“Stars Falling to Earth”—Mental Models of Comets and Meteors

Abstract

The present study examines students’ conceptions of comets and meteors using qualitative research methods. A total of 35 semi-structured interviews were conducted with students in grades 7 and 9 in Germany, aiming to gain a richer understanding of how learners conceptualize these phenomena. We identified and categorized distinct mental models related to both the appearance (gestalt) and function of comets and meteors, which are reported in detail in this article. Ideas about meteors tend to align with scientific explanations, whereas answers about comets vary widely and often lack a basic understanding. Based on our data, we recommend that educational approaches begin with a clear introduction to physical properties to establish a solid foundation of knowledge. Both aspects of the gestalt and functionality of comets and meteors should be considered and emphasized in the teaching and learning process.

1. Introduction

Astronomy is a key component of many international science curricula (Salimpour et al., 2021). It has consistently shown a high potential to capture and sustain student interest, often more so than other areas of science education. This increased engagement makes astronomy an ideal context for exploring how students construct scientific understanding. To support meaningful learning in this domain, it is essential to investigate how students form mental models of astronomical phenomena, especially since such models often reveal persistent misconceptions or incomplete understandings.

Previous research has demonstrated the value of probing students’ ideas about fundamental celestial objects. Studies have explored the conceptions of students of the Earth (Nussbaum & Novak, 1976), the Sun (Bryce & Blown, 2013), stars (Bitzenbauer et al., 2023), the Galaxy (Korur, 2015), and even more complex entities such as black holes (Ubben et al., 2022). These investigations have provided insight into both the cognitive challenges students face and the conceptual pathways they follow as their understanding develops. However, despite their visibility and significance in both scientific and popular discourse, other solar system objects—such as comets and meteors (often referred to as “shooting stars”)—have received comparatively little attention in educational research. Some examples of studies exploring these were conducted by Serttaş and Yenilmez Türkoğlu (2020) and Çevik and Kurnaz (2017), though the main focus in these studies was not on gaining an in-depth understanding of their conceptions in detail but a broader understanding of them in conjuncture with, e.g., those of the Sun or other phenomena.

To address this gap, the present study examines students’ conceptions of comets and meteors using qualitative research methods. We conducted 35 semi-structured interviews with students in grades 7 and 9 in Germany, with the aim of gaining a richer understanding of how learners conceptualize these phenomena. By analyzing their explanations, visualizations, and reasoning patterns, we were able to identify and categorize distinct mental models related to both the appearance and function of comets and meteors. These initial findings contribute to the larger effort to map the astronomical thinking of students and may inform the development of targeted instructional strategies in the future.

2. Theoretical Background of Mental Models

In this study, the term mental model is used to describe the complex network of ideas, perceptions, and conceptual structures that students use to make sense of astronomical phenomena. This rationale for using this terminology was grounded in its established relevance within the educational and cognitive science literature, as demonstrated by recent studies (Bitzenbauer & Ubben, 2025; Harrison & Treagust, 1996; Horst, 2016; Ke et al., 2005). The term has previously been used to describe the cognitive representations that learners construct when grappling with phenomena, scientific laws, and theoretical frameworks (Horst, 2016).

Building on this conceptual foundation, recent research has introduced a more differentiated view of mental models by distinguishing between two fundamental dimensions: appearance (or “gestalt”, which we will use in the following article) and functionality. This nuanced approach acknowledges the inherent complexity of mental models and allows for a more targeted analysis of student thinking. The dimension of gestalt refers to the surface-level features, including visual, sensory, or descriptive characteristics, that form the outward appearance of a mental model. In contrast, functionality refers to the deeper, often more abstract features that define how a phenomenon is understood to behave or operate within a conceptual system (Piaget, 2013). These two aspects, gestalt and functionality, have been shown to exhibit a degree of independence in learners’ mental constructions (Bitzenbauer & Ubben, 2025), which is why the present study addressed them as separate analytical categories during data collection and interpretation.

Within the domain of astronomy education, mental models often adopt a visual representational form. This is not surprising because the discipline is highly reliant on images, diagrams, and other visualizations to communicate measurements and observations. Consequently, in this context, the term gestalt takes on an especially visual connotation, referring not just to the structural qualities of a concept but to its imagined or perceived appearance. It is important to note that mental models are inherently internal and cannot be directly observed. Instead, they are inferred from verbal explanations, illustrative drawings, and task-related actions (Ubben et al., 2022). Investigating both the gestalt and functionality of students’ mental models therefore offers a more comprehensive perspective on their conceptualizations of astronomical phenomena.

