Within Concept Change
What A Private Universe Revealed
The seasons-and-moon-phase interviews show how confident learners can retain private explanations after years of instruction.
On this page
- The astronomy answers that exposed private models
- Why traditional instruction missed the problem
- Lessons for teaching seasons and moon phases
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Introduction
When the documentary A Private Universe appeared in the late 1980s, it became one of the most influential pieces of evidence in science education. Its central finding was unsettling: students who had successfully completed years of science classes, including some graduating from Harvard University, often could not correctly explain basic astronomical phenomena such as the seasons or the phases of the Moon. More importantly, they were not simply forgetting facts. They had built coherent private explanations that seemed sensible to them and remained intact despite formal instruction. [Annenberg Learner]learner.orgAnnenberg LearnerA Private UniverseInterviews are held with high school students and Ivy League graduates asking them to explain what cau… [Center for Astrophysics]lweb.cfa.harvard.eduCenter for AstrophysicsCfA Education and Outreach — K-12 Professional DevelopmentA Private Universe (1987) is an award-winning short docu…
The documentary became a landmark example in conceptual change research because it showed that science learning is not just about receiving information. Learners can memorise correct answers for tests while continuing to reason with older explanatory models. Astronomy proved especially revealing because many everyday observations appear to support intuitive but incorrect explanations. [Annenberg Learner]learner.orgAnnenberg LearnerA Private UniverseInterviews are held with high school students and Ivy League graduates asking them to explain what cau… [ScienceDirect]sciencedirect.comScienceDirectThe impact of teaching on students' definitions and…by E Kikas · 1998 · Cited by 188 — This longitudinal investigation wa…
What the interviews exposed
The most memorable scenes in A Private Universe involve interviewees being asked simple questions: Why is it warmer in summer than in winter? What causes the Moon’s phases?
Many respondents confidently answered that summer occurs because Earth is closer to the Sun and winter occurs because Earth is farther away. Others struggled to explain why opposite seasons occur simultaneously in the Northern and Southern Hemispheres. Several participants drew highly distorted orbits to justify their reasoning. [Annenberg Learner]learner.orgAnnenberg LearnerA Private UniverseInterviews are held with high school students and Ivy League graduates asking them to explain what cau… [UBC]blogs.ubc.caconceptualizing misconceptionsUBC BlogsConceptualizing Misconceptions – STEM12 Jan 2017 — “Relating back to Heather, one of her large misconceptions was her figure eig…
The Moon-phase interviews revealed similarly persistent misconceptions. Interviewees often claimed that the phases are produced by Earth’s shadow falling across the Moon, effectively confusing ordinary lunar phases with lunar eclipses. Some invoked clouds or atmospheric effects rather than the changing geometry between the Sun, Earth and Moon. [scienceinschool.org]scienceinschool.orgA Private Universe online resources, By Matthew H…7 Dec 2010 — The film also mentions another aspect in which misconceptions prevail o… [LPI]lpi.usra.eduLPIPhasesMisconceptionsMoon Phases: Misconceptions and Educational Research. Common misconceptions include: The Moon can only be seen at…
What made these answers important was not that they were wrong. Students frequently gave detailed explanations, drew diagrams and defended their reasoning. Their responses demonstrated that they possessed functioning mental models rather than isolated factual errors. The documentary’s title referred to these internally consistent but scientifically inaccurate frameworks: each learner carried a “private universe” of explanations. [Annenberg Learner]learner.orgAnnenberg LearnerA Private UniverseInterviews are held with high school students and Ivy League graduates asking them to explain what cau… [SIU School of Medicine]siumed.eduSIU School of MedicineA Private UniverseInterviews are held with high school students and Ivy League graduates asking them to explain wha…
The seasons misconception looked reasonable
The seasons example became particularly famous because the incorrect explanation appears so intuitive.
