using flash- PROCEDURE lights and pencils, have students make 1. Have students observe while you shadows of different lengths. Ask them darken the room and use a flashlight to identify variables that affect shadow to make a shadow of your hand. Then length (for example, height of pencil turn flashlight off, and ask, Where is the and angle of light). shadow? Students should understand Continued

© 2012 Baylor College of Medicine Using a Sundial BioEd Online | K8 Science 2 The Science of Sleep and Daily Rhythms © Tunç Tezel, The World at Nigh N his all-sky composite image taken in TBursa, Turkey, shows the daily trail of Finding Latitude the sun in three strings, sunrise-to-sunset, and Longitude during the summer solstice (June, top string), the vernal equinox (March, middle The Internet is a good t . string), and the winter solstice (December, resource to find latitude bottom string). The sun’s path is about the and longitude calculators. same for both the vernal equinox and autum- One such website, iTouch- nal equinox (September). Map.com, will provide North is at the top of the image. The point coordinates of any street where the “X” shaped lines intersect is address in degrees, min- Bursa’s longitude projected in the sky. (Hold utes and seconds. To find the picture over your head to see why.) the latitude and longitude S Download a larger version of the image of any given address, or to from NASA’s Astronomy Picture of the Day access other features, go website (http://antwrp.gsfc.nasa.gov/apod/ap080922.html) for use with this activity’s first to http://itouchmap.com/. Extension (below). Magnetic 3. Explain to students that they will be 7. Conduct a class discussion or have Declination investigating and using patterns in students write about the accuracy of shadow movement to solve a practical their sundials. Ask, How well did your Magnetic declination is the problem: how to tell time. sundial measure time, compared to a watch or angle between the local 4. Distribute copies of the student sheet. clock? Why do you think your sundial did (or did magnetic field—the direc- Students will need to know the lati- not) measure time as accurately as other clocks tion pointed by the north tude of their location to build their do? Also, ask students to consider if end of a compass—and sundials properly. Use a globe there are times a sundial might not geographic north. You or map, or have students find this be useful. Examples: nighttime (too can find your magnetic information on the Internet. dark); or when skies are cloudy (no declination at the National 5. Have students test their sundials by shadows). Geophysical Data Center’s placing the dials outside on the (NGDC) website, www. ground, with the gnomon (part of the EXTENSIONS ngdc.noaa.gov/geomag- sundial that casts the shadow) pointed • Using a copy of the image above, models/Declination.jsp. directly north. To obtain a more have students draw the lines as shown. To correct the reading accurate reading, students should use The mid-point is Bursa’s longitude line given by the magnetic a magnetic compass to orient their projected in the sky. Have students start compass, add or subtract sundials toward the north. They also from the “east,” and count the number the appropriate number of can check and correct for the mag- of hours of daylight for each string. Ask, degrees from your read- netic declination where they live, to Which season does each string represent? During ing. The NGDC website ensure that their sundials are pointed which season is the sun higher in the sky? Lower? displays a map with the toward “true north,” (see “Magnetic What do these observations tell us about Earth’s appropriate correction. Declination, sidebar, right). seasons? 6. Once the sundial’s gnomon is pointing in • Have students try using shadow length the correct direction, students should to tell the time. locate where the sun’s shadow crosses • Have students think about why time the dial and estimate the time, based zones, each of which accounts for a one- on their reading. Then, have students hour time difference, are separated by compare the time indicated by their 15° of longitude. sundials to actual “clock time.” If day- • Have students figure out what time light savings time is in effect, subtract it is in other parts of the world when it one hour from the “sundial time.” is 8:00 am in their own location.

Using a Sundial © 2012 Baylor College of Medicine The Science of Sleep and Daily Rhythms 3 BioEd Online | K8 Science Base NASA Johnson Space Center. NASA Johnson Space Center. Space Educator’s Handbook, Space Educator’s Adapted by G.L. Vogt from the Adapted by G.L.

Your teacher will give you a piece of cardstock with a sundial pattern printed on it. You also will need a 12-inch ruler, a pair of scissors, a fine-tip ballpoint pen, a hole punch, one opaque drinking straw, clear tape and a magnetic compass.

Instructions Rays of the sun

1. Cut the pattern on the solid lines, as indicated. Extend the cuts to the edges of the paper. Do not cut Latitude protractor flap the dashed lines.

Latitude 2. Using a ruler and a fine-tip ballpoint pen, score the protractor flap dashed “fold lines.” (Press the pen point into the paper while tracing along the edge of the ruler. This forms a groove that enables a straight fold.) Score and fold on the 3. Determine the latitude of your location by searching latitude line for your city name and latitude on the Internet, or by of your location checking a map or globe. Base

4. Score the lines on each latitude protractor that are Face nearest the latitude of your location.

5. Fold the paper along all the scored lines. Fold the sundial rectangle and the latitude protractor flaps backward. Fold the lower corner of the latitude pro- Base tractors upward along the angle line for your latitude (the latitude shown in the example is 30°). Gnomon 6. Tape the corners of the latitude flaps to the base.

7. Use a hole punch to make a hole in the circle on the face of the sundial. About 3 in. from Adapted by M.S. Young and G.L. Vogt from the 8. Slip a straw through the hole and bend the straw the end about three inches from the inside end, as shown to the right. The end of the straw sticking out from the face of the sundial is called a gnomon (noh-mon). Tilt the gnomon so that it is perpendicular (at a 90° angle) to the face of the sundial. Use tape to anchor the folded end of the straw to the base. Also, tape the Base straw to the back of the sundial so that the gnomon can’t slip. Space Educator’s Handbook, Using the Sundial

1. Place the dial on the ground and point the gnomon directly north. If you use a magnetic compass to determine north, be sure to check and correct for the magnetic declination where you live. Magnetic declination is the

difference between magnetic north and true north for your location. You can find your magnetic declination at NASA Johnson Space Center. the following site: http://www.ngdc.noaa.gov/geomagmodels/Declination.jsp.

2. Once your sundial’s gnomon is pointing in the correct direction, locate where the sun’s shadow crosses the dial and estimate the time. If daylight savings time is in effect, subtract one hour from your sundial’s time.