Tornadoes

We can define a tornado as a violent, rotating column of air usually extending from a severe thunderstorm to contact Earth’s surface on either land or water.

Now you generally think of a tornado as being on land; but you see, in this case, it can be on water. Now if the tornado is on water, you’re probably not going to notice it.

Mini-test: TORNADOES 

Question 1: Generally, a tornado is a rotating column of air connecting the ground to a
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Question 2: The area of the United States where tornadoes are most frequent is called
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The transcript is provided for your convenience
And it’s not going to inflict near as much damage as if it was on land. But nevertheless, a tornado can be on land or water. In fact, tornadoes can occur almost anywhere in the world except for Antarctica. But the most common and dangerous ones in the United States are between the Appalachian Mountains in the East, and the Rocky Mountains in the West, in an area called Tornado Alley. The states of Kansas and Oklahoma are both in the Tornado Alley, which is known for having lots of tornadoes. Now, the rotating column of air is invisible until a funnel forms from the condensed water droplets, or dust and debris from the ground, or maybe even a combination of the two. A tornado in itself is invisible because it’s just a rotating column of air, but that rotating column of air is going to pick up debris and water droplets; and that’s how it becomes visible.

Now the extreme rotating wind speeds reduce pressure inside of the funnel significantly. Now, because of the low pressure inside the funnel, the air molecules can expand because there is not as much pressure on them; but when air molecules expand, they have to perform more work to expand. So when they’re performing work, they’re using kinetic energy. And a type of energy is heat. So they’re releasing this energy which causes a release of heat, which causes the temperature to drop. And so the temperature drops until water vapor condenses into visible droplets.

Now we have a scale to measure the strength of a tornado. Of course, we can just look at the wind speed; but we have a scale called the Fujita Scale, or we can call it the F-Scale, which is a way to measure the intensity of a tornado on a scale of zero to five. So if you ask how big a tornado was, instead of giving a wind speed, you’re just given a number from zero to five. This does make it easier just to give you a general idea of how big a tornado was. And so, starting at a zero tornado, the wind has a speed of 40 to 72 miles per hour. And so, those types of tornadoes don’t cause a lot of damage. But some very violent F5 tornadoes can have wind speeds exceeding 310 miles an hour. And that can inflict some serious damage and loss of life. So that’s a look at tornadoes.

Next Lesson: Earth’s Structure