The importance of studying mental models in educational settings cannot be overstated. A clear understanding of common mental models, including the misconceptions or partial understandings they may contain, equips educators to better scaffold students’ learning. With this insight, teachers can tailor instructional strategies to address specific gaps or reinforce productive ideas. This process supports more robust conceptual development. Drawing on findings from other subject areas where mental models have been analyzed in a similar way, this study seeks to offer specific foundational insights into students’ ideas about comets and meteors. Through this focused investigation, the study aims to expand our understanding of how learners conceptualize lesser-studied celestial objects and contribute to a more complete picture of astronomical cognition in school settings.

3. Research Question

Mental models have been thoroughly examined in many domains of physics education, as evidenced by comprehensive collections such as that of Schecker et al. (2018). In contrast, the body of research focused specifically on astrophysics remains comparatively underdeveloped. Within this field, only limited attention has been devoted to certain phenomena, particularly comets and meteors. The existing studies have largely focused on more fundamental topics, such as students’ conceptions of the Earth (Nussbaum & Novak, 1976) or their understanding of the spatial relationships between the Earth, the Sun, and the Moon (Bryce & Blown, 2013). However, in-depth qualitative investigations into learners’ ideas about comets and meteors regarding their gestalts and functionality are noticeably scarce.

In the case of meteors, it is plausible that students have observed such events first-hand. These experiences may lead them to form intuitive, pre-instructional mental models based on personal perception. In contrast, conceptions of comets are more likely shaped by indirect sources, such as media portrayals or cultural imagery. An example is the depiction of the biblical star of Bethlehem, often illustrated with a prominent glowing tail.

Given the significance of comets and meteor showers within the broader context of astronomy education and the limited research on how students conceptualize these phenomena, there is a clear need for further exploration. Understanding students’ mental models is essential for designing effective instructional approaches and addressing potential misconceptions in this area.

Consequently, this study was guided by the following central research questions:

• RQ1: How do students imagine comets and meteors?
• RQ2: What statements about the properties of comets and meteors do students make?

4. Methods

Mental models are internal cognitive constructs and, as such, cannot be directly observed. They exist as part of students’ thought processes and therefore must be inferred through external expressions. Typically, students do not articulate formal or didactically developed models when asked; instead, they behave and respond as if their internal representations accurately reflect reality (Schecker et al., 2018, p. 9). To uncover such implicit ideas, interviews have proven to be a particularly effective and well-established method. Especially when investigating previously undocumented or unfamiliar mental models, interviews serve as a valuable exploratory tool. The literature consistently identifies interviews as a suitable and widely accepted method to gain insight into mental models, particularly in under-researched subject areas (Schecker et al., 2018, p. 17).

Interviews offer the distinct advantage of allowing participants to verbalize their thoughts in real time. In contrast to open-ended questionnaires, interviews allow the researcher to guide the conversation, clarify responses, and ask follow-up questions as needed. This is especially beneficial given the current state of research and the nature of the research question. Furthermore, it is well documented that oral interviews tend to produce more detailed and elaborated responses compared to written formats (Schecker et al., 2018, p. 17), thereby enhancing the richness and depth of the collected data.

A similar qualitative interview methodology has been effectively applied by Ubben et al. (2022), who used it to collect extensive data on the mental models of students in a related area. For further methodological background and justification, see also Forman and Damschroder (2007) and Kuckartz (2012).

4.1. Design of the Interviews

In alignment with the research questions, a semi-structured interview format was selected. To support this approach, an interview guide was developed in the form of a list of open questions, which strengthened reliability, as it enabled the provision of identical guidance through the interview. This format struck a balance between structure and flexibility: it ensured that the core objectives and thematic areas of the interview were clearly defined, while still providing students with ample opportunities to express their thoughts in their own words (Döring & Bortz, 2016, p. 358).

Test interviews were conducted to increase the validity of the interview guide. For this purpose, two test subjects from the ninth grade were available. Both were interviewed about meteors and comets. The interviews were recorded, transcribed, and reflected upon with two experts in physics education. It became clear that for some questions (e.g., “where are shooting stars” or “where are comets?”), additional information was needed to provide assistance in building a proper answer. The interview guidelines were adapted accordingly in order to allow open questions to be asked on the one hand, but to support the interviewees in developing their answers with optional additions if necessary (e.g., “as high as the stars, like the moon or like an airplane?”). It should be noted that these aids could have steered the answers in certain directions. However, this was countered by the problem that some of the interviewees may have been unable to make their ideas explicit without a comparative example. It also became apparent that the transcription could focus primarily on the content and that gestures, body language, and intonation did not need to be transcribed in this context.

4.2. The Discussion Guide for the Interview About Comets

The key points in the discussion guide for the interview about comets were as follows. In the brackets are additions to help the respondent form their answers if necessary.