In everyday life, moving closer to a heat source makes things warmer. If a radiator, campfire or lamp feels hotter when approached, it seems reasonable to assume that Earth’s temperature depends mainly on its distance from the Sun. The problem is that seasonal temperature differences are dominated by Earth’s axial tilt, which changes sunlight angle and day length. Distance plays only a minor role. In fact, Earth is slightly closer to the Sun during Northern Hemisphere winter than during Northern Hemisphere summer. LPI [The Christian Science Monitor]csmonitor.comSeasons are caused by Earth s distance from the sunThe Christian Science MonitorSeasons are caused by Earth's distance from the sun31 Oct 2013 — A sensible explanation for the seasons is t…
Research conducted long after the documentary continued to find the same misconception among secondary students, university students and trainee teachers. Studies repeatedly report explanations based on changing Earth–Sun distance, altered tilt direction or confusion between daily and yearly motions. [Eurasia Journal]ejmste.comEurasia Journalalternative-conceptions-of-astronomy-how-irish-secondaryMarch 18, 2021 — by A Cardinot · 2021 · Cited by 20 — seasons as a results of the Earth's distance to the Sun, underestimation of spatio… [ScienceDirect]sciencedirect.comApparent movement of the sun, length of the day, seasons and moon phases. 4…Read more…
Moon phases revealed a different kind of confusion
The Moon-phase misconception exposes a different problem: learners often blend together several related astronomical ideas.
Because eclipses involve Earth’s shadow and are visually dramatic, many people use that explanation to account for all lunar phases. The resulting model partially resembles real astronomy, making it difficult to abandon. Learners know shadows are involved somewhere in the Earth–Moon–Sun system, but they apply the idea in the wrong context. LPI [2SMC España]sciencemediacentre.esWhy aren't there eclipses every month?12 May 2026 — The most widespread and persistent misconception about the Sun-Earth-Moon system is c…
Research reviews and educational resources have documented recurring beliefs that:
- Earth’s shadow causes the Moon’s phases.
- The Moon produces its own light.
- The Moon is visible only at night. [lpi.usra.edu]lpi.usra.eduLPIPhasesMisconceptionsMoon Phases: Misconceptions and Educational Research. Common misconceptions include: The Moon can only be seen at…
- Clouds or atmospheric effects create lunar phases.
- The Moon’s phases are caused by its rotation rather than changing viewing geometry. [LPI]lpi.usra.eduLPISeasonsMisconceptionsCommon misconceptions include: Seasons are caused by Earth's distance from the Sun; Seasons are caused by Earth's…
These misconceptions have been recorded across different age groups and educational levels, suggesting that ordinary instruction often fails to reorganise the underlying model. [indico.unina.it]indico.unina.it2007 Preservice Elementary Teachers Conceptions of Moon PhasesBeeth, 1998a, 1998b, 1998c; Driver & Oldham, 1986… [Taylor & Francis Online]tandfonline.comA longitudinal study of conceptual change: Preservice elementary teachers' conceptions of Moon phases.Read mo…
Why traditional instruction missed the problem
One of the documentary’s most important contributions was showing a mismatch between classroom success and conceptual understanding.
Many interviewees had earned strong grades and could recall scientific vocabulary. Yet when asked to explain a phenomenon in their own words, they reverted to their private models. This suggested that conventional instruction often rewarded memorisation without probing underlying reasoning. [Annenberg Learner]learner.orgAnnenberg LearnerA Private UniverseInterviews are held with high school students and Ivy League graduates asking them to explain what cau… [SIU School of Medicine]siumed.eduSIU School of MedicineA Private UniverseInterviews are held with high school students and Ivy League graduates asking them to explain wha…
The interviews highlighted several recurring instructional weaknesses.
Students were rarely asked to explain mechanisms.
A learner could remember that “Earth is tilted” without understanding how tilt affects sunlight angle, daylight duration and seasonal heating. The correct term became attached to an incorrect causal story. [Eurasia Journal]ejmste.comEurasia Journalalternative-conceptions-of-astronomy-how-irish-secondaryMarch 18, 2021 — by A Cardinot · 2021 · Cited by 20 — seasons as a results of the Earth's distance to the Sun, underestimation of spatio…
New information was absorbed into existing beliefs.
