1-ESS1-1: Sun, Moon, and Stars – Observing and Predicting Patterns in the Sky

General Overview

Performance Expectation – 1-ESS1-1: Use observations of the sun, moon, and stars to describe patterns that can be predicted.
Clarification Statement: Examples of patterns could include that the sun and moon appear to rise in one part of the sky, move across the sky, and set; and stars other than our sun are visible at night but not during the day.
Assessment Boundary: Assessment of star patterns is limited to stars being seen at night and not during the day.

Human beings have been watching the sky since before recorded history. Ancient astronomers used the movements of the sun, moon, and stars to navigate oceans, plant crops, schedule ceremonies, and understand their place in the cosmos. These celestial patterns – so reliable that civilizations built entire calendars around them – are the same patterns that first-grade students can begin to observe, describe, and predict today.

1-ESS1-1 is the first formal introduction to astronomy in the NGSS sequence, and it is beautifully grounded in direct observation rather than abstract explanation. First graders are not expected to understand why the sun rises in the east – they are expected to observe that it does, consistently and predictably, and to recognize that this regularity is itself a scientific finding worthy of documentation. The disciplinary core ideas come from ESS1.A (The Universe and Its Stars) and ESS1.B (Earth and the Solar System). ESS1.A establishes that the universe contains many objects including stars and that patterns of their apparent motion can be observed and predicted. ESS1.B introduces the idea that Earth’s position and motion in the solar system explains many of the patterns we observe – though at Grade 1, the explanatory mechanisms (Earth rotating on its axis, orbiting the sun) are not yet required. The focus is on the patterns themselves: reliable, repeated, and predictable.

The science and engineering practice is Analyzing and Interpreting Data: students collect firsthand observations over time and look for recurring patterns. The crosscutting concept is Patterns – patterns in the natural world can be observed, described, and predicted. When a first-grader says “The sun always seems to come up on the same side of the sky every morning,” they have made a genuine scientific observation and identified a pattern. There is also a profound connection to Scale, Proportion, and Quantity – the sun, moon, and stars are unimaginably large and distant, yet we observe them as small objects in the sky. Introducing students to this scale discrepancy plants seeds for later astronomical understanding.

This standard investigates sky patterns at two complementary timescales. The daily timescale captures the sun’s apparent arc across the sky from east to west and the corresponding change in shadow length and direction throughout a single day. The monthly timescale captures the moon’s changing phase over approximately 29.5 days and the moon’s own nightly arc across the sky. Stars sit at both timescales – they arc nightly just as the sun does, but the key Grade 1 observation is simply that they are visible at night and not during the day.

For teachers, the most important conceptual distinction to hold is between the apparent motion of sky objects (what we observe from Earth) and the actual motion (Earth rotating). At Grade 1, use careful language: “The sun appears to rise in the east” and “From where we stand, we see the sun move across the sky.” This language is accurate and leaves room for the deeper explanation students will receive in Grade 5 without planting an incorrect geocentric model.

Scope and Sequence

What Comes Before (Kindergarten)

In kindergarten, students observed and recorded local weather patterns (K-ESS2-1), which involved looking at the sky for clouds and precipitation. They also investigated how sunlight warms Earth’s surface (K-PS3-1), establishing the sun as a heat and energy source. These experiences give first graders an important foundation: they know the sun warms things and that sky conditions change day to day. Now they will look more systematically at what the sun, moon, and stars actually do across predictable time cycles – moving from qualitative weather description to quantitative pattern detection in astronomical phenomena.

At This Grade Level (Grade 1)

Students develop four core understandings through direct investigation: (1) the sun appears to rise in the east each morning, move in an arc across the sky throughout the day, and set in the west each evening – every day without exception; (2) shadows change direction and length throughout the day as a direct reflection of the sun’s position, with the shortest shadows at noon when the sun is highest; (3) the moon also moves across the sky in a similar east-to-west arc, and its visible shape changes over the course of approximately 29.5 days in a predictable, repeating cycle; (4) stars are visible in the night sky but not during the day because the sun’s brightness overwhelms their much dimmer light. Throughout, students practice the observation, recording, and pattern-identification skills that are the foundation of all scientific inquiry.

