Performance Expectation
K-PS3-1. Make observations to determine the effect of sunlight on Earth’s surface.
Clarification Statement: Examples of Earth’s surface could include sand, soil, rocks, and water.
Assessment Boundary: Assessment of temperature is limited to relative measures such as warmer/cooler.
General Overview
The sun is the engine of Earth’s climate, weather, ecosystems, and life itself. Almost all energy on Earth ultimately comes from the sun – the light that warms our skin, the wind that bends the grass, the coal that powers our electricity grid, the food we eat for breakfast. Understanding the sun as Earth’s primary energy source is one of the most foundational ideas in all of earth and space science, and K-PS3-1 plants that seed in kindergarten through the simplest possible observation: does sunlight make things warmer?
This investigation is a masterclass in the NGSS science and engineering practice of Planning and Carrying Out Investigations. Students don’t just read about sunlight warming things – they design and conduct a simple comparison: place identical materials in sunlight vs. shade and observe the temperature difference. This is a genuine, if simple, scientific investigation: identifying a variable (sunlight/shade), holding other factors constant (same type of material, same starting conditions), making systematic observations, and drawing conclusions from data.
The crosscutting concept is Cause and Effect – one of the most powerful and pervasive organizing concepts in science. Sunlight causes Earth’s surface to warm. This simple causal relationship, when thoroughly understood by a five-year-old, is the first link in a long chain of understanding that eventually includes the greenhouse effect, the water cycle, wind formation, and global climate systems.
Although K-PS3-1 is classified as a physical science standard (PS3 = Energy), it is deeply earth science in content and should be taught in close connection with K-ESS2-1 (Weather Patterns). The sun’s differential heating of Earth’s surface is the physical mechanism behind most weather – students who understand PS3-1 are far better equipped to understand why weather is what it is.
Scope and Sequence
What Comes Before
Most kindergartners have experienced the warmth of the sun on their skin and know intuitively that sunny days are warmer than cloudy days. However, few have made systematic observations of how sunlight affects specific materials differently, and fewer still have connected this to the mechanisms of weather and climate.
At This Grade Level
Students learn through direct investigation that:
- Sunlight makes Earth’s surface materials (sand, soil, rock, water) warmer;
- Without sunlight, these materials are cooler;
- The sun is a heat source for Earth;
- Different materials may warm at different rates in the sun.
What Comes After (K-PS3-2)
K-PS3-2 (taught alongside K-PS3-1) extends this investigation to engineering: how can we design a structure to reduce the warming effect of sunlight on an area? This is the engineering companion to the science investigation here – understanding the problem (sunlight warms surfaces) leads directly to designing solutions (shade structures, reflective materials).
Connections to Later Earth Science
- In Grade 4, students examine how the sun affects Earth’s water cycle and the transfer of energy through Earth’s systems.
- In Grade 5, students build a full model of Earth’s energy budget.
- In middle school, students investigate electromagnetic radiation, the greenhouse effect, and climate modeling.
- The causal understanding developed in this kindergarten investigation – sunlight warms surfaces – is the first step in a 13-year learning progression about Earth’s energy system.
What Students Must Understand
- The sun shines light and energy on Earth. This energy warms Earth’s surface.
- When sunlight hits the surface of sand, soil, rocks, or water, those materials get warmer. In the shade (away from direct sunlight), they stay cooler.
- The sun is Earth’s main source of heat and energy. Without the sun, Earth would be dark and very, very cold.
- Different materials on Earth’s surface (sand, water, soil, rock) can feel different temperatures even when exposed to the same amount of sunlight – some warm up faster than others. (This differential heating is responsible for wind and weather patterns, though the mechanism is not expected at this level.)
- Scientists observe and compare to discover cause-and-effect relationships. By observing that things in the sun are warmer than things in the shade, we can determine that sunlight causes warming.
Key Vocabulary
Sunlight, sun, energy, heat, warm, cool, shadow, shade, surface, observe, observation, compare, cause and effect, temperature, sand, soil, rock, water.
Lesson Ideas and Activities
Activity 1: The Core Investigation – Sunlight vs. Shade
Overview: The heart of this standard is a simple, replicable investigation. Students compare the temperature (using qualitative touch-based measures: warmer/cooler) of surface materials placed in sunlight versus identical materials placed in shade.
