What is the Kármán line?

A common boundary of space about 100 km up

The Earth's Atmosphere Quiz – Facts Worth Knowing

Take the Earth's atmosphere quiz to explore the gases in air, the troposphere, stratosphere, mesosphere, thermosphere and exosphere, the ozone layer, the Kármán line and why the sky is blue. Ten questions with facts worth knowing.

Start the Earth's Atmosphere Quiz

🎯 Daily Trivia Challenge • 🧠 10 Questions • ⏱️ 150 Seconds

Question 1 / 10 Time: 150s

Gas
Which gas makes up most of Earth's atmosphere?
Oxygen
About what percentage of air is oxygen?
Weather
In which layer does weather happen?
Ozone
Which layer contains the ozone layer?
Meteors
In which layer do most meteors burn up?
Auroras
In which layer do auroras and the ISS occur?
Space
What is the Kármán line?
Jets
In which layer do airliners often cruise to avoid weather?
Blue
Why is the sky blue?
Thin
Where is about half of the atmosphere's mass?

Explanations: answer key for all 10 questions

Q1: Which gas makes up most of Earth's atmosphere?
Answer: Nitrogen
Nitrogen is about 78%.
Q2: About what percentage of air is oxygen?
Answer: About 21%
Argon is about 0.9%.
Q3: In which layer does weather happen?
Answer: Troposphere
It is the lowest layer.
Q4: Which layer contains the ozone layer?
Answer: Stratosphere
Ozone absorbs ultraviolet light.
Q5: In which layer do most meteors burn up?
Answer: Mesosphere
It is the coldest layer.
Q6: In which layer do auroras and the ISS occur?
Answer: Thermosphere
Temperatures there can be very high.
Q7: What is the Kármán line?
Answer: A common boundary of space about 100 km up
It is named after Theodore von Kármán.
Q8: In which layer do airliners often cruise to avoid weather?
Answer: Lower stratosphere
Commercial jets fly around 10-12 km.
Q9: Why is the sky blue?
Answer: Air scatters blue light more
This is Rayleigh scattering.
Q10: Where is about half of the atmosphere's mass?
Answer: Below about 5.5 kilometers
Air thins rapidly with height.

The Earth'S Atmosphere Quiz – The Blanket Around Earth

Earth's atmosphere is a thin layer of gases held by gravity. It is mostly nitrogen and oxygen, with small amounts of argon, carbon dioxide and water vapor. It provides air to breathe, shields us from harmful radiation and keeps the planet warm.

The atmosphere has layers. The troposphere holds weather and most of the air, the stratosphere contains the ozone layer, meteors burn up in the mesosphere and auroras glow in the thermosphere. The exosphere fades into space.

Human activity is changing the atmosphere by adding greenhouse gases and pollutants. Protecting it, as the world did by banning ozone-destroying chemicals, is essential for climate and health.

What This Quiz Teaches

This quiz is for students learning about the atmosphere.

What air is made of
Where weather happens
Where the ozone layer is
What the Kármán line is
Why the sky is blue

Did You Know?

Mount Everest's summit has about a third of sea-level air pressure.
Noctilucent clouds form in the mesosphere.
The exosphere fades out thousands of kilometers above Earth.
Clouds hold huge amounts of water.
Carbon dioxide is about 0.04% of air.