Some students knew that Earth’s tilt mattered but interpreted tilt as making Earth physically closer to the Sun. Rather than replacing the distance model, they modified it. Researchers sometimes describe these as fragmented or hybrid conceptions. [Eurasia Journal]ejmste.comEurasia Journalalternative-conceptions-of-astronomy-how-irish-secondaryMarch 18, 2021 — by A Cardinot · 2021 · Cited by 20 — seasons as a results of the Earth's distance to the Sun, underestimation of spatio…
Astronomy requires difficult spatial reasoning.
Understanding seasons and Moon phases involves imagining three-dimensional relationships, motion over time and multiple frames of reference. Research consistently identifies spatial reasoning as a major challenge in astronomy learning. [OAPub]oapub.orgThe sample…Read more…
Everyday experience seems to support the wrong explanation.
People directly experience that closer objects feel warmer and that shadows change appearances. These observations provide intuitive support for misconceptions, making them more resilient than simple factual mistakes. The Christian Science Monitor [Beyond Penguins and Polar Bears]beyondpenguins.ehe.osu.eduMisconceptions about Day and Night, SeasonsThis article describes common misconceptions held by elementary students about the cause of da…
Why the documentary mattered to conceptual change research
A Private Universe became influential because it provided a vivid public demonstration of a conclusion already emerging from educational research: misconceptions are often stable conceptual systems rather than gaps in knowledge. [ADS Abstracts]adsabs.harvard.eduLater interviews were… [ScienceDirect]sciencedirect.comScienceDirectTeaching astronomy for pre-service elementary teachersby V Frède · 2008 · Cited by 33 — Refutation activities were found to…
The documentary also changed how many educators viewed incorrect answers. Instead of treating them as failures to memorise, researchers increasingly examined them as evidence of underlying reasoning. Interview techniques, concept inventories and diagnostic questioning gained importance because they could reveal the learner’s actual explanatory model. [PMC]pmc.ncbi.nlm.nih.govPMCWhen Is an Interview an Inter View?The Historical and Recent…by EJ Blown · 2022 · Cited by 9 — This paper provides a historical review of the interview research that has…
Its impact extended beyond astronomy. The film became a widely used illustration in teacher education programmes because it showed how even highly capable learners can preserve scientifically inaccurate explanations beneath a layer of correct terminology. [Center for Astrophysics]lweb.cfa.harvard.eduCenter for AstrophysicsCfA Education and Outreach — K-12 Professional DevelopmentA Private Universe (1987) is an award-winning short docu… [2iSTAR DB]istardb.orgAgan 2004 Stellar IdeasA Private Universe (Schneps 1989) documents the responses of Harvard graduates and faculty members who were asked about the cause of seas…
Lessons for teaching seasons and moon phases
Research that followed the documentary generally points in the same direction: conceptual change requires more than presenting the correct answer. Learners must actively confront the limits of their existing model and build a replacement explanation. [ScienceDirect]sciencedirect.comScienceDirectThe impact of teaching on students' definitions and…by E Kikas · 1998 · Cited by 188 — This longitudinal investigation wa… [Taylor & Francis Online]tandfonline.comA longitudinal study of conceptual change: Preservice elementary teachers' conceptions of Moon phases.Read mo…
Several teaching approaches have shown promise.
Start by uncovering the learner’s model
The interviews in A Private Universe worked because they asked students to explain and draw their ideas.
Questions such as “Why is it summer?” or “What causes a crescent Moon?” reveal much more than multiple-choice tests. Once misconceptions become visible, instruction can address them directly rather than assuming students already understand the underlying mechanism. [Annenberg Learner]learner.orgAnnenberg LearnerA Private UniverseInterviews are held with high school students and Ivy League graduates asking them to explain what cau…
Use models that make geometry visible
Physical models, observation programmes and carefully designed visualisations help students connect Earth, Moon and Sun positions with what they observe in the sky. Studies of astronomy instruction have repeatedly found that learners improve when they can relate multiple viewpoints and track motions over time. [Taylor & Francis Online]tandfonline.comA longitudinal study of conceptual change: Preservice elementary teachers' conceptions of Moon phases.Read mo… [Taylor & Francis Online]tandfonline.comA longitudinal study of conceptual change: Preservice elementary teachers' conceptions of Moon phases.Read mo…
Directly challenge common misconceptions
Research on conceptual change in astronomy has found benefits from “refutation” approaches that explicitly state a common misconception and then explain why it fails. Rather than ignoring incorrect ideas, these methods make them part of instruction. [ScienceDirect]sciencedirect.comScienceDirectThe impact of teaching on students' definitions and…by E Kikas · 1998 · Cited by 188 — This longitudinal investigation wa…
For example:
- If students think seasons are caused by distance from the Sun, compare Northern and Southern Hemisphere seasons.
