Formative Assessment Probe

## Emmy’s Moon and Stars

This is the new updated edition of the first book in the bestselling Uncovering Student Ideas in Science series. Like the first edition of volume 1, this book helps pinpoint what your students know (or think they know) so you can monitor their learning and adjust your teaching accordingly. Loaded with classroom-friendly features you can use immediately, the book includes 25 “probes”—brief, easily administered formative assessments designed to understand your students’ thinking about 60 core science concepts.

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### Purpose

The purpose of this assessment probe is to elicit students’ ideas about the relative position of common objects seen in the night sky. The probe is designed to find out if students recognize how far away the stars are in relation to Earth and the Moon.

Sequencing

### Related Concepts

Earth-Moon system, stars, solar system, relative distances in the universe

### Explanation

The best response is A: There are no stars between Earth and the Moon. Even the Sun, which is the only star in our solar system, is located far beyond Earth and the Moon, not between it. The stars Emmy sees are located far away, outside our solar system. To put it all in perspective, the Sun is about 150 million kilometers (93 million miles) from Earth. The next nearest star is about 40 trillion kilometers (25 trillion miles) away. The Moon is only about 383,000 kilometers (238,000 miles) from Earth.

Distant stars, which are massive, appear as tiny points of light in the night sky because they are so far away. To a viewer on Earth, stars may seem closer because vast distances and enormous sizes in space are difficult to visualize. Agan (2004) described the difficulty in describing stellar distance this way:

The vast distances between stars are difficult for astronomers to discuss in common language. Many astronomy educators use scale models to provide a sense of the distances between stars. For instance, if the Sun were 1 inch in diameter, the nearest star would be nearly 500 miles away. A formal measurement of astronomical distances, the light year, is the distance that light travels in one year, approximately six trillion miles. The nearest star to the Sun, Proxima Centauri, is roughly 4.2 light years away. (p. 87)

### Curricular and Instructional Considerations

Elementary Students

In the early elementary years, students make regular observations of the night sky, taking inventory of the objects they see at night, including the Moon and stars. They are encouraged to draw what they see. The emphasis at this level should be on observing, describing, and looking for patterns. They learn how telescopes help us see more stars in the sky than we can with our eyes alone. In grades 3–5, students are developing an understanding of light and how it travels, and they begin to realize that the brightness of the light from objects very far away, such as stars, varies according to how far away the star is. They also notice that stars come in a variety of sizes and distances from Earth and the Sun. However, the magnitude of distance between objects in the night sky is still difficult for them to comprehend.

Middle School Students

Students at this level begin to add details to their model of objects in the solar system, extending out to the Milky Way galaxy and beyond. The crosscutting concept of scale is further developed, including much larger magnitudes and various methods and units of measurement for distant objects within and beyond our solar system. Students at this level use models to explain the apparent positions and movement of objects in the sky, including the solar system, stars, the Milky Way galaxy, and distant galaxies.

High School Students

High school is when a more complete picture of the vast universe develops. The study of the universe becomes more abstract. Huge magnitudes of scale make more sense to many students, although some are still at a level where abstractions and huge numbers are difficult to comprehend. Their knowledge of physics combines with astronomy to understand how the light spectra is used to determine distances from Earth.

### Administering the Probe

This probe can be used with students in grades 3–8. Ask students if they have ever looked up at the sky at night and seen the Moon and the stars. Be aware that some students who live in cities may have never seen the stars because of light pollution. It may help to have a photograph or picture that shows the Moon and stars as they would be seen if one looked at an evening sky in a dark location. If younger students are not yet familiar with the concept of a solar system, remove distracter E or describe the solar system as the place where Earth, other planets, and our Moon and Sun are found.

Related Disciplinary Core Ideas (NRC 2012; NGSS Lead States 2013)

K–2 ESS1.A: The Universe and Its Stars

• Patterns of the motion of the Sun, Moon, and stars in the sky can be observed, described, and predicted.

3–5 ESS1.A: The Universe and Its Stars

• The Sun is a star that appears larger and brighter than other stars because it is closer. Stars range greatly in their distance from Earth.

6–8 ESS1.A: The Universe and Its Stars

• Earth and its solar system are part of the Milky Way galaxy, which is one of many galaxies in the universe.

6–8 ESS1.B: Earth and the Solar System

• The solar system consists of the Sun and a collection of objects, including planets, their moons, and asteroids that are held in orbit around the Sun by its gravitational pull on them.

9–12 ESS1.A: The Universe and Its Stars

• The study of stars’ light spectra and brightness is used to identify compositional elements of stars, their movements, and their distances from Earth.

