Use these easy, low-prep 100th Day STEM activities to help your students celebrate the 100th day of school with hands-on learning and lots of excitement.
100th Day STEM Activities For Kids
The 100th day of school is basically a teacher’s version of a mini-holiday; the kids show up buzzing with excitement, and it’s one of those days where everything feels a little extra fun. It’s the perfect chance to look back on the growth students have made while also sneaking in some hands-on math and engineering.
If you’re searching for 100th Day STEM ideas that are low-prep, meaningful, and won’t drain your teacher energy, you’re in the right place.
Below, you’ll find fun and easy 100th day of school activities you can add to your centers, rotations, or whole-group time without overthinking it. These pair perfectly with your 100th Day Fun Pack and help your day run smoothly with plenty of learning packed into the celebration.
Table of Contents
- 100th Day STEM Activities For Kids
- What is the 100th Day of School?
- What is STEM?
- 12 Educational 100th Day Activities
- Additional 100th Day STEM Ideas
- 100th Day of School Resources
- More 100th Day Activities
What is the 100th Day of School?
The 100th Day of School is a big classroom milestone that celebrates 100 days of learning, growth, and routines finally clicking into place. Teachers often turn it into a fun-filled day packed with activities focused on the number 100, like counting, building, writing, and simple STEM challenges. It’s a great way to sneak in math and problem-solving while still keeping things exciting for students.
What is STEM?
STEM stands for Science, Technology, Engineering, and Math, but it’s really all about helping kids learn how to think and solve problems. Instead of sitting and memorizing facts, students get to build, test, explore, and figure things out through hands-on activities.
They might design something, experiment with ideas, use technology, or apply math in ways that actually make sense. STEM encourages curiosity, teamwork, and creativity, and it gives students plenty of chances to learn from mistakes, which is often where the best learning happens.
12 Educational 100th Day Activities
These challenges are low-prep, engaging, and packed with learning but still easy enough to fit into a busy schedule. These activities will keep your students excited, focused, and proudly showing off their “100” creations all day long.
1. 100-Cup Building Challenge
There’s something magical about giving kids a huge stack of cups and saying, “Go build.” This challenge is perfect if you want an activity that gets kids moving and collaborating without needing more than a stack of cups and some floor space.
Materials:
- 100 plastic cups
- Floor or table space
- Optional: timer
How it works:
- Give groups 100 cups.
- Challenge them to build the tallest or most creative structure.
- Allow plenty of time for building, collapsing, and rebuilding.
- End with a gallery walk.
Teacher Tips:
- Use vocabulary like base and balance.
- Model stability testing.
- Encourage planning first.
2. 100th Day Fruit Loop Collections (Counting + STEM)
If students need something hands-on but a bit calmer, this cereal counting activity is perfect. It gives kids a concrete way to understand grouping to 100, and they love seeing their work slowly fill up the mat.
Materials:
- Fruit Loops or similar cereal
- Collection mats
- Glue
- Small bowls
How it works:
- Students make groups of 10 cereal pieces.
- Glue each group to a circle.
- After 10 groups, they reach 100.
- Extend with patterns or graphs.
Teacher Tips:
- A great math + STEM rotation.
- Discuss why grouping helps.
- Add a prediction question.
3. 100th Day STEM Task Cards
If you love giving students choice, these STEM task cards are perfect. Each card feels like a mini-challenge that sparks creativity, and students love picking the one that fits their personality.
Materials:
- 100th Day STEM cards
- Various building materials
- Recording sheets
How it works:
- Students choose a card.
- Gather 100 of the needed material.
- Plan, build, and revise.
- Record their process.
Teacher Tips:
- Great for center rotations.
- Encourage students to explain their designs.
- Try a reflection walk afterward.
4. Build With 100 Popsicle Sticks
Popsicle sticks are one of those supplies that always feel simple but end up producing the coolest creations. This activity is great if you want something structured but still open-ended. Students love the challenge of making something meaningful using exactly 100 sticks.
Materials:
- 100 sticks per group
- Markers
- Recording sheets
How it works:
- Students brainstorm and sketch.
- Build with their 100 sticks.
- Test and adjust.
- Draw and label the final version.
Teacher Tips:
- Perfect for teaching revision.
- Works well for morning STEM tubs.
5. Build the Number 100 With LEGO Bricks
Any time you pull out LEGO bricks, engagement skyrockets. This activity is great for connecting creativity with number sense because kids have to think about how to design a clear and recognizable “100.” It’s simple, it’s fun, and it gives students multiple ways to show understanding.
Materials:
- 100+ LEGO bricks
- Challenge cards
- Recording sheets
How it works:
- Students plan how to build “100.”
- Use exactly or at least 100 bricks.
- Add decorations or patterns.
Teacher Tips:
- Works great for partners.
- Try multiple design versions.
6. Snap Cube Tower Challenge
If your students love comparing heights, shapes, and colors, this snap cube activity will be a hit. Kids also love the challenge of making something impressive with exactly 100 cubes.
Materials:
- 100 snap cubes
- Challenge card
- Recording sheet
How it works:
- Kids plan their tower or shape.
- Build using 100 cubes.
- Compare heights and features.
Teacher Tips:
- Great way to add measurement.
- Have students estimate height first.
7. Marshmallow & Toothpick 100 Challenge
This is the perfect mix of engineering and excitement. Students love the idea of building with marshmallows, and it gets them thinking about structure, shape, and strength.
Materials:
- 100 mini marshmallows
- Toothpicks
- Recording sheets
How it works:
- Students plan a 3D structure.
- Build using toothpicks as connectors.
- Test and redesign.
Teacher Tips:
- Introduce terms like vertices and edges.
- Pair with a winter building-themed book.
Additional 100th Day STEM Ideas
8. 100-Link Paper Chain Challenge: A great whole-class or partner challenge that lets students visually see how “100” really adds up.
9. 100-Step Scavenger Hunt: Kids follow clues and walk exactly 100 steps to different stations, great for movement.
10. 100-Penny Structures: Students explore weight, balance, and design using just pennies.
11. 100-Piece Nature Collection: Collect 100 outdoor items and arrange them into a picture or map.
12. 100-Dot STEM Art: Create art with 100 dots and explain the grouping strategy.
13. 100th Day Hat Craft: Allow kids to create their own 100th Day hat to wear around school!
Celebrating the 100th day of school doesn’t have to be stressful or overcomplicated. With a few fun 100th Day STEM challenges and hands-on activities, your students can explore, create, and celebrate their learning in meaningful ways.
100th Day of School Resources
Free 100th Day Activity Hat
Want to add even more fun to your celebration? Don’t forget to grab the FREE 100th Day of School Hat! It’s the perfect low-prep extra that students love wearing during all your STEM challenges and activities. Click the image below to grab a copy.
100 Days STEM Activities
Try the 100th Day STEM Activities by Proud to be Primary. It includes everything you need: STEM challenge cards, recording sheets, and hands-on activity templates. It takes the prep work out so you can focus on making the day memorable, meaningful, and full of joy.
If you like this resource, you’ll love my 100th Day of School FUN PACK & 100th Day of School Fun Book!
More 100th Day Activities
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