- If students think Moon phases come from Earth’s shadow, compare ordinary lunar phases with the much rarer geometry of eclipses.
- If students think the Moon is visible only at night, have them observe daytime appearances. [LPI]lpi.usra.eduLPIPhasesMisconceptionsMoon Phases: Misconceptions and Educational Research. Common misconceptions include: The Moon can only be seen at… [LPI]lpi.usra.eduLPISeasonsMisconceptionsCommon misconceptions include: Seasons are caused by Earth's distance from the Sun; Seasons are caused by Earth's…
The lasting significance of A Private Universe
Decades after its release, A Private Universe remains memorable because it captured a central problem in science learning with unusual clarity. The striking part was never that some students answered incorrectly. The striking part was how confidently and systematically they explained their answers. Their reasoning revealed that instruction had often added scientific vocabulary without replacing older explanatory frameworks. [Annenberg Learner]learner.orgAnnenberg LearnerA Private UniverseInterviews are held with high school students and Ivy League graduates asking them to explain what cau… [Center for Astrophysics]lweb.cfa.harvard.eduCenter for AstrophysicsCfA Education and Outreach — K-12 Professional DevelopmentA Private Universe (1987) is an award-winning short docu…
The documentary’s enduring lesson is that misconceptions about seasons and Moon phases are not merely wrong facts waiting to be corrected. They are attempts to make sense of the world. Effective science teaching succeeds when it discovers those private explanations, exposes their limits and helps learners construct models that explain more than the misconceptions they replace. [Annenberg Learner]learner.orgAnnenberg LearnerA Private UniverseInterviews are held with high school students and Ivy League graduates asking them to explain what cau… [ScienceDirect]sciencedirect.comDesigning a powerful learning environment to promote…by H Küçüközer · 2013 · Cited by 26 — Common misconceptions regarding the eclipse…
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Further Reading
Books and field guides related to What A Private Universe Revealed. Use these as the next step if you want deeper reading beyond the article.
Welcome to the Universe
First published 2016. Subjects: Popular works, Relativity (Physics), Stars, Cosmology, nyt:science=2016-12-11.
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Endnotes
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Source: learner.org
Link: https://www.learner.org/series/a-private-universe/1-a-private-universe/Source snippet
Annenberg LearnerA Private UniverseInterviews are held with high school students and Ivy League graduates asking them to explain what cau...
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Source: lweb.cfa.harvard.edu
Link: https://lweb.cfa.harvard.edu/education/k12.htmlSource snippet
Center for AstrophysicsCfA Education and Outreach — K-12 Professional DevelopmentA Private Universe (1987) is an award-winning short docu...
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Source: sciencedirect.com
Link: https://www.sciencedirect.com/science/article/abs/pii/S0959475298000048Source snippet
ScienceDirectThe impact of teaching on students' definitions and...by E Kikas · 1998 · Cited by 188 — This longitudinal investigation wa...
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Source: blogs.ubc.ca
Title: conceptualizing misconceptions
Link: https://blogs.ubc.ca/stem2017/2017/01/12/conceptualizing-misconceptions/Source snippet
UBC BlogsConceptualizing Misconceptions – STEM12 Jan 2017 — “Relating back to Heather, one of her large misconceptions was her figure eig...
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Source: scienceinschool.org
Link: https://scienceinschool.org/article/2010/privateuniverse/Source snippet
A Private Universe online resources, By Matthew H...7 Dec 2010 — The film also mentions another aspect in which misconceptions prevail o...
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Source: lpi.usra.edu
Link: https://www.lpi.usra.edu/education/pre_service_edu/PhasesMisconceptions.shtmlSource snippet
LPIPhasesMisconceptionsMoon Phases: Misconceptions and Educational Research. Common misconceptions include: The Moon can only be seen at...