### Related Research

• It is a common belief among elementarygrade children that stars are smaller than the Moon and located in the solar system or around the Moon (Plummer, Kocareli, and Slagle 2014). Even when provided with instruction about the actual size of stars compared with planets and the Sun, children accept the idea that there are very large stars located very far away from our solar system but still hold on to the idea that there are also very small stars inside our solar system.
• Students’ grasp of many of the ideas about the composition and magnitude of the universe has to grow slowly over time. In spite of common depiction, the Sun-centered system seriously conflicts with common intuition (AAAS 2009).
• Agan (2004) interviewed high school and undergraduate college students to find out their ideas about distances between stars. Four out of eight high school students interviewed who had little astronomy instruction in their Earth science class and one undergraduate student out of five who received no formal astronomy instruction in high school or college described stars as being dispersed within the realm of the solar system.
• Dussault (1999) reported on a survey of 257 visitors to the Smithsonian National Air and Space Museum in Washington, D.C., who were asked to name things found in the solar system. As expected, 82% named planets; surprisingly, 41% named stars and 18% named galaxies. Just 5% of the visitors named Earth as a component of the solar system.
• Field-testing this probe with 64 fifth graders who had previously learned about the solar system revealed the following responses: 19% chose A, 15% chose B, 41% chose C, 10% chose D, and 15% chose E (Keeley 2011).

### Related NSTA Resources

Keeley, P. 2011. Formative assessment probes: Where are the stars? Science and Children 49 (1): 32–34.

Keeley, P. 2014. Where are the stars? In What are they thinking? Promoting elementary learning through formative assessment, P. Keeley, 69–76. Arlington, VA: NSTA Press.

Plummer, J. D. 2017. Core idea ESS1: Earth’s place in the Universe. In Disciplinary core ideas: Reshaping teaching and learning, ed. R. G. Duncan, J. Krajcik, and A. E. Rivet, 185–203. Arlington, VA: NSTA Press.

Wiebke, H., M. Rogers, and V. Nargund-Joshi. 2011. Sizing up the solar system. Science and Children 49 (1): 36–41.

### Suggestions for Instruction and Assessment

• This probe can be combined with the probe “What’s Inside Our Solar System?” in Uncovering Student Ideas in Astronomy to see if students distinguish between objects that are found in our solar system and objects outside the solar system (Keeley and Sneider 2012).
• This probe can be used to elicit students’ ideas about where stars are located after students have developed a model of where Earth, the Moon, and the Sun are relative to each other.
• Encourage younger children to draw what they see in the night sky and talk about how near or far away those objects are.
• Fiction books children read at this age can contribute to the development of an incorrect model of the night sky. Some of these books include illustrations that show a star within the curve of a crescent Moon (which means the star is in front of the Moon and nearby) or show stars that are greatly distorted in size compared with the Moon.
• Show students an image of a night sky with a crescent Moon and several stars in the sky, including one that is inside the curve of the crescent. Challenge students to figure out what is wrong with the picture and why.
• Some ideas about light and sight need to be developed before children can understand astronomical phenomena. Develop the idea that a large light source seen at a great distance looks like a small light source that is much closer. This phenomenon should be observed directly outside at night or with photographs (AAAS 2009).
• Keep in mind that students’ understanding of the magnitude of the universe needs to develop slowly over time. Numbers like billions and trillions, even millions, do not make much sense to young children because the vast scale is too abstract to comprehend. Even adults have difficulty comprehending how large a billion is.
• Begin developing the crosscutting concept of scale distance with familiar objects that students can see in the sky, such as the clouds, Moon, and Sun. Gradually introduce the nearby planets and then planets that are farther away. Once students are at a conceptual level where they can grasp the enormity of our solar system, introduce the distance between Earth and nearby stars outside our solar system in the Milky Way galaxy, gradually working outward to vast distances beyond our galaxy when students are ready to comprehend the magnitudes and measurement systems involved.
• Using telescopes—or even a good pair of binoculars—instead of the naked eye reveals more stars and makes the stars seen with the naked eye seem much brighter. Link the idea of stars being seen as points of light very far away with how telescopes help us see things, such as stars, better at significant distances. However, students need to be aware that the distance between Earth and the stars cannot be determined with the eyes alone.
• Middle school is a good time for students to create a model of the solar system using the same scale for both size and distance. Several modeling activities are available online, including PBS Learning Media’s “Earth as a Peppercorn” model at https://ri.pbslearningmedia. org/resource/mck14-pd-sci-ess-peppercorn/ earth-as-a-peppercorn.
References

Agan, L. 2004. Stellar ideas: Exploring students’ understanding of stars. Astronomy Education Review 3 (1): 77–97.

American Association for the Advancement of Science (AAAS). 2009. Benchmarks for science literacy. New York: Oxford University Press. www.project2061.org/publications/bsl/online/ index.php.

Dussault, M. 1999. How do visitors understand the universe? Studies yield information on planning exhibitions and programs. ASTC Newsletter (May/June): 9–11.

Keeley, P. 2011. Formative assessment probes: Where are the stars? Science and Children 49 (1): 32–34.

Keeley, P., and C. Sneider. 2012. What’s inside our solar system? In Uncovering student ideas in astronomy: 45 new formative assessment probes, P. Keeley and C. Sneider, 147–152. Arlington, VA: NSTA Press.

National Research Council (NRC). 2012. A framework for K–12 science education: Practices, crosscutting concepts, and core ideas. Washington, DC: National Academies Press.

NGSS Lead States. 2013. Next Generation Science Standards: For states by states. Washington, DC: National Academies Press. www.nextgenscience.org.

Plummer, J. D., A. Kocareli, and C. Slagle. 2014. Learning to explain astronomy across moving frames of reference: Exploring the role of classroom and planetarium-based instructional contexts. International Journal of Science Education 36 (7): 1083–1106.