🚀 Your Challenge:
Can you build a LEGO robot that acts like a real flower?
Your robot should spin slowly to look for light, then stop when it finds the sun (or anything yellow)!
🌱 What Do Real Flowers Do?
Have you ever noticed how sunflowers turn to face the sun? That’s not just for fun—it’s a real plant behavior called phototropism.
🌞 Phototropism means:
Plants grow or move in response to light.
- 🌻 Sunflowers face east in the morning and follow the sun during the day.
- 🌿 The top of the plant grows faster on the shady side, which makes it bend toward light.
- 💡 Plants need light to make food through a process called photosynthesis.
💬 Fun Fact:
Some flowers stop turning once they’re grown, but younger ones still move every day!
🔧 Robot Build Instructions
You’ll build a flower that:
- Spins using a motor
- Looks like a flower using bricks and petals
- Stops when the color sensor sees yellow or a bright light
🛠️ Step 1: Build the Spinning Base
Build a sturdy base and mount a motor horizontally so it can spin a platform.
Make sure the whole thing doesn’t tip over when spinning!
We used the Twirling Teacups lesson as an introduction to a spinning base.

🪴 Step 2: Make the Stem
Use LEGO beams to make a vertical stem that connects your flower head to the spinning platform.

🌸 Step 3: Create the Flower
Your color sensor becomes the center of the flower.
Decorate it with bright petals—but make sure it can still “see” colors in front of it!

💻 Coding the Robot
Use this basic idea for your code:
forever:
Spin slowly
If color sensor sees yellow or a bright light:
Stop spinning
📹 Watch the example video for how this works:
Watch on YouTube
💡 Tip: You can use "wait until color sensor sees yellow" in your program, or detect brightness using the reflected light sensor mode.

🧪 Test Your Robot
Try these tests:
- Shine a flashlight near the sensor. Does it stop?
- Place a yellow object in front of it. Does it freeze?
- Does it keep spinning if there’s no light or yellow?
- Can you make it spin again after it stops?
🎨 Bonus Challenges
- Decorate your flower with more petals, leaves, or a bug friend!
- Make it change colors using lights when it stops.
- Build a garden of robots and see how they all behave together!
📓 Record Your Learning
Use these questions in your science notebook:
Question | Your Answer |
---|---|
What is phototropism? | |
How does your robot behave like a real flower? | |
What does the sensor do in your robot? | |
What did you change during testing? | |
What would you do differently next time? |
🌼 Share Your Build!
Take a photo or video of your robot in action and share it with your class or post with permission!