Temperature Lapse Rate
Lesson notes
Overview
Air cools by about 6.5 °C per kilometre in the troposphere. This topic is rated beginner and is number 63 of 98 in Earth & Space. Core ideas and first intuitions. No prior knowledge needed.
What you are seeing
The panel above shows a graph of the function. Each slider changes one parameter, so you can see exactly how the curve bends, shifts or stretches. The animation is drawn live from the model, so everything you see responds to the sliders. Press Space to pause, use Restart to replay from the start, and change the speed to slow down quick events.
In depth
In the troposphere the air gets colder with altitude at an average rate of about 6.5 °C per kilometre, because rising air expands as the pressure falls and cools. Dry air cools faster, at 9.8 °C/km, while moist air cools more slowly because condensation releases latent heat. If the actual lapse rate is steeper than the adiabatic one, the air is unstable and thunderstorms may develop. A temperature inversion, where it rises with height, traps pollution.
Reading the relationship
The expression "Γ ≈ 6.5 K/km" is a compact summary of the idea. It uses the symbols Γ, K, k, m; name what each one stands for before you start. Notice that it contains a ratio, so increasing the denominator makes the result smaller. Then use the sliders to see how changing one quantity changes the others.
A guided exploration
1. Set every slider to its middle value and note the shape of the curve. 2. Move one slider at a time and describe whether the curve shifts, stretches or turns. 3. Find the value where the behaviour changes sharply, then connect it to the formula.
Try this
Start by only moving one slider at a time. Say aloud what you expect, then check.
Common pitfalls
Earth and space systems work on very different scales of time and distance. Check which scale a number refers to before comparing it with another.
How it connects
It builds on “Atmospheric Pressure with Altitude”, the topic before it in Earth & Space. Once you are comfortable, continue with “Wind Speed and Pressure Gradient”.
Why it matters
Earth and space science helps us understand our planet, its climate and the wider universe.
Where you might use it
- Revising “Temperature Lapse Rate” before a class, exam or certification
- Forecasting weather and understanding climate records and their uncertainty
- Planning for earthquakes, floods and other natural hazards in cities
- Interpreting satellite images, space missions and the age of rocks and stars
Frequently asked questions
What is Temperature Lapse Rate?
Air cools by about 6.5 °C per kilometre in the troposphere. It is a beginner topic in Earth & Space.
How do I use the Temperature Lapse Rate simulation?
The panel at the top shows a graph of the function. Each slider changes one parameter, so you can see exactly how the curve bends, shifts or stretches. Move the sliders one at a time, then press Space to pause the animation and look closer.
What does the formula mean?
The expression Γ ≈ 6.5 K/km packs the idea into symbols. Name each symbol first, then change one quantity with the sliders and see which others respond.
Who is this topic for?
Core ideas and first intuitions. No prior knowledge needed. If the quiz feels hard, reread the lesson notes and try the previous topic first.
What should I learn before this?
Start with “Atmospheric Pressure with Altitude”, the previous topic in Earth & Space. Each topic in a subject builds on the ones before it.
How do I track my progress?
Press “Mark as learned” on this page. Progress is stored only in this browser and is never sent anywhere. The Browse page can show topics you have learned or still need to learn.