Groundhog Day STEM Challenge: Exploring Shadows, Light & Weather Predictions with Free STEM Worksheets

Groundhog Day STEM challenge is perfect for blending science, engineering, and critical thinking into fun, hands-on learning experiences! While some classrooms focus on the groundhog’s prediction, we decided to take a STEM-inspired approach—exploring shadows, engineering, and even weather forecasting.

Whether you’re a teacher, parent, or even homeschooler parent looking for meaningful activities, these  Groundhog Day STEM challenges will get kids thinking, experimenting, and having a blast! And yes, don’t forget to grab your free STEM worksheets and task cards at the bottom to make planning a breeze.

Groundhog Day STEM Challenge: Exploring Shadows, Light & Weather Predictions with  Free STEM Worksheets

Groundhog Day STEM Challenge: Exploring Shadows, Light & Weather Predictions with  Free STEM Worksheets

Before starting this challenge give kids an overview of what Groundhog Day is!

Groundhog Day is celebrated on February 2nd each year in the United States and Canada. It is a fun tradition where people observe a groundhog’s behavior to predict the weather for the next six weeks.

Why is it Celebrated?

The tradition comes from an old European belief that winter will last six more weeks if a hibernating animal sees its shadow on a sunny day. If it does not see its shadow (meaning the day is cloudy), spring will come early.

German immigrants brought this tradition to Pennsylvania, where it became Groundhog Day, with Punxsutawney Phil being the most famous groundhog.

How Does It Work?

• Every February 2nd in Punxsutawney, Pennsylvania, a groundhog named Punxsutawney Phil emerges from his burrow.
• If Phil sees his shadow, winter will continue for six more weeks.
• If he doesn’t see his shadow, spring will arrive early.
• It’s a fun and lighthearted event rather than a scientific weather prediction, but it has become a popular tradition with festivals, media coverage, and even a famous movie, Groundhog Day (1993).

I knew the classroom teachers in my school would be delving deep into Groundhog Day discussions, so I decided to take a slightly different approach: focus on shadows! We talked briefly about the tradition of Groundhog Day so the kids understood why we were doing the activity, but then we jumped straight into hands-on STEM learning. Flashlights, shadows, and creative exploration? 

Groundhog Day STEM Challenge

Lesson Plan Outline

Grade Level: K1 to K-5

NGSS Standards:

• K-2-ETS1-1 (Engineering Design)

• 1-PS4-3 (Light and Shadows)

• 3-5-ETS1-2 (Design Solutions)

Learning Objectives:

1. Understand how light angles affect shadow length.
2. Explore how weather impacts shadow visibility.
3. Apply the engineering design process to solve a problem.

Materials Needed

• Flashlights (as the "Sun")
• Printed groundhog cutouts (or student-drawn)
• Small objects (toy trees, buildings, rocks)
• Protractor (to measure light angles)
• White paper or poster board (for base)
• Rulers (to measure shadow length)
• Cotton balls/tissue paper (to simulate clouds)
• Pencils, markers, and worksheets (included below)

Shadow Science Engineers:

Investigate how light and shadow work by experimenting with a flashlight, objects, and angles.

1. Ask a Question

Goal: How can we predict if the groundhog will see its shadow?

Brainstorm with your team:

• What causes a shadow to appear?
• How does the sun’s position affect the size and direction of shadows?
• Why might clouds influence the groundhog’s ability to see its shadow?

2. Imagine Solutions

Challenge: Design a model to test how shadows change based on light angles and weather conditions.

Think about:

• How to position the flashlight to mimic the sun in the morning, noon, and during winter.
• How to create "clouds" using paper, cotton, or translucent materials to block or diffuse the light.

3. Plan & Design

Draw your team’s setup below:

• Label the flashlight as the "sun."
• Label the groundhog and any other objects used.
• Use arrows to show the direction of light.
• Add notes: 
• How will you adjust the flashlight to test different times of the day?
• How will you simulate cloudy weather?
• What observations will you record?

4. Create & Construct

Build your model using the materials provided.

