How hot is the soil vs the air?

 

How hot is the soil vs the air? Time to take the @pascoscientific wireless temperature sensors for a summer stroll. 

🌱 Taking Science Outside – Using PASCO Wireless Temp Sensors in the Garden

When the classroom empties out for summer, the learning doesn’t have to stop — especially when you’ve got a garden, a question, and a set of PASCO wireless temperature sensors.

This week, we’re asking a deceptively simple question:

How hot is the soil compared to the air?
And more importantly: why?

Armed with our wireless temperature sensors, a bit of curiosity, and a sunny afternoon, we set out to explore what’s really going on under your feet and around your flowers.

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🌡️ The Tools: PASCO Wireless Temperature Sensors

We used PASCO’s wireless temp sensors because:

• They're robust and waterproof

• They record and transmit data directly to a phone, tablet, or laptop

• They log data over time — perfect for tracking changes during the day

• And crucially, they're fun and quick to use outdoors

With these, we can easily measure:

• Ambient air temperature

• Soil surface temperature

• Sub-surface (5cm or 10cm deep) soil temperatures

• Shaded vs sunny areas

• Temperature changes throughout the day

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🧪 The Experiment Setup

Location: My garden – part shaded by trees, part in direct sun.
Time: 10am to 6pm
Sensors:

• One sensor suspended 1 metre above the soil (air temp)

• One sensor placed on the surface of bare soil

• One sensor buried 10cm deep

• One additional pair in shaded areas for comparison

Data was logged every minute.

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📊 The Results: Surprising Differences

By early afternoon, we found:

Sensor Location	Temp (°C)
Air (1m above ground)	27.4°C
Soil Surface (in sun)	38.9°C
Soil Surface (in shade)	25.2°C
Soil @ 10cm deep	23.1°C

Key observations:

• Soil heats up significantly more than the air above it when in full sun.

• Shaded soil stays much cooler.

• Sub-surface soil temperatures are far more stable — barely changing across the day.

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🌤️ Why Does Soil Get Hotter Than Air?

Soil and air heat up in different ways:

• Air warms gradually as the sun heats the ground, which then radiates heat into the air.

• Soil absorbs the sun’s energy directly — especially if it's dark and dry — making it much hotter at the surface.

It’s all about:

• Thermal conductivity

• Surface albedo (how much sunlight is reflected vs absorbed)

• Moisture content (wet soil heats more slowly)

• Insulation (soil below the surface is protected from solar radiation)

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🌡️ Why This Experiment Matters

This simple garden investigation:

• Demonstrates how heat transfers and how materials absorb energy

• Reinforces ideas around specific heat capacity, energy flow, and climate science

• Is relevant to real-world issues like urban heat islands, green roof design, and agriculture

• Provides perfect data sets for GCSE and A-Level Science and Maths analysis

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🧠 Get Students to Investigate Themselves

Great questions to ask:

• How does soil temperature vary between grass, gravel, and concrete?

• What happens if you water the soil before testing?

• What’s the temperature difference between topsoil and compost?

• Can you model how long it takes for different materials to cool?

Extension for Physics/Maths:
Plot cooling curves or create linear/regression models from the data.

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🧪 Teaching Science Year-Round – Even in the Garden

At Philip M Russell Ltd, we use PASCO scientific sensors throughout the year. Whether in the classroom or outdoors, they help students see science in action, collect real data, and develop critical thinking.

Whether you’re learning about thermodynamics, climate change, or just curious about why your cat prefers the shaded soil — this is science you can do anywhere.

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🌿 Want to learn more with us?
We offer 1:1 Science tuition (GCSE & A-Level), and all lessons include hands-on investigation and data analysis — even online via our film studio.

📅 Now enrolling for September
🔗 www.philipmrussell.co.uk