Welcome Back to The Climate Classroom!
Last time, we explored how hail forms when cold water droplets collide inside thunderstorms. Today, we’ll discover how thunderstorms hold chunks of ice in the air—and investigate how strong those updrafts need to be for different sizes of hail.
Materials Needed
- 2 ping pong balls
- 1 golf ball
- 1 hair dryer
- Large clear plastic or glass container
- 2 beakers or drinking glasses
- Red food dye
Experiment Part 1: Demonstrating Updrafts
- Prep the Tub:
Fill your clear container with cold water. Add ice to make it extra cold. - Prepare the Hot Water:
Pour hot (not boiling) water into one glass, add 10 drops of red food dye, and stir. - Observe:
Place the dyed hot water glass into the cold water tub. Watch the red water rise—this simulates an updraft!
(Why? Hot water is less dense, so it rises. The same happens with hot air in a thunderstorm.) - Repeat:
Now try with room temperature water. The red dye rises much slower—just like less dramatic temperature contrasts make weaker updrafts.
Experiment Part 2: Updraft Strength & Hail
Let’s simulate hailstones:
Place a ping pong ball over the hair dryer (lowest heat and fan).
- Observation: It hovers.
Try the heavier golf ball (same settings).
- Observation: It won’t rise.
Switch to the highest fan speed.
- Observation: The golf ball lifts!
Takeaway: Stronger updrafts can hold heavier hailstones in the air. Weaker updrafts can only keep lighter ones aloft.
Science Behind the Storms
Thunderstorms occur when warm, moist air rapidly rises into colder, drier air above.
The greater the contrast in temperature, the faster the air rises—and the stronger the updraft.
As hail forms, cold water freezes onto a piece of ice caught in the updraft. When the updraft can't hold the hailstone anymore, it falls to the ground.
Big temperature differences create stronger updrafts, leading to bigger hail.
Hail Sizes & Updraft Speeds
Meteorologists measure hail by diameter—using familiar objects for reference:
- Quarter-sized hail (1+ inch):
Needs updrafts near 50 miles per hour - Golf ball-sized hail:
About 65 mph - Baseball-sized hail:
About 81 mph - Softball-sized hail:
About 103 mph
Anything above an inch in diameter (quarter size+) is considered severe and can cause damage.
Closing Thoughts
It takes massive amounts of energy to create updrafts strong enough to keep large hailstones in the air. That’s what makes severe thunderstorms so powerful—and potentially dangerous.
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