• Have you ever heard of a comet? (Television, or have you ever seen one yourself?)
• What does a comet look like? (A reference to observation in the night sky can be made here if the test person is already concentrating on the shape (lump of stone, lump of ice, etc.).)
• How far away is a comet from us?
• How does a comet move in space? (trajectory, direction, speed)
• Where is the comet when we can no longer see it?
• What is a comet made of, what kind of material is it?
• When I fly past a comet on a rocket, what do I see?
• How big do you imagine a comet to be? Can you find a comparison? (As big as the Earth, as big as the moon, as big as a soccer ball, as big as a golf ball)
• How is it that a comet has a tail?
• What is the tail made of, what kind of material is it?

4.3. The Discussion Guide for the Interview About Meteors

The corresponding key points for the interviews about meteors that were used to guide the interactions with the students were as follows:

• Have you ever seen a shooting star? What did you see?
• Describe your observation:

  -

  How fast is the shooting star moving?

  -

  What color is the shooting star?

  -

  How high above the Earth’s surface do shooting stars fly? (e.g., As high as the stars, like the moon, like an airplane?)

  -

  How does a shooting star move in space? (trajectory, direction, speed)

  -

  Where are the shooting stars when we can no longer see them?

• Why do shooting stars shine? (e.g., the moon does not shine by itself, but the sun and the stars do.)
• How big is a shooting star? Can you find a comparison? (e.g., as big as the moon, as big as a soccer, as big as a golf ball, as big as a grain of sand?
• If I fly past a shooting star in a rocket, what do I see? (it can be useful to differentiate this from the night sky to clarify the perspective)
• What is a shooting star made of, what kind of material is it?

Based on an initial technical and curricular clarification of the topics regarding comets and meteors, the following categories were formed to be scientifically accurate and aligned with current experts’ understanding. Different terms are used depending on where the meteors are located: If one is in space, it is called a meteoroid. When it enters the Earth’s atmosphere and burns up, it is called a meteor. If a piece of meteor remains intact and lands on the surface of the Earth, it is called a meteorite. For simplicity and since it refers to the observable phenomenon, we will mainly use the term meteor without differentiating between the others.

• Material: Meteors usually consist of rock or metal. Comets, in contrast, are composed primarily of ice, dust, and organic material, often described as a mixture of “ice, dust, and dirt.”
• Shape: This category refers to the size, appearance, and structural components of the objects. A comet is composed of a nucleus, a surrounding coma, and one or more tails. Although the nucleus typically measures between 1 and 50 km in diameter, the coma can extend up to ${10}^5$ km, and the tail can reach lengths of several million kilometers. Meteors, by comparison, are much smaller, ranging from millimeters to meters in size, and appear as solid fragments without a visible atmosphere.
• Behavior: The term “behavior” (see Section 2) encompasses the dynamic processes and physical interactions of celestial bodies, including how they emit light and how they evolve over time. For instance, as a comet approaches the Sun, solar radiation causes its icy components to sublimate, forming a coma and a tail. Meteoroids, on the other hand, become visible as meteors when they enter the Earth’s atmosphere and heat up due to friction, causing them to glow.
• Orbit: Comets and meteoroids follow distinct orbital paths. Meteoroids generally travel in relatively circular orbits and only become visible as meteors when they intersect with the Earth’s atmosphere. Comets, in contrast, typically follow highly elliptical orbits, allowing them to be observed even when they are far from the Earth and the Sun.
• Origin: Comets originate from distant regions of the solar system, such as the Oort Cloud or the Kuiper Belt. Meteoroids are smaller fragments that break off from asteroids or comets, often as a result of collisions.
• Observation: Comets are slow-moving objects that can often be observed over several days or weeks, either with the naked eye (especially when near the Earth) or via telescopic time-lapse recordings. They are frequently identified by their prominent tails. Meteors, in contrast, appear as brief flashes of light—therefore they are often referred to as “shooting stars”—that streak rapidly across the sky, sometimes resembling fireballs.

A total of 35 semi-structured interviews were conducted and subsequently analyzed for this study. Among these, 18 interviews specifically addressed the ideas of students about comets, while 17 focused on their conceptions of meteors. The participants were students drawn from grades 7 through 9, representing early to mid-adolescence, and were recruited from two secondary schools in Germany. This age range was deliberately chosen to capture the developmental stage during which many students first encounter formal instruction in astronomy. Their participation was voluntary and completely anonymous. The results were evaluated solely on the basis of anonymized transcripts. The interviews aimed to obtain rich qualitative data regarding mental models, allowing for an in-depth exploration of conceptual understandings and misconceptions in these relatively underrepresented areas of astrophysics education.

At the end of an interview, the interviewees were faced with a visual stimulus and asked to comment on it. The sketches were deliberately kept vague, but nevertheless addressed essential elements of comets and meteors. The image stimuli can be seen in Figure 1 and Figure 2. They could, for example, provide a potential opportunity to articulate existing ideas that were not previously addressed by the interview questions. At the same time, surprised or astonished statements were a clear sign that the concepts were not understood.