What Comes After

Standard 1-ESS1-2 (taught alongside this one) directly extends this work to examine how the amount of daylight changes across seasons – a consequence of Earth’s orbital motion that students discover through data. In Grade 5 (5-ESS1-2), students revisit shadows formally: they represent data on daily and seasonal changes in shadow length and direction in graphical displays and begin to construct models of Earth’s rotation to explain the patterns. In middle school (MS-ESS1-1), students develop and use quantitative models of the Earth-sun-moon system to explain lunar phases, eclipses, and seasons. In high school, students build mathematical models of orbital mechanics and analyze light from distant stars to understand the universe’s composition and history. The observational foundation of Grade 1 is the conceptual anchor for all of this increasingly sophisticated understanding – students who have actually watched the sun move and traced their own shadows are far better positioned to understand why those things happen when the mechanism is finally taught.

What Students Must Understand

The Sun’s Daily Pattern

Every day without exception, the sun appears to rise in the east, move gradually across the sky from east to west, and set in the west. The sun is highest in the sky around midday – this is when shadows are shortest, because the sun shines most steeply downward. In the morning and afternoon, the sun is lower on the horizon and shadows are much longer. This daily pattern repeats reliably and can be used to tell approximate time and direction – the same principle behind the sundial, one of humanity’s oldest tools. Students must understand that from their perspective on the ground, the sun traces a predictable arc, and that this arc is consistent from one day to the next (though its height changes across seasons, connecting to 1-ESS1-2). The practical application is powerful: if you know it is morning, you can predict the sun will be in the east; if your shadow is very short, you can infer it is close to noon.

Shadow Behavior

Shadows always point directly away from the sun – this relationship is precise and reliable. Morning shadows point west (sun is in the east); noon shadows point roughly northward (sun is in the south in the Northern Hemisphere); afternoon shadows point east (sun is in the west). Shadow length decreases as the sun rises and increases as the sun descends. A very short noon shadow means the sun is nearly overhead; a very long morning shadow means the sun is barely above the horizon. Students who understand this relationship can use shadows as a scientific instrument – reading the sun’s position from shadow behavior rather than from direct observation of the sun.

The Moon’s Patterns

The moon, like the sun, moves across the sky in an east-to-west arc each night (and sometimes during the day). Unlike the sun, the moon’s visible shape – its phase – changes over approximately 29.5 days in a predictable cycle: from new moon (not visible) to a thin waxing crescent, to first quarter (half-lit), to gibbous, to full moon, and then back through gibbous, last quarter, waning crescent, and new moon again. This cycle repeats reliably and can be predicted. Students in Grade 1 are not required to explain why phases occur – only to observe and describe the pattern. The Northern Hemisphere mnemonic is useful: when the lit portion resembles the letter D, the moon is waxing (growing); when it resembles the letter C, the moon is waning (shrinking). The moon can sometimes be seen during the day, especially in the waxing phase (afternoon/evening visibility) and the waning phase (morning visibility) – this surprises many students and directly addresses a common misconception.

Stars

Stars are objects in the sky that appear as tiny points of light at night. They are visible at night but not during the day – not because they go away, but because the sun’s light is so much brighter that it overwhelms the much dimmer light from distant stars. Our sun is itself a star – the closest one to Earth – which is why it appears so much larger and brighter than other stars. Stars appear to move across the sky at night in the same east-to-west direction as the sun and moon, a consequence of Earth’s rotation. Some stars appear to form patterns called constellations, which human cultures around the world have named and told stories about for thousands of years. At Grade 1, the key assessment boundary is simply: stars are seen at night and not during the day.

The Unifying Idea: Patterns Allow Prediction

Because the sun, moon, and stars follow consistent, repeating patterns, we can predict where they will be and what they will look like at different times. This is what astronomers do – and what ancient peoples did to create calendars, navigate oceans, and plan agricultural seasons. Pattern recognition is a fundamental scientific tool: noticing that something happens the same way repeatedly is the first step in understanding why it happens. Students should be able to articulate not just what a pattern is, but why patterns are useful: they let us make predictions and test those predictions against new observations.

Key Vocabulary

Sun, moon, star, sky, rise, set, east, west, north, south, pattern, predict, observation, arc, phase, crescent, full moon, half moon, waxing, waning, daylight, nighttime, horizon, shadow, appear, visible, constellation (enrichment).