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Source: lpi.usra.edu
Link: https://www.lpi.usra.edu/education/pre_service_edu/SeasonsMisconceptions.shtmlSource snippet
LPISeasonsMisconceptionsCommon misconceptions include: Seasons are caused by Earth's distance from the Sun; Seasons are caused by Earth's...
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Source: sciencedirect.com
Link: https://www.sciencedirect.com/science/article/abs/pii/S0273117706000512Source snippet
Apparent movement of the sun, length of the day, seasons and moon phases. 4...Read more...
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Source: indico.unina.it
Title: 2007 Preservice Elementary Teachers Conceptions of Moon Phases
Link: [https://indico.unina.it/event/73/contributions/1042/attachments/359/634/2007-_Preservice_Elementary_Teachers_Conceptions_of_Moon_Phases.pdf](https://indico.unina.it/event/73/contributions/1042/attachments/359/634/2007-_Preservice_Elementary_Teachers_Conceptions_of_Moon_Phases.pdf)Source snippet
(Beeth, 1998a, 1998b, 1998c; Driver & Oldham, 1986...
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Source: oapub.org
Link: https://oapub.org/edu/index.php/ejes/article/view/3522Source snippet
The sample...Read more...
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Source: adsabs.harvard.edu
Link: https://adsabs.harvard.edu/full/1996ASPC…89…46SSource snippet
Later interviews were...
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Source: pmc.ncbi.nlm.nih.gov
Title: PMCWhen Is an Interview an Inter View?
Link: https://pmc.ncbi.nlm.nih.gov/articles/PMC8720161/Source snippet
The Historical and Recent...by EJ Blown · 2022 · Cited by 9 — This paper provides a historical review of the interview research that has...
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Source: sciencedirect.com
Link: https://www.sciencedirect.com/science/article/abs/pii/S0273117707011489Source snippet
ScienceDirectTeaching astronomy for pre-service elementary teachersby V Frède · 2008 · Cited by 33 — Refutation activities were found to...
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Source: sciencedirect.com
Link: https://www.sciencedirect.com/science/article/abs/pii/S0360131513001632Source snippet
Designing a powerful learning environment to promote...by H Küçüközer · 2013 · Cited by 26 — Common misconceptions regarding the eclipse...
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Source: learner.org
Link: https://www.learner.org/series/a-private-universe/Source snippet
A Private UniverseA Private Universe. Discover why even Ivy League graduates don't really grasp basic science concepts in this video docu...
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Source: youtube.com
Title: A Private Universe
Link: https://www.youtube.com/watch?v=p0wk4qG2kIgSource snippet
Why Are There Seasons?...
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Source: nsdl.library.cornell.edu
Link: https://nsdl.library.cornell.edu/websites/wiki/index.php/MSP_MiddleSchoolPortal/The_Reasons_for_the_Seasons.htmlSource snippet
The video documentary A Private Universe, produced by the Harvard-Smithsonian Center for Astrophysics, explores why so few...
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Source: sciencemediacentre.es
Link: https://sciencemediacentre.es/en/why-arent-there-eclipses-every-month-most-common-misconceptions-and-how-debunk-them-inside-andSource snippet
Why aren't there eclipses every month?12 May 2026 — The most widespread and persistent misconception about the Sun-Earth-Moon system is c...
Published: May 2026
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Source: siumed.edu
Link: https://www.siumed.edu/academy/private-universe.htmlSource snippet
SIU School of MedicineA Private UniverseInterviews are held with high school students and Ivy League graduates asking them to explain wha...
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Source: csmonitor.com
Title: Seasons are caused by Earth s distance from the sun
Link: https://www.csmonitor.com/Science/2013/1031/10-common-scientific-misconceptions/Seasons-are-caused-by-Earth-s-distance-from-the-sunSource snippet
The Christian Science MonitorSeasons are caused by Earth's distance from the sun31 Oct 2013 — A sensible explanation for the seasons is t...