Materials: Two identical containers per material; sand, soil, small rocks, water; outdoor space with both sunny and shaded areas; optional: digital instant-read thermometers for precise measurement (though qualitative observation is sufficient for assessment).
Procedure:
- Place identical amounts of sand, soil, rock, and water in pairs of containers. Leave one set in direct sunlight and one set in complete shade for 20–30 minutes.
- Students touch (carefully) the surface of each material and compare: warmer or cooler?
- Record observations on a class chart: “In the Sun” / “In the Shade” – warmer or cooler?
- Discuss: “What caused the difference? Was it the material? The color of the container? What was the one thing that was different between the two groups?”
Guiding the Variable Analysis:
Ask: “We had two containers of sand. What was different about them? What was the same? So the only difference was ___. What does that tell us about what caused the temperature difference?”
Safety Note: On a very hot day, sand and dark rocks in direct sunlight can get hot enough to burn. Always check surface temperatures before having students touch materials. Consider using the back of the hand rather than fingertips for safety.
Activity 2: Shadow Tracing – Where Does the Sun Put Its Energy?
Overview: Students observe and trace shadows at different times of day (morning, noon, afternoon) to see how the sun’s position changes. Connect this to the observation that when the sun is higher and more directly above us, surfaces warm faster.
Materials: Sidewalk chalk; a sunny outdoor space.
Procedure: One student stands in the same spot at 9 AM, noon, and 2 PM. Another student traces the shadow. Students compare: shorter shadows at noon = sun is more directly overhead = energy is more concentrated on a smaller surface area = surfaces warm faster.
Discussion: “Why do you think it’s usually warmest in the afternoon and not in the morning, even though the sun comes up in the morning?”
Activity 3: Dark vs. Light – Which Warms Faster?
Overview: Place identical materials (e.g., sand) in two identical containers, one painted black/dark and one painted white/light. Place both in sunlight. Compare temperatures after 15 minutes.
Learning Goal: Students discover that darker surfaces absorb more of the sun’s energy and warm up faster. This is relevant to understanding urban heat islands (dark pavement in cities) and climate feedback loops (dark ocean water absorbs more heat than white sea ice).
Discussion: “Why do people in hot countries often wear white or light-colored clothes? Why do houses in hot places often have white or light-colored roofs?”
Activity 4: Sunlight and Plants – The Connection
Overview: Place two identical plants in identical conditions, with one in a sunny window and one in a dark closet. Observe over two weeks. Students observe that the plant in the sun stays healthy while the plant in the dark wilts and fades.
Discussion: “The plant without sunlight died (or got very sick). Why? What does the sun provide that the plant needs?” This bridges to K-ESS3-1 (natural resources) and seeds the concept of photosynthesis developed in later grades.
Activity 5: Build a Shade Structure (K-PS3-2 Engineering Extension)
Overview: Challenge students to design and build a small shade structure (using craft sticks, paper, tape, and other simple materials) that will keep a small container of sand cooler than an identical container left in direct sunlight.
Engineering Process: Ask (What is the problem?) → Imagine (How could we solve it?) → Plan (Draw the design) → Create (Build it) → Improve (Test and redesign).
Test: After 20 minutes in the sun, compare the shaded container to the unshaded control. Did the shade structure work? How could it be improved?
Common Student Misconceptions
Misconception 1: “The sun makes things warm because it is close to us.”
What students think: Children often believe that warm days happen because the sun is “closer” to Earth. This is incorrect – Earth’s distance from the sun varies only slightly, and winter/summer differences in temperature are due to Earth’s axial tilt, not proximity.
How to address it: At the kindergarten level, you do not need to teach the full axial tilt concept. Simply acknowledge: “The sun is very, very far away – it doesn’t get closer in summer! But when the sun is higher in the sky during summer, its energy hits the ground more directly, which warms things up more.” This partial, accurate answer is developmentally appropriate.
Misconception 2: “The air is what gets warm from the sun – not the ground.”
What students think: Children often believe sunlight warms the air directly, not the ground first. In fact, solar radiation mostly passes through the atmosphere and warms Earth’s surface, which then radiates heat back into the lower atmosphere (this is the mechanism of the greenhouse effect).
How to address it: The investigation directly addresses this. Students observe that the ground surface (sand, soil, rock) becomes warm in sunlight. Extend the conversation: “What do you notice about how warm the air feels when you’re standing on hot pavement versus standing on cool grass? The warm ground heats the air above it.”
Misconception 3: “All surfaces warm up the same amount in the sun.”