Lesson Ideas and Activities

Activity 1: The Daily Sun Journal (Ongoing – Full Year)

Beginning in the first week of school, students make a brief sky observation each morning and afternoon to track the sun’s position. Each student receives a pre-printed journal template showing a sky arc from East (left) to West (right) with a horizon line and space for a small drawn sun. Students mark where the sun appears to be at the time of observation. The teacher adds compass labels to the classroom windows so students can orient their drawings correctly. After two weeks, arrange the morning observations in a row – students immediately see that the sun is always in the eastern part of the sky in the morning. Repeat for afternoon. Ask: “Is this a pattern? Can we predict where the sun will be tomorrow morning?” Weekly pattern discussions use accumulated data to deepen understanding. This investigation continues all year, with seasonal comparisons connecting directly to 1-ESS1-2.

Activity 2: Shadow Detectives – Three Times in One Day

On a sunny day, take students outside at three times: morning (~9 AM), noon (~12 PM), and afternoon (~2 PM). At a fixed, marked spot on the pavement, have one student stand while classmates trace the shadow with sidewalk chalk. Label each tracing with the time. Students observe and sketch each shadow in their journals, noting direction (which way it points) and length (short/medium/long). Back inside, create a class data table: “Time of Day / Shadow Direction / Shadow Length / Sun Position.” Students answer: “Which shadow was longest? Shortest? What direction did each point? What does that tell us about where the sun was?” This investigation connects shadow behavior directly to the sun’s daily arc and produces visible, concrete data that first graders can analyze independently. Repeat at the same time of day across seasons to reveal the seasonal variation – noon shadows are dramatically longer in December than in September, a direct link to 1-ESS1-2.

Activity 3: The 30-Day Moon Observation Project

Launch this investigation just after a new moon so students observe the complete cycle. Each student receives a moon log booklet – one page per day, each page featuring a large pre-printed circle (their “moon canvas”), a date line, and checkboxes for “Observed,” “Cloudy,” or “Missed.” Every evening, students observe the moon with family members and shade their circle to show which portion is lit. Each morning, the class “Moon Reporter” shares their observation, and the drawing is added to the large class moon calendar on the wall. Weekly pattern discussions ask: “Is the moon getting bigger or smaller? What do you predict it will look like next week?” After 29–30 days, the complete calendar reveals the full cycle. Students count the days from new moon to new moon, discover the ~29-day period, and make predictions about future moon phases. Send a family letter home at the start explaining the project, including tips for cloudy nights (note it and skip, use a moon phase app, or interpolate from surrounding nights). This is one of the most family-friendly investigations in all of elementary science – many families report it becomes a treasured nightly ritual. Use the “D and C” mnemonic: when the lit part looks like a D, the moon is growing (waxing); when it looks like a C, the moon is shrinking (waning).

Activity 4: Stars – Day and Night Simulation

Darken the classroom as much as possible and place several small LED tea lights or glow-in-the-dark stickers on the ceiling and walls to represent stars. Turn off all classroom lights so the “stars” are clearly visible. Then shine a very bright flashlight or turn on a strong lamp representing the sun. Students immediately observe that the bright light washes out the dim star lights – they can no longer see the “stars,” but those lights are still physically present. Turn the bright light off (“sunset”) and the stars become visible again. Ask: “Did the star lights disappear? Are they still there? Why couldn’t we see them? What does this tell us about why we can’t see real stars during the day?” This activity directly and experientially addresses the extremely common misconception that stars “go away” during the day and provides students with a physical model they can return to mentally when discussing this phenomenon.

Activity 5: Sun Path Dramatization

Students act out the sun’s apparent daily journey. Mark East and West on opposite sides of the classroom or gymnasium. One student stands in the center representing an observer on Earth. A second student (or a ball on a string) slowly walks in a low arc from East to West, representing the sun’s apparent path across the sky. Ask the “Earth” student: “What do you see? Where does the sun start? Where does it end? When is it highest? When is it lowest?” Switch roles so all students experience both perspectives. Connect to the journal: “This is exactly what your sun journal shows – the sun always moving from East to West in the same arc.” Extend to the moon: have a student walk the same arc but at different speeds and with different starting times to show that the moon follows the same general path but on its own schedule and is sometimes visible during the day depending on phase.