4.4. Qualitative Content Analysis

For the analysis of the interview data, a method of qualitative content analysis was applied, as described by Kuckartz and Rädiker (2023). This method was chosen because it is open and unbiased towards the data, allowing for an exploratory approach without requiring predefined theoretical assumptions, while still offering a methodologically rigorous and systematic framework for analysis. At its core, the method involves examining textual material by developing and applying a structured system of categories that support the interpretation of the data through clear organization and thematic segmentation. The methodological quality of this approach is strongly influenced by how well the category system reflects both the research question and the actual data gathered.

In this study, the construction of the category system followed the principles of qualitative content analysis through content restructuring. The process began deductively, with six overarching categories derived from the technical differentiation between comets and meteors: Material, Form, Behavior, Orbit, Origin, and Observation. These main categories served as the basis for the coding process. Within each category, subcategories were developed inductively, emerging directly from the students’ responses during the interviews. This combination of deductive and inductive coding ensured that the analysis remained grounded in scientific accuracy and sensitive to the authentic perspectives expressed by the participants.

To enhance transparency and reproducibility, the presentation of the results includes a selection of tables that presents some of the codes along with the following: (a) the number of individual students who mentioned them, (b) a brief definition used for coding, and (c) an illustrative example from the interviews. When quoting participants, a coding system is used to clearly and anonymously attribute the responses. Each interviewee was labeled with a composite code consisting of their school, grade level, and interview number in the format <school>-<grade>-<person> (e.g., school1-7-1). This allowed for intersubjective traceability while preserving participants’ anonymity.

Quantitative distributions are given in the code tables and in the text. However, these should not be interpreted as quantitative results without further ado, as the total number of interviews was very small (see also the chapter on limitations). Furthermore, in the case of open questions, it cannot necessarily be concluded from the absence of a statement that a certain idea does not exist simply because it has not been made explicit. The frequently observed ideas mentioned at the end of the evaluation should therefore be regarded as a take-home message regarding probable thought patterns.

5. Results

5.1. Results for Comets

The results regarding the aspects of the mental models identified from the 18 interviews on comets are presented below. These aspects are grouped into the dimensions of gestalt and Function (see Section 2). In

Table 1. Codes relating to the shape of comets. # means the number of interviewees for whom this code was used.

Code	#	Definition	Example
Rocky chunk	13	The shape of the comet is compared to a stone, chunk, or rocky mass.	I guess like a stone. Kind of with small holes. It’s not exactly round but uneven, I’d say. And, yeah, it’s definitely a bit larger. (school1-9-3)
Size scale (m)	13	The comet’s size is given in meters, or a comparison matches that scale.	Pretty big. Maybe like ten cars or something. (school1-7-6)
Irregular surface	8	The comet’s surface is described as irregular, e.g., hilly, jagged, or angular.	Oh right. I think the small stone is the comet. And that’s about how I’d imagine it—with a rough surface. (school1-9-13)
Rounded shape	6	The shape of the comet is described as round or ball-like.	No idea. So first of all, like a giant sphere. Probably with lots of holes, like I said. And, yeah, a very rough surface. (school1-7-4)
Gray color	3	The color of the comet or its surface is described as gray.	Most people say it’s grey or has an earthy tone. (school1-9-11)
Tail	3	A tail is described as being part of the comet.	I think what you see is depending on how close you are. But if you fly relatively close by, I think you’d see a huge chunk flying past, and behind it there’s a kind of tail, yeah. (school1-9-6)
Size scale (km)	3	The comet’s size is given in kilometers, or a comparison matches that scale.	Yeah, definitely not as big as a planet. I guess (…) about the size of Rheine, if you take that city—about that big. (school1-9-3)

and

Table 2. Codes relating to the function of comets. # means the number of interviewees for whom this code was used.

Code	#	Definition	Example
High speed	8	The comet’s high speed is mentioned as the cause of a process.	[Asked why a comet has a tail] I think somehow when it burns up. I mean, it flies down at high speed. And then maybe the fire trails behind it, and that looks like a tail. (school2-7-2)
Air	8	Interaction of the comet with the Earth’s atmosphere or with air in general.	And maybe it’s like, when it flies through space, it’s very fast. And then there’s airflow when it enters the Earth’s atmosphere. (school1-9-17)
Fire	8	The comet is burning or exhibits flames or fire.	It’s big, I think black, darker. And when it comes down, I think it burns or something. (school1-7-6)
Heat	6	Heat generation on the comet.	It gets warm from the high speed and then somehow a comet forms due to the heat. (school1-9-6)
Tail	3	Coded when the dynamics leading to the formation of a tail are described.	[Asked why a comet has a tail] Maybe because when it moves, that somehow causes it. (school1-7-2)
Movement	2	Coded when the movement of the comet is given as the cause of a process.	Same example as above.

