Lesson 3 - Temperature and Humidity Sensor: Temperature Monitor to Track Composting phase
1. Engage: Why Does Compost Get Hot?
Observe the picture below:
Key Question
Why does compost get warm?
When billions of tiny microbes break down carbon-rich scraps in compost (like dead leaves or banana peels), they release heat as they grow and multiply. This heat builds up, making the pile warm—sometimes even as hot as 65℃!
2. Explore: Effects of Temperature on Composting
Good temperature management can tell composters how fast material is decomposing, when compost is ready, and whether there are any problems.
Temperature is a compost super indicator:
Fast decomposition: Warm piles (30–60℃) mean microbes are super active, turning waste into plant food quickly.
Ready compost: When temps drop below 20℃, microbes are done eating—your compost is ready to feed gardens!
Problem signs: Too hot (over 70℃) kills beneficial microbes; too cold means the pile is too dry, small, or lacks nutrients.
Moisture is just as vital: Microbes need water to digest food, like we need water to swallow! Too little moisture, and microbes slow down; too much, and the pile gets slimy (no oxygen can reach the microbes).
Key Question
How do we check temperature and moisture during the composting process?
Reveal: Today, we’ll use the micro:bit and sensors to track compost temperature, monitor and manage our composting process.
Meet the Temperature & Humidity Sensor: Measures how hot or cold the compost is, and checks how much water is in the compost pile.
3. Engineer: Build Your Compost Monitor
Let’s set up our sensors to display real-time temperature on the micro:bit:
Hardware connections:
Coding Steps:
1.Open MakeCode for micro:bit.
2.Create a new project.
3.Go to Extensions → enter boson → add the extension.
4.Drag these blocks into your code:
5.Download the code to your micro:bit. Now you’ll see temperature on the micro:bit screen!
4.Experience & Challenge: Test & Track Your Monitor
Activity 1
Make hardware connection and write a program to display temperature.
Record the classroom’s baseline temperature.
Activity 2
Modify the program to display the temperature value every 5 seconds.
Place the Temperature & Humidity Sensor and a cup of hot water inside a sealed clear box.
Observe the micro:bit: What happens to the numbers?
Record the numbers in the table every 5 seconds.
Guide students to observe that the temperature is rising(Temperature rises as warm air fills the box!)
Research: Look up how compost temperature evolves over time (hint: it rises to high levels, then cools down when decomposition is done).
Key Question
How can we view the temperature curve to help us determine the progress of composting?
Activity 3
Create a program that allows us to view the real-time curve of temperature changes.
Go to Show data Device to see the temperature changes.
5. Elaborate: Sensors for Land Conservation Beyond Compost
Temperature sensors are superheroes for protecting our planet’s land ecosystems:
Plant Growth: Track soil moisture to ensure garden or reforestation trees get just the right amount of water (no wasted water from overwatering!).
Wetland Protection: Monitor wetland humidity to preserve these critical habitats—they filter water and provide homes for frogs, birds, and insects.
Desert Restoration: Check soil moisture when planting drought-resistant plants, helping them survive and restore dry landscapes.
This work supports SDG 15: Life on Land—using tech to protect and restore our planet’s precious land ecosystems.
Key Takeaway: With simple sensors and code, we can be compost scientists and planet protectors, one data point at a time!
Lesson3.zip 
