Long ago, a powerful leader named Kublai Khan tried to conquer Japan with his army. But just as they set sail, a huge storm called a typhoon hit, destroying their ships and saving Japan. When the Mongols tried again a few years later with an even bigger army, another typhoon appeared and stopped them once more. The Japanese believed these storms were sent by their emperor to protect them and called them “kamikaze,” which means “divine wind.”
In the Caribbean and Central America, ancient cultures like the Taíno and Maya told stories of a storm god named Huracán. They even created artifacts showing the spiral shapes of these storms, long before Western scientists figured it out in 1831. Today, we know these storms as hurricanes in the Atlantic, and they are some of the most powerful forces in nature.
Hurricanes are massive storms that can stretch over 100 miles wide and travel hundreds of miles. They have towering walls of clouds and ice. But how do they form? The basic ingredients are heat and wind. Wind moves from areas of high pressure to low pressure, creating the strong winds of a hurricane. But why do they spin?
The spinning of hurricanes is due to the Coriolis effect. If Earth didn’t spin, hurricanes wouldn’t either. Near the equator, winds move eastward because of Earth’s rotation. As these winds move toward the poles, they encounter slower-moving air, causing them to spin. This is why hurricanes spin counterclockwise in the northern hemisphere and clockwise in the southern hemisphere.
Heat from warm ocean water is crucial for hurricanes. A hurricane works like an engine, similar to a concept by French physicist Nicolas Carnot. As air moves toward the hurricane’s center, it should cool due to low pressure, but it stays warm because of water evaporation. This process releases heat, keeping the hurricane going.
A hurricane can carry over a hundred billion pounds of water! As water vapor rises and cools, it releases heat, making the top of the hurricane warmer. This heat is then radiated into space, and the air sinks back down, warming up again, ready to fuel the hurricane further. This cycle makes hurricanes incredibly powerful, using as much energy as the entire United States.
Hurricanes are categorized by wind speed, from Category 1 to Category 5. Scientists believe the maximum wind speed should be around 190 mph, but Typhoon Haiyan reached 195 mph in 2013. Some wonder if we need a Category 6, but after a certain point, all hurricanes cause similar destruction.
As Earth’s climate warms, hurricanes could become even more powerful. This is a reminder of the impact we have on our environment and why it’s important to take care of our planet.
Here’s something to think about: Jupiter has a giant storm called the Great Red Spot that spins counterclockwise, unlike southern hemisphere hurricanes on Earth. Why do you think that is? Keep exploring and learning!
Imagine you are a storyteller from ancient Japan or the Caribbean. Create a storyboard that illustrates the story of the kamikaze or the storm god Huracán. Use drawings and captions to show how these storms impacted the people and their beliefs. Share your storyboard with the class and explain the significance of these stories in ancient cultures.
Using simple materials like a plastic bottle, water, and food coloring, create a model to demonstrate how hurricanes form and spin. Observe the Coriolis effect by swirling the water and discuss how Earth’s rotation influences hurricane movement. Present your model to the class and explain the science behind hurricane formation.
Conduct research on a recent hurricane, such as Hurricane Katrina or Typhoon Haiyan. Create a presentation that includes the hurricane’s path, wind speeds, and the impact it had on affected areas. Discuss how the hurricane’s power compares to the energy usage of a country, and present your findings to the class.
Participate in a class debate on whether a Category 6 should be added to the hurricane scale. Research arguments for and against the idea, considering factors like wind speed and destruction levels. Present your arguments and listen to opposing views, then vote on the most convincing position.
In small groups, discuss how climate change might affect the frequency and intensity of hurricanes. Use data and predictions from scientific studies to support your discussion. Consider what actions can be taken to mitigate these effects and present your group’s ideas to the class.
Here’s a sanitized version of the provided YouTube transcript:
—
According to legend, when Kublai Khan’s army set sail to conquer Japan, a powerful typhoon, a Pacific tropical cyclone, arrived unexpectedly, destroying Khan’s fleet and saving Japan. When the Mongols returned a few years later with an even larger army, another typhoon appeared and turned the invading fleet into driftwood. Believing their emperor had summoned the storms to rescue them, the Japanese named these typhoons “divine wind,” or kamikaze.
Native cultures in the Caribbean and Central America, such as the Taíno and Maya, shared stories of Huracán, a god who brought wind and storms. Their ancient artifacts indicate they recognized the spiral shapes of these storms long before Western scientists did, who wouldn’t understand this until 1831. Tropical cyclones are known by different names in various oceans, but Atlantic hurricanes, like Katrina and Sandy, are among the most well-known. These storms are some of the most formidable challenges that nature presents.
A fully formed hurricane can span more than 100 miles and travel hundreds of miles, with walls of clouds and ice extending through the lower layers of our atmosphere. But how does such a massive storm form? The basic ingredients for a hurricane are quite simple: heat and wind. The wind is straightforward; wherever there is low air pressure, air moves in to fill that void, creating a hurricane’s powerful winds. However, this doesn’t explain why they spin.