, some of the codes, the frequency with which they were mentioned, their definitions, and examples are provided.

5.1.1. General Appearance (gestalt)

In almost all cases, the gestalt of a comet was described as that of a rock. It was typically characterized as having a round shape with an irregular surface, often described as “jagged” or “hilly,” and colored in shades of gray, brown, or black. When a tail was mentioned, it was directly connected to the core of the comet, which was described as a rock. The students were also asked to estimate the size of a comet. Their responses were given as comparisons, which ranged widely. The most common were comparisons in the meter range, such as to a car, a person, or a football field. Significantly larger or smaller sizes were also infrequently mentioned.

5.1.2. Material (gestalt)

The majority of the interviewed students described a comet as being composed of rock. One student compared the material of a comet to Moon rock. Statements that did not assume rock was the primary material were rare.

5.1.3. Observation (gestalt)

When asked about observing a comet from the night sky, some students responded by describing its form, imagining what the comet might look like from a close-up perspective.

In the most frequently coded subcategory of Observation, the students described a relatively small point glowing in the sky. One student referred to it as a “bright point” (e.g., school2-7-10). Comparisons were also made to other celestial phenomena, such as descriptions of a comet resembling a “shooting star” (meteor) or a regular star. The presence of a tail did not necessarily imply that it was visible from the Earth. However, some students reported that a tail trailing behind the comet could be seen.

A few students claimed that comets could not be observed with the naked eye. One student explained this by saying that they had never seen a comet in the night sky and therefore assumed that comets must not be visible without a telescope.

5.1.4. Tail (Function)

Most of the coded interview excerpts that addressed the comet’s tail related to the comet’s movement and speed. The students either explicitly mentioned a high speed or generally referred to motion as being the cause of the tail, without quantifying the velocity. A typical pattern involved associating a high speed with heat generation, sometimes invoking fire as a result. Interestingly, air or the Earth’s atmosphere was often cited in these cause-and-effect explanations. Many students maintained that the speed was the cause of the tail’s appearance.

5.2. Orbit (Function)

Most students attributed a high speed to comets (“I think that it moves relatively quickly.” (school1-9-1)). Few assumed slow movement or gave ambiguous statements. When estimating the distance of a comet from the Earth, the students commonly used analogies, for example, by comparing it to the distance between the Earth and the Moon, the Earth and the Sun, or the Earth and the International Space Station (ISS). Statements that placed the comet very close to the Earth (such as within the atmosphere or at the same distance away as the ISS) were coded as “close to Earth”. Both near-Earth positions and distances relative to that from the Moon were frequently mentioned, while comparisons to the Sun were less common.

When asked about a comet’s trajectory, many students described a circular path or orbit. Some identified the Earth as the center of this orbit, while others described a general circular trajectory without specifying a center. Several students imagined the comet moving through space in a straight line, categorized as “flight through space”. Others assumed a “flyby of Earth”, i.e., that a comet becomes invisible after passing the Earth. Another explanation for a comet’s disappearance from view was that it remains in the same position but cannot be seen anymore. This was suggested to perhaps be due to being outshone by the Sun. Comparisons were made to stars, which are not visible during the day due to the brightness of the Sun.

5.3. Results for Meteors

The results regarding the aspects of the mental models identified from the 17 interviews on meteors are presented below. These aspects are also divided into the gestalt and Function. In

Table 3. Codes related to observation of meteors. # means the number of interviewees for whom this code was used.

Code	#	Definition	Example
Seconds	15	The shooting star is visible for a duration in the order of seconds.	And you don’t see them for long. Like, you just see them like when you’re standing and a car races past you. That’s how fast the shooting stars were. (school2-7-1)
Bright or white	11	The shooting star is described as white or bright in the night sky.	I can’t really describe the color. But it was really bright. Like a whitish yellow. (school2-7-1)
Yellow	9	The shooting star is described as yellow or golden in the night sky.	Well, if the film got it right, kind of yellow to gold. Maybe shimmering a little. (school2-7-7)
Streak	7	The shooting star is seen as an elongated, streak-like light phenomenon in the night sky.	A thin streak across the sky that just flew past. (school2-7-11)
Only in film/TV	5	Coded when the student reported having only seen a shooting star in media such as films or TV.	[Asked about a “shooting star” in a movie or book] I’ve seen one in a movie before. (school2-7-7)
Tail	4	A tail is observable on a shooting star.	A star, and it had a tail behind it, it was sparkling. (school1-9-12)
Star	4	The shooting star is compared to a regular star.	It basically looked about like a normal star. More or less. (school1-7-1)

and

Table 4. Codes related to the trajectory of meteors. # means the number of interviewees for whom this code was used.