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Source: beyondpenguins.ehe.osu.edu
Link: https://beyondpenguins.ehe.osu.edu/issue/polar-patterns-day-night-and-seasons/common-misconceptions-about-day-and-night-seasonsSource snippet
Misconceptions about Day and Night, SeasonsThis article describes common misconceptions held by elementary students about the cause of da...
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Source: ejmste.com
Title: Eurasia Journalalternative-conceptions-of-astronomy-how-irish-secondary
Link: https://www.ejmste.com/download/alternative-conceptions-of-astronomy-how-irish-secondary-students-understand-gravity-seasons-and-the-10780.pdfSource snippet
March 18, 2021 — by A Cardinot · 2021 · Cited by 20 — seasons as a results of the Earth's distance to the Sun, underestimation of spatio...
Published: March 18, 2021
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Source: tandfonline.com
Link: https://www.tandfonline.com/doi/full/10.1080/09500693.2018.1522014Source snippet
A longitudinal study of conceptual change: Preservice elementary teachers' conceptions of Moon phases.Read mo...
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Source: istardb.org
Title: Agan 2004 Stellar Ideas
Link: https://istardb.org/wp-content/uploads/tainacan-items/1018/19915/Agan_2004_Stellar-Ideas.pdfSource snippet
A Private Universe (Schneps 1989) documents the responses of Harvard graduates and faculty members who were asked about the cause of seas...
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Source: tandfonline.com
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Taylor & Francis OnlineAddressing children's alternative frameworks of the Moon's...by M Barnett · 2002 · Cited by 262 — To assess stude...
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Title: a private universe
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Private Universe - Alexander Street, a ProQuest CompanyThis award-winning program traces the problem through interviews with Harvard grad...
Additional References
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Link: https://www.scribd.com/document/269350/A-Private-UniverseSource snippet
Misconceptions in Astronomy Education | PDF | MoonA Private Universe. Cambridge, MA: Harvard University, Smithsonian Institution. Transcr...
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Smithsonian InstitutionA private universe [videorecording]: minds of our own /..."How can students graduate from prestigious schools li...
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Source: researchgate.net
Link: https://www.researchgate.net/publication/343367234_Diagnosing_Students%27_Misconceptions_of_Astronomy_Through_Concept_CartoonsSource snippet
concepts of moon phases, seasonal changes, the position of the sun in the sky...
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Source: researchonline.jcu.edu.au
Title: Other astronomical phenomena
Link: https://researchonline.jcu.edu.au/42908/1/42908_Mills_etal_2016_accepted%20version.pdfSource snippet
James Cook University Research OnlineLearning in Earth and space science: a review of conceptual...by R Mills · 2016 · Cited by 59 — The...
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Source: wyoscholar.uwyo.edu
Link: https://wyoscholar.uwyo.edu/items/ac69960b-d1fb-49d6-8b53-e6d2bad10d45Source snippet
Wyoming ScholarsLunar Phases: Uncovering Misconceptions through...by SJ Hackworth · 2015 — The purpose of this project is to research an...
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Source: youtube.com
Link: https://www.youtube.com/watch?v=1iFMp2NUJVsSource snippet
A), the film reveals the private theories about astronomy...
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Source: youtube.com
Title: Misconceptions in Astronomy
Link: https://www.youtube.com/watch?v=0vfikrdozj4Source snippet
The Cause of the SeasonsSeasons are not caused by the changing distance between Earth and Sun they are caused by the tilt of the Earth's...
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Source: files.eric.ed.gov
Link: https://files.eric.ed.gov/fulltext/EJ1113875.pdfSource snippet
Science Teachers' Beliefs about Astronomy...by G Ozkan · 2016 · Cited by 13 — Abstract The purpose of this study was to investigate pres...
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Link: https://www.atlantis-press.com/article/125989949.pdfSource snippet
Preliminary Development of [Refutation Texts]({{ 'refutation-texts/' | relative_url }}) for...by D Devianty · 2023 · Cited by 2 — A common misconception among children and adults i...
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Source: youtube.com
Title: Common Misconceptions About the Moon Phases
Link: https://www.youtube.com/watch?v=wR1ZzN1D5P0Source snippet
Teaching Astronomy: From Intuition to Science...
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