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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The purpose of this assessment probe is to elicit students’ ideas about the day/night cycle. The probe is designed to determine whether students recognize that Earth’s rotation explains why it is dark at night and light during the day.

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Day/night cycle, rotation

The best answer is Talia’s: Earth spins completely around once a day. The reason for the day/night cycle is that Earth spins completely around on its axis approximately every 24 hours. When our location on Earth is turned away from the Sun, we have night (darkness). When our location on Earth is turned toward the Sun, we have day (daylight).

Elementary Students

In the early primary years, students recognize that there is a repeating pattern of daytime and night, and that the amount of daylight changes throughout the year. At first, this is primarily observational with a focus on patterns. Observations of the Sun’s location make it look to them as if the Sun is the body that is moving, but it is important for students to trace this movement before introducing rotation. By third grade, students begin to learn about Earth’s motion to explain patterns. Now they can use models to move beyond their own location-based perspective to describe and explain how Earth’s rotation causes the day/night cycle. It is also important to make sure students have a concept of a spherical Earth before using models to explain Earth’s rotation. Gradually, the terms rotation and Earth’s axis are introduced when students are ready to link the concept to the phenomenon.

Middle School Students

Students’ understanding of the day/night cycle expands to include ideas about the effect of Earth’s tilt and the changing position of the Sun in the sky during different times of the year. They can look at patterns of sunrise and sunset and begin to recognize that the length of day (photoperiod) changes during different times of the year and with different locations on Earth. However, the orbital geometry involved in understanding this concept is still challenging. Students at this level may often confuse rotation with revolution.

High School Students

During high school, more complex and quantitative ideas about the Earth-Moon-Sun system are developed, along with the idea that other planets and their moons rotate at different speeds and have day/night cycles of varying lengths. They also examine changes in the tilt of Earth’s axis of rotation over a large time scale.

This probe can be used with students in grades 3–8. Terminology like rotation, spinning on an axis, and revolution are intentionally avoided to probe for conceptual understanding. Make sure students understand that night refers to the period of darkness when the Sun is not visible and that day refers to the period of daylight when the Sun is visible in the sky. Don’t assume that older students can explain this phenomenon.

• Explanations of the day/night cycle, the phases of the Moon, and the seasons are very challenging for students. To understand these phenomena, students first should master the idea of a spherical Earth, itself a challenging task (AAAS 2009).
• The two most common alternative conceptions are that the day/night cycle is caused by Earth going around the Sun once a day and that it is caused by the Sun going around Earth once a day (Danaia and McKinnon 2007).
• Because the explanation for the daily cycle of light and dark has traditionally been taught at the early elementary grades, some researchers have attempted to teach the concept as early as preschool (ages 5 and 6). However, they have had little success (Valanides, Gritsi, and Kampeza 2000).
• Mant and Summers (1993) interviewed primary school teachers in England. Although most could explain the day/night cycle in scientific terms, few could relate their explanations to observations of how the Sun appears in the sky. Some appeared to work backward from their explanation to describe what must be happening in the sky. That suggests it is important to have students first observe how the Sun changes its position during the daytime, before explaining why that happens from the viewpoint of a spinning Earth.
• Some students at the secondary level may still believe that day and night occur because Earth goes around the Sun or the Sun goes around Earth (Schoon 1992).
• An older study by Baxter (1989) identified six ideas about day and night and showed that students, starting in preschool, seem to move through these ideas as they get older: (1) the Sun goes behind the hills, (2) clouds cover the Sun, (3) the Moon covers the Sun, (4) the Sun goes behind Earth once a day, (5) Earth goes around the Sun once a day, and (6) Earth spins on its axis once a day.

Bogan, D., and D. Wood. 1997. Simulating Sun, Moon, and Earth patterns. Science Scope 21 (2): 46–48.

Haverly, C., and K. Sedlmeyer. 2019. Making sense of day and night. Science and Children 56 (9): 28–37.

Morgan, E. 2013. Next time you see a sunset. 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.

• The probes “What Causes Night and Day?” and “Where Did the Sun Go?” in Uncovering Student Ideas in Astronomy can be used to further elicit students’ ideas about the day/night cycle (Keeley and Sneider 2012b, 2012c).
• When revisiting this probe a second time and after students have had an opportunity to learn about the day/night cycle, make the probe three dimensional by (1) asking students to describe a model they could use to explain their answer choice and (2) including the crosscutting concept of patterns in their explanation.
• Make sure elementary students accept the idea of a spherical Earth, which is a precursor to understanding the spin of Earth on its axis. Because they visualize a flat, solid Earth beneath their feet, it is a transition for students to visualize Earth as a huge ball in space. Primary grade students should also develop the idea of a repeated pattern of day/night before being expected to explain what causes the pattern.
• Use physical models made from common objects, such as a globe and a flashlight, to help students visualize the phenomenon of day and night experienced from different locations on Earth. Make sure students have the opportunity to manipulate their models rather than being passive observers of a teacher demonstration.
• Globe models can be followed by having students simulate the spinning Earth with their heads. Have the students slowly turn in place to see the “sunrise” as they just start to see the light, then have them observe how the Sun goes from one side of their field of view to the other side until they finally see “sunset” as the Sun disappears on the other side of their view.
• Students (and even adults) often confuse the terminology related to Earth’s motion. Introduce rotation before revolution. Start with the concept of an Earth spinning about an axis before introducing the terminology. Once students have grasped the idea of rotation, use a model to help them see that Earth rotates as it moves around the Sun in a nearly circular path.
• Help students recognize how our everyday language may lead to incorrect ideas about the day/night cycle. Have students critique the use of words and phrases like sundown, sunrise, the Sun is sinking, the Sun comes up in the morning, and sunset.
• Older students may know that Earth spins on its imaginary axis, but they may have never been asked to describe what direction Earth spins in—clockwise or counterclockwise, east to west, or west to east? Challenge students to figure it out based on their observations of sunrise and sunset.
• Use the crosscutting concept of patterns with upper elementary or middle school students to analyze how and figure out why sunrise and sunset times differ throughout the year, especially in higher latitudes.
• Middle and high school students can use the probe “How Long Is a Day on the Moon?” in Uncovering Student Ideas in Astronomy to elicit their ideas about the day/night cycle on the Moon and develop a model to explain it (Keeley and Sneider 2012a).