Atmosphere Basics
What is the atmosphere?
The layer of gases surrounding Earth.
Which gas do humans need to breathe?
Oxygen.
What is the most abundant gas in Earth's atmosphere?
Nitrogen.
Which gas supports burning?
Oxygen.
What is the process by which liquid water changes into water vapour?
Evaporation.
What force holds the atmosphere around Earth?
Gravity.
Which gas do plants absorb during photosynthesis?
Carbon dioxide.
Approximately what percentage of dry air is oxygen?
21%.
Which gas do plants use to make food during photosynthesis?
Carbon dioxide.
What is the process by which water vapour changes into liquid water droplets?
Condensation.
Does the atmosphere have a sharp boundary where it ends?
No, it gradually becomes thinner and merges into space.
What substance in the atmosphere helps form clouds and rain?
Water vapour.
Approximately what percentage of dry air is nitrogen?
78%.
Which gas is important for making proteins and DNA after being converted into usable compounds?
Nitrogen.
Do plants use oxygen for cellular respiration?
Yes, plants use oxygen to release energy from food.
Why is the atmosphere compared to an invisible blanket?
It surrounds Earth, helps regulate temperature, and protects life.
What protects Earth from much of the Sun's harmful ultraviolet radiation?
The ozone layer.
Which gas makes up approximately 0.93% of dry air?
Argon.
Which greenhouse gas is released by wetlands, livestock, and fossil fuel production?
Methane.
Why can't most living organisms use nitrogen gas directly from the atmosphere?
Nitrogen must first be converted into usable compounds, often by bacteria.
What would happen if Earth had no atmosphere?
Most life on Earth could not survive because there would be no breathable air, very little protection from harmful radiation, and extreme temperature changes.
Name three ways the atmosphere supports life on Earth.
It provides oxygen, regulates temperature, and protects life from harmful UV radiation.
Why is water vapor not included in the percentages of dry air?
Because the amount of water vapour changes depending on location and weather conditions.
Why is carbon dioxide important even though it makes up only about 0.04% of dry air?
It helps trap heat in the atmosphere and is needed by plants for photosynthesis.
How is the air inside a balloon different from the atmosphere surrounding Earth?
A balloon's rubber holds air inside, while Earth's gravity holds most atmospheric gases near the planet.