Activity 6: Constellation Stories – Culture, History, and Pattern Recognition

Show students a simple star map of a few easily recognizable constellations visible from your location (Orion, the Big Dipper, Cassiopeia, Scorpius depending on season). Explain that for thousands of years, people all over the world found patterns in the stars and told stories about them. Read a picture book featuring star stories from different cultures – “Zoo in the Sky” by Jacqueline Mitton, “The Stars” by H.A. Rey, or “Thirteen Moons on Turtle’s Back” by Joseph Bruchac for Indigenous moon/star traditions. Ask: “Why might different cultures have given names to star patterns? How could knowing star patterns help a sailor crossing the ocean at night? How could they help a farmer know when to plant?” If a clear night visit is possible (school event, planetarium trip, or homework with families), have students look for one target constellation and draw it. Even one successful naked-eye constellation observation at age six or seven can be a lifelong memory. This activity honors the diversity of human astronomical traditions and connects science to history, culture, literature, and navigation.

Activity 7: The Sun, Moon, and Stars Comparison Chart

Build a three-column class anchor chart collaboratively over several weeks as students accumulate observations. Columns: Sun / Moon / Stars. Rows: “When do we see it?” / “Where in the sky does it appear?” / “Does it move?” / “Does it change shape or appearance?” / “How bright is it?” / “Can we predict where it will be?” The critical pedagogical move is NOT filling this in on Day 1 from prior knowledge – instead, leave cells blank and fill them in as student investigations produce evidence. When a student observes the moon during the day and reports it, the class can update the “When do we see it?” row for the Moon. When the shadow investigation reveals the sun’s east-to-west movement, update the Sun column. The chart becomes a living document of student-generated scientific knowledge, and the process of building it with evidence rather than simply being told the answers models authentic scientific practice.

Common Student Misconceptions

Misconception 1: “The sun moves around Earth.”

This is the most historically durable misconception in all of astronomy – the geocentric view that the sun orbits Earth. It is perfectly consistent with what we observe from Earth’s surface and was the scientific consensus for most of human history. At Grade 1, teachers should not attempt to correct this by teaching Earth’s rotation – that comes in Grade 5 when students have the spatial reasoning to process it. Instead, use consistently careful language: “The sun appears to move across the sky” and “From where we stand, we see the sun rise in the east.” This language is scientifically accurate and leaves room for the later revelation without planting the incorrect geocentric model. If students say “the sun moves,” gently rephrase: “You’re right – it looks like it moves! Scientists say it appears to move across the sky.”

Misconception 2: “Stars go away during the day.”

Because stars are invisible during the day, many children assume they disappear or travel somewhere else when the sun comes up. The idea that they are always present but simply overwhelmed by the sun’s brightness is non-obvious and counterintuitive. The Day/Night Simulation activity (Activity 4) directly and experientially addresses this – students watch “stars” disappear when a bright light is turned on and reappear when it is turned off, never doubting that the lights are still physically there. Also use the analogy: “If someone shines a spotlight directly in your face in a dark room, can you see the small flashlight on the other side of the room? The small flashlight didn’t go away – you just can’t see it through the spotlight. That’s what the sun does to stars every morning.”

Misconception 3: “The moon is only visible at night.”

Most children have a firm mental model of “sun = daytime, moon = nighttime.” In fact, the moon is visible in the daytime sky roughly half of each month. During the waxing phase (first half of the lunar cycle), the moon is visible in the eastern sky in the afternoon and the western sky in the early evening – sometimes clearly during the school day. Have students watch for the daytime moon. When one is spotted, celebrate it as a scientific discovery and use it to update the class anchor chart. Ask: “If the moon is visible right now during the day, where will it be tonight? Tomorrow morning?” This not only corrects the misconception but gives students rich observational practice connecting phase and visibility timing.

Misconception 4: “Moon phases are caused by Earth’s shadow falling on the moon.”

This is among the most common misconceptions in all of elementary and middle school astronomy – it affects a significant percentage of adults as well as children. It arises from reasonable but incorrect reasoning: students know shadows can change shape, they know Earth is between the sun and moon sometimes, and they incorrectly combine these ideas. What students are describing is actually a lunar eclipse (which occurs only a few times per year), not the monthly phase cycle. At Grade 1, students are not required to explain phases – only to observe the pattern. If students offer the “Earth’s shadow” explanation, respond warmly: “That’s a really thoughtful idea! Scientists actually discovered that it works differently – but we’ll learn the real explanation when we’re older. For now, let’s focus on what we actually see: the pattern of the moon’s shape changing every month.” Do not teach the incorrect mechanism; do not yet teach the correct one – focus on the observable pattern.