What students think: Students may initially assume that sunlight affects all materials equally. The activity comparing different surfaces reveals that sand, soil, rock, and water warm at different rates – a phenomenon with profound implications for weather and climate.
How to address it: Ask students to touch dark pavement and nearby grass on a hot sunny day. The contrast is dramatic and memorable. Discuss: “Why does the pavement get so much hotter than the grass? What is different about them?” (Dark color; also water in the grass absorbs heat during evaporation.)
Misconception 4: “The sun goes away at night.”
What students think: Young children sometimes believe the sun disappears or ceases to exist at night, rather than understanding that night is caused by Earth rotating away from the sun.
How to address it: Earth’s rotation is not the focus of this standard, but you can plant a seed: “The sun is always shining – it shines on the other side of Earth when we are sleeping. Earth spins, so we face away from the sun at night. But the sun never goes away – it’s always there!”
Misconception 5: “Sunlight and temperature are the same thing.”
What students think: Students may not distinguish between light (electromagnetic radiation) and heat (thermal energy). They may believe bright light is the same as warmth.
How to address it: Use a counterexample: “Is the light from a flashlight as warm as sunlight? What about the light from a computer screen? Light and heat are related but not the same thing. Sunlight is special because it carries a lot of energy that warms things when it hits them.”
Assessment Questions
Observation and Investigation
- We put two containers of sand outside – one in the sun and one in the shade. What do you think we will find? Why?
- After the investigation: What did you observe? Which container was warmer? What caused the difference?
- What would happen if we moved the shaded container into the sun? What would happen if we moved the sunny container into the shade?
Cause and Effect
- What makes the sand on a beach feel so hot on a summer day?
- Why is the ground cooler in the early morning than in the afternoon?
- What would happen to Earth’s temperature if the sun stopped shining? How do you know?
Connections to Weather and Daily Life
- Have you ever noticed that your car seat feels very hot on a sunny day? What causes that?
- Why do you think deserts are so hot? What does the sun have to do with it?
- How does what we learned about sunlight and Earth’s surface connect to our weather observations? How does the sun affect weather?
Cross-Curricular Connections
Earth Science Integration
K-PS3-1 is the physical science mechanism behind K-ESS2-1 (weather patterns) and connects directly to K-ESS3-1 (living things need the sun’s energy, which plants capture through photosynthesis). Teach these standards in close proximity so students build an integrated understanding of how solar energy drives both the physical and biological world.
Engineering Design (K-PS3-2)
The understanding from K-PS3-1 directly motivates the engineering challenge in K-PS3-2: design a structure to reduce the warming effect of sunlight. This sequence (understand the phenomenon → design a solution) mirrors the real-world connection between science and engineering.
Mathematics
Measurement and comparison; data recording; simple graphs showing temperature comparisons across materials and conditions; time measurement (how long until the sand warms up?).
Teacher Background Knowledge
Solar Radiation: The sun emits energy in the form of electromagnetic radiation across a spectrum that includes ultraviolet (UV), visible light, and infrared radiation. When this radiation reaches Earth’s surface, it is absorbed and converted to thermal energy (heat). Different materials absorb and reflect solar radiation differently – dark materials absorb more; light materials reflect more. This property is called albedo.
Differential Heating: Land and water heat at very different rates. Sand and soil heat up quickly (low heat capacity) and cool quickly. Water heats slowly (high heat capacity) and releases heat slowly. This differential heating is a primary driver of sea breezes (cool air moves from ocean to land during the day as warm land air rises) and is ultimately responsible for much of Earth’s weather and climate variability. Knowing this is not expected of kindergartners, but teachers who understand it can make better connections and ask better questions.
The Greenhouse Effect (for teacher background): Solar radiation (mostly visible light) passes through the atmosphere relatively easily and warms Earth’s surface. Earth’s surface then radiates this energy back as infrared radiation (heat). Greenhouse gases in the atmosphere (CO2, water vapor, methane) absorb some of this outgoing infrared radiation and re-emit it in all directions, including back toward Earth’s surface. This “greenhouse effect” keeps Earth warm enough for life – without it, Earth’s average temperature would be about -18°C instead of the current 15°C. Human activities are enhancing this effect by adding CO2 and other greenhouse gases to the atmosphere. This mechanism is taught explicitly in grades 7–12, but the first link – sunlight warms Earth’s surface – is established here in kindergarten.