Tips:

• Secure the groundhog by taping it to the base.
• Use a protractor to adjust the flashlight angle:
• 30° = Winter sun (low in the sky)
• 90° = Summer sun (directly overhead)
• Simulate cloudy weather by adding cotton balls or translucent paper to block light.

5. Experiment & Test

Data Table:

Time of Day (Flashlight Angle), Shadow Length (cm), Weather (Clear/Cloudy), Groundhog Sees Shadow? (Yes/No)

    Morning (Low angle)     Clear

    Noon (High angle)         Cloudy

6. Improve & Revise

• What worked? What didn’t?
• How could you make shadows clearer or test more weather conditions?
• Redesign your model and test again!

Engineering Design Process Integration

• Ask: Introduce Groundhog Day tradition and the science of shadows.
• Imagine: Show examples of sun angles (use a globe and flashlight demo).
• Plan: Teams sketch their ideas and justify material choices.
• Create: Build models while troubleshooting stability (e.g., flashlight stands).
• Experiment: Test hypotheses and record data.
• Improve: Reflect on failures (e.g., “Our shadow was too faint—let’s use brighter light!”).

Extension Activities

• Real-World Connection: Research how ancient cultures used shadows (e.g., sundials).
• Math Integration: Graph shadow lengths vs. light angles.
• Creative Writing: Write a story from the groundhog’s perspective: “The Day I Saw My Shadow…”

Teacher Tips

• Differentiation: Simplify for younger grades (focus on shadows/light) or add complexity (calculate angles) for older students.
• Safety: Remind students not to shine flashlights in their eyes.
• Vocabulary: Light source, shadow, angle, prediction, prototype.

Reflection & Assessment

• Exit Ticket: “Why do shadows change during the day? How does weather affect this?”
• Rubric: Teamwork, creativity, use of data, and redesign effort.

This lesson is intentionally designed to be adaptable for a wide range of elementary grades (Kindergarten to 5th grade). Here’s why:

1. Flexibility:

• Younger students (K-2) can focus on observing shadows and basic cause/effect (e.g., "If the light is low, the shadow is long!").
• Older students (3-5) can dive deeper into measuring angles, graphing data, and engineering design (e.g., "How does a 30° angle compare to a 90° angle?").

2. Differentiation: 

Teachers can simplify or extend activities based on their class’s needs.

• Example: Kindergartners might use trial-and-error to adjust flashlight angles, while 5th graders use protractors for precision.

Why These NGSS Standards?

The Next Generation Science Standards (NGSS) listed align with the lesson’s focus on light, shadows, and engineering design:

1. K-2-ETS1-1 (Engineering Design):

• Relevance: Students "ask questions, imagine solutions, and build models" (e.g., designing a shadow-prediction system).
• Activity: Drawing plans, testing prototypes, and revising models.

2. 1-PS4-3 (Light and Shadows):

• Relevance: First graders explore how light interacts with objects to form shadows.
• Activity: Testing how flashlight angles change shadow length.

3. 3-5-ETS1-2 (Design Solutions):

• Relevance: Older students "analyze data to refine solutions" (e.g., improving their shadow models based on test results).
• Activity: Using rulers to measure shadows and adjusting light angles for accuracy.

Key Takeaways

• K-5 allows the lesson to grow with students’ skills, from basic observation to critical analysis.
• NGSS Standards ensure the lesson meets science and engineering goals for different grade bands.

The Groundhog Day theme makes abstract concepts (light angles, engineering) tangible and fun!

Download Groundhog Day STEM Challenge worksheets from here

Groundhog Day STEM Challenges Cover Photo 

Groundhog Day STEM Challenges  Worksheets

Groundhog Cutout

This simple yet powerful STEM activity helps kids explore light, shadows, and weather science in a way that feels like play! By adjusting angles, adding "clouds," and testing predictions, they’re engaging in real-world problem-solving, fine motor work, and critical thinking—all while having fun. Plus, it’s a great way to tie in science, engineering, and math standards without extra prep!

Want to take it further? Use Google Chrome and Google Workspace to organize lesson plans, track student observations, and share digital STEM journals. If you haven’t already, download Google Chrome for a faster, more seamless experience, making it easier than ever to access free resources, worksheets, and interactive tools to keep kids learning.