Introduction: Everyone and everything has a shadow. Shadows illustrate how threedimensional
objects can be viewed in two dimensions. Younger students
can learn about the Sun’s relative motion in the sky as they
experiment with shadows.McDonald Observator

McDonald Observatory

University of Texas at Austin

English

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6 STARDAT E /UN I V E R SO TE A CH E R GU I D EEveryone and everything has a shadow. Shadows illustrate how three-dimensional objects can be viewed in two dimensions. Younger stu-dents can learn about the Sun’s relative motion in the sky as theyexperiment with shadows.ACTIVITY ONEBegin by asking, “Where is the Sun at noon?” Depending on the age ofthe child, responses might be “straight up,” “in the sky,” “overhead,” or“in the south.” Ask “What is a shadow?” Accept responses.PREPARATIONDivide the class into teams of two or three before goingoutside.MATERIALS• Chalk• Outdoor drawing area• Lamp• Action figure and flashlightfor each team of studentsEXPERIMENTOne member is to play “statue” — holding still while the other teammembers trace the outlines of both the statue’s feet and shadow on thepavement. When all the tracings are completed, the entire class canexamine them. Wait about 30–60 minutes, then ask the “statues” toreturn to their places (which is why they traced their feet) and hold thesame position again.ANALYSISWhat has changed?ANSWERStudents should notice that the length and position of the shadow havechanged. Younger children may think that the “statue” changed position.Ask them to predict where the shadow will be in three hours. Repeat thetracings about once per hour until the end of the school day. Dependingon the grade, students maymeasure the lengths of theshadows or even graph thelength versus time of day. Dis-cuss the results.ACTIVITY TWOThis activity demonstrates thedaily motion of Earth. We per-ceive the Sun as rising, crossingthe daytime sky, and setting. Itis actually Earth that moves.Shadow PlaySUNWATCHERSUntil well into the last century, one ofthe most important people inthe pueblos of the southwestwas the Sunwatcher. Each day,he watched the Sun rise, using hills orother objects to track its motionalong the horizon. His observationstold the tribe when to plant or har-vest crops, and when to conductimportant ceremonies.The Sunwatchers may have beencarrying on a tradition established bysome of the ancestors of the pueblopeople — the Anasazi, a Navajo namethat means “the ancient ones.” Theybuilt a large, well-ordered civilizationin the Four Corners region a millenni-um ago.Archaeological sites at severalAnasazi villages suggest that theywatched the Sun carefully. One exam-ple is the Sun room in HovenweepCastle, a ruin in southeastern Utah.Doorways and windows in the roomalign with the sunset on the summerand winter solstices — when the Sunappears farthest north and south inthe sky — and the equinoxes, whenit’s half-way between.Nearby, a pair of buildings atopCajon Mesa apparently served as asolar calendar. Sunwatchers kept trackof the Sun’s motion from a series ofwindows.They also used the shadowsof the two buildings to determine thearrival of the solstices and equinoxes.The most famous Anasazi sunwatch-ing sites are in Chaco Canyon, innorthwestern New Mexico. In fact,quite a few people are visiting thecanyon this week to watch the sunriseon the summer solstice. More on thattomorrow.STARDAT E /UN I V E R SO TE A CH E R GU I D E 7PREPARATIONInside the classroom, arrange all the children in a circle around a lamp,which represents the Sun. The teacher should demonstrate and then askthe children to “spin.” (Young children prefer the term “spin” to “rotate”when thinking about Earth’s motion.)DEMONSTRATIONTo find the proper direction, place your right hand over your heart (theposition for reciting the Pledge of Allegiance) and rotate in the directionthe fingers point. (As an extension, walk around the lamp to modelEarth’s annual motion around the Sun. Don’t try to spin and walk at thesame time; it takes 365.25 spins to make a year!)ANALYSISWhat has changed?ANSWERWhen children are facing the lamp, it is day. When they are facing awayfrom the lamp, it is night.ACTIVITY THREEPREPARATIONReplicate the outdoor activity in the classroomby placing an “action figure” (a 3-inch figureworks well) on a piece of paper. Use a flashlightto represent the Sun in the darkened room.EXPERIMENTMove the “Sun” across the sky, from rising inthe east to setting in the west, through a curvedpath over the paper.ANALYSISWhat changes?ANSWERThe position of the flashlight mimics the dailyapparent motion of the Sun as Earth rotates. EXTENSIONStudents draw pictures of why we have day and night.Students study how ancient people created stories about what causes dayand night.NATIONAL SCIENCE EDUCATION STANDARDS• Content Standard in K-4 EarthScience (Objects in the sky,changes in Earth and sky)• Content Standard in K-4 Scienceas Inquiry (Abilities necessary todo scientific inquiry)EWFlashlightTIM JONES (3)© April 2011          The University of Texas at Austin Shadow Play Subjects: Our Solar System  Grade Levels: K-5  Everyone and everything has a shadow. Shadows illustrate how three-dimensional objects can be viewed in two dimensions. Younger students can learn about the Sun’s relative motion in the sky as they experiment with shadows.  Texas Essential Knowledge and Skills Science: §112.11 kindergarten (b)-6(A) use the five senses to explore different forms of energy such as light, heat, and sound.  §112.11. kindergarten (b)-8(B) identify events that have repeating patterns, including seasons of the year and day and night.  §112.12. grade 1(b)-2(D) record and organize data using pictures, numbers, and words. §112.12. grade 1 (b)-2(E) communicate observations and provide reasons for explanations using student-generated data from simple descriptive investigations. §112.12 grade 1 (b)-(8)(B) observe and record changes in the appearance of objects in the sky such as clouds, the Moon, and stars, including the Sun.  §112.12 grade 1 (b)-8(C) identify characteristics of the seasons of the year and day and night. §112.13 grade 2 (b)-8(D) observe, describe, and record patterns of [caused by] objects in the sky, including [shadows and] the appearance of the Moon.  §112.14 grade 3 (b)-3(C) represent the natural world using models such as volcanoes or Sun, Earth, and Moon system and identify their limitations, including size, properties, and materials.  §112.14 grade 3 (b)-8(C) construct models that demonstrate the relationship of the Sun, Earth, and Moon, including orbits and positions.  §112.15 grade 4 (b)-8(C) collect and analyze data to identify sequences and predict patterns of change in shadows, tides, seasons, [in the reflection of sunlight,] and [in] the observable appearance of the Moon over time.  §112.16 grade 5 (b)-8(C) demonstrate that Earth rotates on its axis once approximately every 24 hours causing the day/night cycle and the apparent movement of the Sun across the sky.  

Shadow Play

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