5HW Flying Cows - assignment PDF

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Flying Cows Disasters: Geology vs. Hollywood

Introduction In the movie Twister (1996), meteorologists/storm chasers are in pursuit of a storm with which they can use to study the mechanics of a tornado. There are storm chasers in real life, and they will put themselves into harm's way just to get close enough to dangerous storms. In this scene, as the meteorologists are chasing a tornado, they see some pretty amazing things flying through the air around the tornado.

Learning Objectives ● Construct the plausibility of a tornado being able to lift a cow with wind. (4, 5, b, c) ● Relate how we should prepare for tornadoes vs. preparation for hurricanes. (2, 5, d)

Part 1: Watch the clip As you can see in the clip, the chasers are driving between tornadoes when they see that cows are also caught up in the tornado. 1. Without knowing the wind speed or magnitude of the storm, do you think it’s plausible that a tornado can pick up a cow? Yes, I believe its plausible that a cow could be picked up in a tornado. The movie definitely exaggerated because the cow just went flying. I don’t think it would happen like that in real life.

2. Again, without knowing wind speed, do you think a tornado would be able to pick up and transport a cow? I believe a tornado would be able to pick up a cow and move it a few feet at most. I don’t believe a tornado can pick up a cow and make it fly away. We have never experienced enough wind to make it rain cows, if so we would all be in trouble.

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Part 2: A look at the numbers When the force of drag equals the force of gravity, you fall at a constant rate, called the “terminal velocity.” This is approximately 120 mph for a person. This also implies the reverse, that a wind of 120 mph could pick a person up. So what does this have to do with our cow? To lift the cow, the pressure of the wind on the cow has to be at least equal to the weight of the cow divided by the area the cow presents to the wind.

Pressure Needed = Cow Weight / Available Cow Area From this, we can figure out the needed wind speed, using a known relationship between wind speed and pressure.

Important information Average Cow Height

3 ft

Average Cow Butt Height

3 ft

Average Cow Length

5 ft

Average Cow Butt Length

3 ft

Average Cow Weight

1200 lbs

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Questions 1. What is the area the cow presents to the wind? Cow Length x Cow Height = Cow Area Your Answer: ____15____ ft2 2. What is the pressure needed to lift the cow under these conditions? Cow Weight / Cow Area = Pressure Needed Your Answer: _____80____lbs/ft2 3. Use the “Force of Wind” chart from page 2. What wind speed is necessary to generate that much pressure? 175 mph 4. With this wind speed, what classification would this tornado be?

It would classify as an EF-4 tornado Okay, so it’s possible. But let’s be more realistic. The cow isn’t going to just stand there as the tornado approaches! It’s probably going to try to run away. This changes things… 5. What is the area the cow presents to the wind? Cow Butt Length x Cow Butt Height = Cow Butt Area Your Answer: ___9____ ft2 6. What is the pressure needed to lift the cow under these conditions? Cow Weight / Cow Butt Area = Pressure Needed Your Answer: ____133____lbs/ft2 7. Use the “Force of Wind” chart from page 2. What wind speed is necessary to generate that much pressure? 225 mph wind

8. With this wind speed, what classification would this tornado be? It would classify as an EF-5 tornado Thought Questions: 1. Based on your results, is it possible for a tornado to make a cow fly? Explain your answer. Yes, it is very possible. A tornado is not going to make it rain cows but some tornados do have

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enough wind to pick up a cow and could possibly move them.

2. Do you think the scene in “Twister” was realistic? Explain your reasoning. I believe it was realistic enough because of how high the wind speeds were. The only problem I have with the film is that they exaggerated the cows flying in the movie. That was the only unrealistic thing I had a problem with.

3. Without doing the math, if you calculated the area of your own body, what tornado classification do you think would be necessary to pick you up? I’m 6 foot and weigh about 200 pounds. I would have to say an EF-2 tornado could very easily pick me up. 100 mph winds would definitely get me up in the air if I jumped. 4. What do you think you should do in the event of a tornado (regardless of the storm's magnitude)? Explain your answer. If a tornado was coming to my house I would first go downstairs and find the best covering. I would make sure nothing could fall over and hit me and I would also brace myself for any random flying objects....