Code	#	Definition	Example
Flyby	9	The object flies past the Earth.	Well, I guess it either flies past Earth or just barely, I’m not sure, into Earth’s orbit maybe. I think it flies past or into Earth, but I don’t think it’s heading straight for Earth, more likely on a curved path. (school1-9-5)
Within atmosphere	8	The object moves within the Earth’s atmosphere.	Well, I think a shooting star maybe even flies not as far away as the other stars, but I think a shooting star is just barely in the atmosphere or something. (school1-7-3)
Circular path	5	The object moves in a circular orbit.	Well, I don’t know, but probably it keeps flying around the Earth, and I just can’t see it because, well, the Earth is round and maybe it’s on the other side or something. (school1-7-3)
Collision course	4	The object moves directly toward the Earth (on a “collision course”).	Yeah, and then kind of like, I’m not sure, more like flying toward Earth. Or maybe not exactly toward, maybe past it. (school2-7-5)
Disappears after observation	3	The object disappears after being seen, but does not burn up.	[Asked where a shooting star goes when it is not seen anymore] I guess nobody knows. But you can guess it either went back behind the stars or just isn’t there anymore. (school2-7-9)
Position compared to that of Moon	3	The object is located using a comparison to the location of the Moon.	I don’t think it was as low as a plane, I think it was way higher. I think like—yeah, about like the moon, more than a plane for sure. Maybe a bit farther than the moon. (school1-9-16)
Position compared to that of stars	3	The object is located using a comparison to the location of the stars.	I guess it was as high as the stars. I mean, the name “shooting star” says that too. (school2-7-9)
Above the atmosphere	3	The object is located near the Earth but above the atmosphere.	Yeah, it did look like it was like not in the sky like a plane but a bit farther away. But I don’t think as far as the moon or sun. Maybe like the ISS or satellites or something like that. (school1-9-5)
Straight	3	The object moves in a straight line.	The shooting star moved across the sky in a straight line. (school1-9-5)
Curved or arched	3	The object’s trajectory is described as curved or arched.	I don’t imagine the star coming straight toward Earth. Not directly straight. More like it’s being pulled in, which makes it curved. (school1-7-5)

, some of the codes, the frequencies with which they were mentioned, their definitions, and examples are provided.

5.3.1. General Appearance (gestalt)

In the category of gestalt, students were asked how large they imagined a “shooting star” to be. The German term for “shooting star” (“Sternschnuppe”) was used in the interview questions, as it is much more common than the term “meteor” (also “Meteor” in German with respect to a “Meteoroid”). Due to the variety of size comparisons, these responses were assigned to the deductive categories Kilometer, Meter, and Centimeter. The idea that meteors are in the meter range dominated with ten coded cases. For example, one student compared their size to that of a ping-pong table (school1-7-1). In fewer cases, the Centimeter category and the Kilometer category were coded.

Furthermore, when asked about the shape of meteors, some students described a glowing or burning appearance, similar to the explanations in the Function category. For example, their appearance was compared to that of a fireball (school1-7-3). This category was coded for several times, approximately matching the frequency of codes in the corresponding function-related category for comets. Some students described an abstract glow when asked about the form of a meteor. One student used the term “light ball” (school1-9-2), mentioning it leaves a tail behind.

As with comets, the category Rock was formed inductively for meteors. In this category, meteors were described as a chunk, a stone, or a rock. In the category Compared to a Star, students described meteors using comparisons to stars. In some cases, the distinction between a meteor and a star appeared to dissolve. This is evident in the following response: “So you would definitely see several, for sure. And basically, you would just see a normal star, I think” (school2-7-9). The student did not merely draw a comparison, but equated a meteor with a star. A similar equivalence was also less frequently observed between comets and meteors. In response to a question about the form of a meteor, one student stated, “So you will see a comet. Basically like a big rock” (school2-7-1). Some students also described a tail, which from a scientific perspective, is more accurately attributed to a comet.

5.3.2. Material (gestalt)

Nearly all of the students in the study believed that meteors are composed of rock. Only a few students were unable to provide information about their material or made comparisons with the materials of comets or stars.

5.3.3. Observation (gestalt)

Most of the students reported having personally observed a meteor. Only five of the seventeen students interviewed on this topic stated that they had seen one only in movies or on the television. As a result, it was relatively easy to initiate discussions with students about their experiences, leading to rich descriptions of meteor observations.

Almost all the students agreed that a meteor is visible in the night sky for only a few seconds. An opposing view, that meteors remain visible for a longer duration in the order of minutes, was expressed by only a few students, all of whom had not personally witnessed one. The color of a meteor was described most frequently as bright, white, or yellow. So the categories “Bright/White” and “Yellow” were coded quite often. Other colors such as red, orange, and gold were also mentioned, although less frequently. The number of coded mentions exceed the number of cases, indicating that the students often listed multiple colors.

