Key Concepts
This is the energy of motion of particles.
What is kinetic energy?
This is the main source of energy that heats Earth’s surface.
What is the Sun?
Warm air is more or less dense than cool air?
Less dense
As altitude increases, temperature usually…
decreases
What must happen to water droplets for hail to form?
They must freeze
This is the amount of matter in a given space.
What is density?
This is what happens to the air near the ground when the Sun heats the surface.
What is warming up (it warms up/gets warmer)?
What happens to less dense air?
It rises
If temperature decreases, what happens to particle motion?
Particles move slower
Where in a storm cloud does hail usually form?
High in the cloud
What happens to particle motion when temperature increases?
Particles move faster
A measure of the average kinetic energy—the energy of motion—of the particles (atoms or molecules) in a substance
What is temperature?
Why does warm air rise?
Particles move faster, spread out, making it less dense
At higher altitudes, water droplets are more likely to…
Freeze
Why are hailstorms more likely on hot days?
Warm air rises more strongly
Why does increasing temperature cause air to become less dense?
Particles move faster and spread farther apart
Why do surfaces like pavement get hotter than grass?
They absorb more solar energy (energy from the Sun).
What causes air to move in the atmosphere?
Differences in density caused by temperature differences
A storm cloud is 90°F at the bottom and 30°F at the top. What will likely happen to water droplets as they rise?
They will freeze into ice
What happens to rising air as it moves higher in the atmosphere?
It cools
A student says, “Warm air rises because it is lighter.”
What is missing from this explanation?
Explanation of particle motion and density (why it is less dense)
Explain how energy from the Sun leads to air movement.
Sun heats ground → air warms → particles move faster → air becomes less dense → air rises
Describe the full chain from temperature to air movement.
Temperature increases → particles move faster → spread apart → density decreases → air rises
A student observes that temperature decreases as altitude increases. How can this data help explain hail formation?
Rising air cools, causing water droplets to freeze into hail
Explain the full process of how a hailstorm forms on a hot, sunny day.
Sun heats ground → air warms → air rises → temperature decreases with altitude → water droplets freeze → hail forms