Chimney Falls: Why & Where? What's the Mystery of Gravity?

  • Thread starter Khaled332
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In summary, a chimney falls due to the forces applied to it by its construction. The base of the chimney may hop into the air during the fall due to the forces applied. This is due to the chimney breaking in half along its length and the tower segments being fairly rigid.
  • #1
Khaled332
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When a tall chimney falls, it usually breaks in two at some point along its length. Why doesn’t it fall in one piece? Where will the break occur? Will the chimney bend towards or away from the ground after the break? If the chimney does not break, something even stranger may occur: the base of the chimney may hop into the air during the fall. How can it do this seemingly against gravity?
 
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  • #2
The characteristics of a chimney falling will be very dependent on its construction. A solid concrete one can act way different than a brick one (I'm assuming you're talking about factory-sized ones, not house-sized).

I'm not sure what you mean about the "hop". Can you be more descriptive about a specific instance?
 
  • #3
I am talking about factory sized chimneys indeed, and I am wondering how BOTH solid concrete chimney and brick chimney would act when they fall. When the base of the chimney hops into the air during free fall I am thinking that wind resistance and gravitational accelration causing large internal stress result in the chimney breaking before it even makes an impact on the ground. Thanks
 
  • #4
Khaled332 said:
I am talking about factory sized chimneys indeed, and I am wondering how BOTH solid concrete chimney and brick chimney would act when they fall. When the base of the chimney hops into the air during free fall I am thinking that wind resistance and gravitational accelration causing large internal stress result in the chimney breaking before it even makes an impact on the ground. Thanks

I still have no idea what you are talking about on this "hop" thing.
 
  • #5
do you have some videos that show some examples?
 
  • #6
The 'hop' must be something to do with a (transverse) wave that is set up as the chimney hits the ground progressively along its length.
When comic actors fall over backwards, their feet always go up in the air, too.
 
  • #7
Khaled332 said:
When a tall chimney falls, it usually breaks in two at some point along its length. Why doesn’t it fall in one piece? Where will the break occur? Will the chimney bend towards or away from the ground after the break? If the chimney does not break, something even stranger may occur: the base of the chimney may hop into the air during the fall. How can it do this seemingly against gravity?
Chimneys are built to withstand great compressive forces along their length, but not that strong of the side-to-side forces. When it falls over, to move at constant angular velocity along its entire length, the end of the chimney must experience much greater acceleration than the middle, and the bottom is almost stationary. This puts the stress on the chimney as if the middle is being pulled down, while the top and bottom are being pulled up. So no wonder that the chimney snaps more often than not.

The hop part is trickier, I have a thought on this, but I'm going to need to write it up and see if what I think happens actually makes any sense.
 
  • #8
Ok, this took a while, so I hope it helps clear it up a little.

Keeping in mind that the chimney does break in half, let's model it as two rigid halves connected by a joint. The joint will be allowed to rotate freely to simulate breaking point. Keep in mind that this will greatly exaggerate the result. So the first image attached is an animation showing the simulated tower collapsing. Tendency to snap in half is absolutely clear. Second image is the plot of the force required to support the tower at the base. The initial spike is from the model settling in. From there, the force stays fairly level for a while, and then decreases as the tower leans and collapses. Finally, right before the tower crashes into the ground, something interesting happens. The force goes negative. That means that the bottom of the tower tries to "hop" into the air, and my constraint, requiring that the tower stays planted, is not letting it.

It's not perfectly clear to me why this happens. I suspect, the top half pressing down on the far end of the bottom half causes this, but I'm not sure how the top half ends up moving in such a way as to cause that. Either way, this is purely an outcome of tower segments being fairly rigid and interacting with each other.
 

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  • #9
Thank you so much K^2 your knowledge is much appreciated.
 

1. Why do objects fall down chimney falls instead of floating up?

Objects fall down chimney falls due to the force of gravity. Gravity is a fundamental force of nature that attracts objects with mass towards each other. The larger the mass of an object, the stronger its gravitational pull. In the case of chimney falls, the mass of the Earth is much greater than the mass of the objects falling, causing them to be pulled towards the Earth, rather than floating up.

2. What is the mystery behind gravity?

The mystery of gravity lies in its origin and mechanism. While scientists have a good understanding of how gravity works, they are still trying to understand its source and how it is transmitted between objects. Some theories suggest that gravity is caused by the curvature of space-time, while others propose the existence of a hypothetical particle called the graviton.

3. How is gravity related to the formation of chimney falls?

Gravity plays a crucial role in the formation of chimney falls. As water flows over the edge of a cliff, gravity pulls it down towards the Earth, causing erosion and the formation of a vertical channel. Over time, this channel deepens and widens, creating a chimney fall.

4. Why do some areas have more chimney falls than others?

The presence of chimney falls is determined by the geological and topographical features of a region. Areas with steep cliffs, large bodies of water, and a history of erosion are more likely to have chimney falls. Additionally, the local climate and weather patterns can also contribute to the formation of chimney falls.

5. Is there a way to predict where chimney falls will form?

While scientists can identify regions that are more prone to chimney falls, it is not possible to predict exactly where they will form. This is because the formation of chimney falls is a complex process that is influenced by many factors, such as water flow, erosion, and geological features. However, ongoing research and advancements in technology may one day allow for more accurate predictions of chimney fall formation.

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