More detailed descriptions beyond that of meteors’ color and duration fell into the categories Streak, Tail, and Star. The Streak category was the most frequently coded. About every second person surveyed described an elongated, streak-like light phenomenon in the night sky. In fewer cases, students reported observing a tail or indicated that the appearance of a meteor resembled that of a star.

5.3.4. Orbit (Functionality)

The first aspect of the overarching category Orbit concerned the distance of the meteor from the Earth’s surface during observation (“flight altitude”). A large portion of the interviewed students assumed that a meteor is located within the Earth’s atmosphere while it is observed. This description of the flight altitude was the most common. Less frequently mentioned was a location in near-Earth space, just above the Earth’s atmosphere. To describe this positioning, comparisons were made to the locations of satellites or the International Space Station (ISS). In a few cases, students estimated the distance using the Earth–Moon distance as a reference. Another few students believed that the meteor was as far away as the stars.

Furthermore, students were asked in the interviews how a meteor moves, i.e., about its orbit or along its “flight path”. It also became apparent that questions about the orbit of a meteor could lead to the description of functional aspects, particularly when it was described that a meteor burns up in the Earth’s atmosphere. Most students assumed that a meteor flies past the Earth. These responses were grouped into the category “Flyby”. The idea that a meteor flies directly toward the Earth was mostly rejected. One student explained that its appearance in the night sky may give this impression: “So you can see from the Earth that it falls down like this, and then I would say that it’s not really towards the Earth, but more to the side.” (school1-7-1).

However, some students described the meteor as moving directly toward the Earth. These responses were grouped into the category Collision Course, which was coded in some cases. In addition, some students described the meteor as moving along a circular path, while others referred to a generally curved or bending path. In contrast, a straight flight path was also mentioned. Both Curved Path and Straight Path were coded in a few cases each. In many interviews, multiple subcategories related to the orbit of a meteor appeared. In some cases, it was even reported that the interview was the first time the student had consciously considered the flight path of a meteor (school1-7-1).

5.3.5. Observation (Functionality)

The question of where a meteor goes once it is no longer visible led to initial statements about its function. In many interviews, the students stated that the meteor either burns up or heats up. Also friction with the Earth’s atmosphere was mentioned as a cause for this, and in some interviews, the meteor’s speed was cited as a contributing factor. These three subcategories occurred in various combinations: some students logically explained the burning up of the meteor in the atmosphere as a result of its high speed (school1-9-9), while others referred to its speed as the sole explanation (school1-9-12).

Within the Observation category, several students also expressed ideas about a tail or trail. In a few cases, reasons were given for the presence of such a tail. For example, one student claimed that a meteor leaves a trail because it burns up (school1-7-5). In another interview, it was suggested that small fragments break off due to friction and form the tail (school1-9-2).

In a few interviews, the idea emerged that meteors are simply stars. One student described this as follows: “And basically, you would just see a normal star, I think. But at some point, the star falls down, so to speak.” (school2-7-9). In line with this interpretation, the same interviewee also positioned the flight altitude of the meteor at the level of the stars themselves.

6. Discussion

From the results of the interviews, several general conceptions could be extracted and add to the former findings obtained by Serttaş and Yenilmez Türkoğlu (2020) and Çevik and Kurnaz (2017). These are discussed separately for comets and meteors in the following subsections.

6.1. Gestalts of Comets and Meteors

Comets were frequently described as having bright tails, which were perceived as large enough to be visible from the Earth. The most common gestalt features identified were that the core of a comet is composed of rock with an irregular surface, often described as black or gray. Notably, ice was not mentioned as a constituent material, although this would align more closely with the scientific understanding. This absence may indicate conceptual confusion between the terms “asteroid”, “meteorite”, “meteor”, and “comet”, a confusion previously reported in the literature (see Korur, 2015). While the general scale of comets was usually understood as being large, specific size descriptions varied widely from the size of a tennis ball to that of Germany (approximately 357,000 km²). This indicates a lack of scale calibration.

Regarding the gestalt of meteors, they were typically described as either resembling a yellow or bright white star or appearing as a streak or line across the sky, occasionally with a sparkling quality. The former description may reflect a literal interpretation of the term “shooting star” (German: “Sternschnuppe”), which was used in the interviews. This common term may cause a metaphorical misunderstanding similar to those found in other mental models (e.g., for black holes; see Ubben et al., 2022, or Favia et al., 2014). Even students who reported having observed meteors still used these metaphorical descriptions, suggesting that the metaphor was a fitting match for their actual visual experience. Only a few students explicitly mentioned the observation of a tail. Most of their descriptions were less specific and reflected general impressions rather than detailed observations. A consistent finding was that meteors are visible only for a few seconds. This perception is likely grounded in direct experience and thus aligned with the observational reality.