A hurricane’s winds want to move in a straight line, but their path is deflected due to the Coriolis effect. If Earth weren’t spinning, hurricanes wouldn’t form. A 100 mph wind blowing north near the equator is also moving east, following Earth’s rotation. Because Earth is roughly spherical, the rotation slows as we approach the poles. As the wind moves north, the atmosphere and the Earth below it rotate more slowly, causing the wind’s eastward motion to outpace Earth’s rotation, pushing it eastward. The opposite occurs on the other side, where winds move slower and are pulled westward. This is why cyclones spin clockwise in the southern hemisphere and counterclockwise in the northern hemisphere.
Hurricanes cannot form too close to the equator because there isn’t enough difference in rotation at low latitudes to initiate spinning. As we move closer to the eye of the hurricane, wind speeds increase due to angular momentum, similar to how a figure skater spins faster when pulling their arms in. The second key ingredient is heat from warm water. A hurricane operates much like an engine, specifically an ideal engine conceptualized by French physicist Nicolas Carnot.
First, a piston rises. Normally, reducing pressure cools a gas, but in a Carnot Engine, heat is added so the temperature remains constant even as pressure drops. If we turn off the heat and continue to lower the pressure, the gas cools. Next, we reverse the first step by lowering the piston. We would expect this higher pressure to heat the gas, but in our engine, we have a mechanism to draw heat out, keeping the temperature constant. Finally, as we compress the piston while stopping heat removal, the temperature rises along with pressure.
Ideal engines like this don’t exist in reality, but a hurricane is one of the closest examples we have. As winds flow toward the center of a hurricane, we would expect the low pressure to cool them, but the air remains warm due to the massive amounts of water evaporating. An average hurricane can carry over a hundred billion pounds of water!
So how does evaporation keep the wind warm? Converting water from liquid to vapor requires energy, which is why you feel cool when you exit a pool or why soup cools when left out too long. Evaporating water takes heat with it, which is stored in the wind, maintaining the temperature even as pressure decreases, similar to the first step of our ideal engine. As the air rises, the heat source is lost, causing water vapor to condense back into liquid, releasing its stored heat into the atmosphere. The temperature is actually higher at the top of a hurricane due to the heat released by condensing water vapor.
High up, the air releases radiation into space as it flows out and down, mirroring the third step. Finally, that air sinks back to Earth, compressing and warming, readying the hurricane engine for another cycle. This feedback loop transforms hurricanes into self-sufficient engines of destruction. A typical tropical cyclone consumes the same amount of power as the entire United States. As long as there’s enough warm water, it continues to feed itself, growing larger and larger until…
Is there a limit to how powerful a hurricane can be? Size and rainfall are the biggest indicators of a storm’s severity, but hurricane intensity is rated by wind speed. Category 1 hurricanes are the weakest, while anything over 157 mph falls into Category 5. Using equations for Carnot’s ideal engine and data about Earth’s climate, scientists suggest that 190 mph should be the maximum theoretical wind speed. However, after Typhoon Haiyan reached 195 mph in 2013, does that mean it’s time to introduce a Category 6?
Let’s be realistic. After a certain wind speed, all destruction looks similar, so adding another category of “bad” doesn’t make much sense. But it does give us something to ponder. As Earth’s climate warms, we are adding more heat and fuel to these engines of destruction, which is another reason to reconsider our impact on the environment.
Stay curious! If you want a chance to win a stylish “It’s Okay To Be Smart” t-shirt, just email us your answer to this question: There’s a massive spinning storm in Jupiter’s southern hemisphere, known as the Great Red Spot. Jupiter spins in the same direction as Earth, but the Great Red Spot spins counterclockwise, the opposite direction of southern hemisphere hurricanes. Why is that? We’ll randomly select 5 correct responses to receive a t-shirt and will provide the answer in a future video.
—
This version maintains the informative content while removing any potentially sensitive or inappropriate language.
Typhoon – A typhoon is a mature tropical cyclone that develops in the western part of the North Pacific Ocean. – Typhoons can cause severe damage to coastal areas due to their strong winds and heavy rainfall.
Hurricanes – Hurricanes are large, swirling storms with strong winds and heavy rain that form over warm ocean waters in the Atlantic Ocean and eastern Pacific Ocean. – The hurricane season in the Atlantic typically runs from June to November.
Coriolis – The Coriolis effect is the apparent deflection of moving objects when viewed in a rotating reference frame, such as the rotation of the Earth affecting wind patterns. – The Coriolis effect causes winds to curve to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.
Heat – Heat is a form of energy that is transferred between systems or objects with different temperatures, flowing from the hotter to the cooler one. – When a metal rod is heated at one end, the heat travels to the cooler end through conduction.
Wind – Wind is the movement of air from an area of high pressure to an area of low pressure. – The wind picked up speed as the storm approached, bending the trees in its path.
Pressure – Pressure is the force exerted per unit area on the surface of an object, often measured in Pascals (Pa) in scientific contexts. – Atmospheric pressure decreases as altitude increases, which is why mountain climbers often carry oxygen tanks.
Climate – Climate refers to the long-term patterns and averages of temperature, humidity, wind, and precipitation in a particular region. – The climate of a desert is typically hot and dry, with very little rainfall throughout the year.
Storms – Storms are disturbances in the atmosphere characterized by strong winds, rain, thunder, lightning, or snow. – Thunderstorms can develop rapidly and are often accompanied by heavy rain and lightning.