Misconception 5: “The sun and moon are the same size.”

From Earth, the sun and moon appear almost identical in size – a remarkable coincidence that makes total solar eclipses possible. Students may assume they are actually the same size. Demonstrate scale with a basketball (representing the sun) held across the room and a marble (the moon) held close – point out that the basketball looks smaller than the marble from this distance even though it is vastly larger. The sun is approximately 400 times wider than the moon, but it is also approximately 400 times farther away, making them appear the same size from Earth. This is an extraordinary coincidence, and students find it genuinely fascinating. Use this to plant the seed of the concept of apparent size vs. actual size – a precursor to understanding astronomical scale.

Misconception 6: “The moon makes its own light.”

The moon appears to glow brightly, so students naturally assume it produces its own light as the sun does. In reality, the moon is a rocky, airless body that has no ability to produce light – it only reflects sunlight. Ask: “Has anyone ever seen the moon during the day? If the moon made its own light, would we expect to see it in the daytime sky?” Use a demonstration: darken the room, hold a matte ball (representing the moon), and shine a flashlight (the sun) on it. The ball “glows” from the reflected flashlight, not from itself. Block the flashlight and the ball is dark. This directly shows the reflection principle and also introduces the concept that the moon’s phase is related to where the sunlight is hitting it from – a seed for the later explanation of phases.

Misconception 7: “Shadows are longest at noon.”

Some students assume that noon is when shadows are largest because noon is the peak of the day. The shadow investigation directly and empirically refutes this. Before conducting the investigation, ask students to predict: “When do you think shadows will be longest – morning, noon, or afternoon?” Record predictions. After the investigation, compare results to predictions. Students who predicted “noon” and discover they were wrong will remember the correct answer (noon = shortest shadows, sun is highest) far more durably than students who were simply told. This is an excellent example of using investigations to productively challenge misconceptions rather than correcting them through direct instruction.

Assessment Questions

Recall and Observation

1. Where does the sun appear to be in the sky in the morning? Where is it in the afternoon? Where does it go at the end of the day?
2. Is the sun’s pattern the same every day, or does it change? How do you know?
3. Can you see stars during the day? Why or why not?
4. Describe what the moon looked like the last time you saw it. Does it always look that way?
5. When is your shadow the shortest during the day – morning, noon, or afternoon? Why?

Pattern Recognition and Prediction

6. (Show a diagram of the sun at three positions in the sky – low-east, high-middle, low-west.) Which picture shows the sun in the morning? Which shows it at noon? Which shows it in the afternoon? How do you know?
7. It is Monday morning and the sun is just rising. Where do you predict the sun will be at lunchtime? After school? Tonight? Why?
8. (Show a drawing of a waxing crescent moon.) What did the moon look like about one week ago? What do you think it will look like in about one week? In about two weeks? How do you know?
9. Look at our 30-day moon calendar. What pattern do you see? How long does it take for the pattern to repeat? What will the moon look like on this same date next month?

Evidence-Based Reasoning

10. A classmate says “Stars disappear during the day.” Do you agree or disagree? What evidence would you use to support your answer?
11. Another student says the moon only comes out at night. Is this always true? When might you see the moon during the day? How do you know?
12. We traced shadows at three times today. Which shadow told you where the sun was highest? How did the shadow point tell you which direction the sun was?
13. A student just moved to our school from another town. They say “I have never noticed the sun always coming up in the same place.” What would you tell them? What evidence from our investigations would you share?

Connections and Application

14. Ancient sailors used the stars to find their way across the ocean at night. What would need to be true about star patterns for this to work? Why are patterns important for navigation?
15. If you were standing outside on a sunny day with no clock or phone, how could you use the sun or shadows to estimate the time of day? What would you need to know?
16. Draw the sky at three different times in one day: early morning, noon, and late afternoon. Show where the sun would be in each drawing. Draw what your shadow would look like at each time. Label each picture with the time of day and the direction the shadow points.
17. Why do scientists say the movements of the sun, moon, and stars are “patterns”? Why does it matter that they follow patterns – what can we do with that information?