6.2. Functionality of Comets and Meteors

Regarding the functional aspects of the mental models of comets, the tail was often mistakenly associated with processes such as burning or friction. Both explanations are scientifically inaccurate. When asked for elaboration, the students either attributed the glow of the comet to interaction with the atmosphere of the Earth or were unable to specify the mechanism, but still maintained a narrative of heat or burning causing the tail. In addition, some students described the comet’s trajectory as a straight line. Although this reflects visual perception during brief observations, it does not represent the actual orbital dynamics of comets. Of the few who described a circular path, none used the concept of an elliptical orbit. Instead, the Earth was often incorrectly identified as the center of this circular path, or no center was mentioned at all. Furthermore, students frequently assumed that comets were at a distance similar to that of the Moon, placing them far too close to the Earth relative to their actual position.

In the case of meteors, similar functional attributions were made, such as the ideas of burning and friction with the atmosphere. These explanations, while imprecise, suggest a rudimentary grasp of the phenomenon, since friction with the atmosphere is indeed responsible for the visible streak, though not through chemical burning in the strict sense. Thus, while the processes were often incorrectly described, the idea of chemical combustion was never explicitly associated with comets or meteors, which mirrors the findings in previous research on students’ conceptions of stars.

Descriptions of the reasons for the visibility of meteors generally approximated the correct ideas but lacked precision. For example, their “speed” was often cited as the cause of the tail. This is a vague explanation that hints at an understanding of the role of velocity but fails to connect it to frictional heating and atmospheric ablation in scientific terms.

Overall, all the students except one were able to articulate their ideas about both comets and meteors. The sole exception was a participant who explicitly stated that they had never thought about these phenomena before. This suggests that most students, even if only superficially, have formed conceptual models based on a combination of linguistic metaphors, media representations, and personal observations.

6.3. Limitations

The conclusions drawn from the data sample offer new insights into students’ thinking about comets and meteors. These findings represent the results of an initial exploratory and cataloging approach. However, several limitations must be considered when evaluating and discussing the dataset:

• Although several of the students’ statements pointed toward common conceptual difficulties related to comets and meteors, a more comprehensive evaluation would require a larger sample size. Only then could the frequency and distribution of the identified conceptions be reliably assessed. As such, the current findings are not generalizable but should be interpreted as examples of potential ideas that exist within the broader population. The quantitative information derived from the coding can, in the best case, serve as a rough orientation within the present sample.
• There are known connections between culture and pupils’ perceptions. For example, the typical linguistic usage of electricity consumption, which is almost always used in current media debates, can reinforce a corresponding idea that electricity is actually (partially) consumed by electrical components (e.g., Schecker et al., 2018). The same applies to other terms such as “horsepower” or “having an eye on something”, which can give rise to misconceptions due to the way the language is used. Therefore some of the misconceptions observed may stem directly from the metaphorical nature of the term “shooting star” itself. In German, the term used in the questions for meteors (“Sternschnuppe”) also contains the word star (“Stern”), which likely contributed to literal interpretations of the phenomenon. Stars are often depicted as white or yellow and jagged. However, the fact that the Sun is also a star may not necessarily be part of the typical knowledge of learners. We assume that similar metaphor-based misconceptions will be present among English-speaking students due to the shared terminology. However, further research is needed to assess whether these conceptions are also present in languages where the term for “shooting star” does not include the word “star”. To date, we have not encountered such examples. In particular in languages such as Japanese, Russian, Portuguese, Italian, Spanish, and French, the corresponding terms carry similar metaphorical implications, suggesting a cross-linguistic influence on conceptual understanding.
• It also appears that the ideas of the students were strongly influenced by representations in the media. The types of media students are exposed to and the frequency with which they engage with them vary significantly depending on their geographic location, cultural background, and social context. This introduces an additional layer of variability that should be taken into account in future studies aiming to generalize the findings between different populations.

6.4. Conclusions and Outlook

Although many of the participants reported having observed meteors either in real life or through the media, this was not the case for comets. Their ideas about meteors were generally somewhat more aligned with scientific explanations, while responses related to comets varied greatly and often lacked a foundational understanding. It remains unclear whether this difference stemmed solely from the fact that the students had experienced more prior exposure to meteors or whether other factors, such as media representation and the educational focus, played a role. Figure 3 summarizes what we believe to be the most important conceptions and misconceptions about comets and meteors that we found in this study.

Based on the data collected, we recommend that approaches to education on comets and meteors begin with a clear and structured introduction to their physical characteristics, particularly their scale, structure, and components. The essential aspects of the functions of comets and meteors should be clearly explained and compared on the basis of cause–effect relationships. Establishing this foundational knowledge may support students in constructing more scientifically accurate conceptions of comets and meteors and in distinguishing them from related astronomical phenomena such as asteroids.