Hey Y'all,
This is something I've come up against several times...most recently, on the weekends I'll be out back working the BBQ and while I'm letting the meat and fire do their thing, I'll take a couple of whips out there and do some cracking. It's gotten to where I'll get a small crowd of neighborhood kids on bikes pulling up to watch, and then they start asking questions, inevitably one of them is "What makes it make that noise?" These kids usually range from about 5-11 years old. I ask if they know what a sonic boom is, and I'm usually met with blank stares. Once my neice asked me and I just told her when something goes faster than sound, it makes a loud bang, and she seemed satisfied...then my Father in Law, who is a retired Navy chief that's worked on airplanes his whole life, tried to give her the very detailed explanation and she glazed over...I was wondering, how do any of you that have encountered this handle it?
How do you explain the sonic boom to little children?
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Tyler Blake
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How do you explain the sonic boom to little children?
Yaprimascharif, Yahasanna Hadisany, elafinas tabachu, Dari chalemy elasin!
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Jeremy McEachern
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Jeremy McEachern
You're referring to the doppler effect, and I don't think that has anything to do with a whip cracking. When the string breaks the sound barrier and the air suddenly rushes is what makes the noise, but the doppler effect is has to do with frequency of sound ( it's higher pitched when coming to you because the waves are closer together, while lower pitched when going away because the waves are further apart ). You probably know that I just wanted to be sure we were all talking about the same thing.
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Franco Zoccali
Here's one:
Air is a lot like water. When you touch water slowly you can move through it pretty easily right? But when you hit it hard, like when you get a belly flop in the pool, it feel hard and makes a big splash with water going all over the place and a lot of noise. Well air is a lot like that. If you move through air slowly, like when you're walking or even running, you can move through it pretty easy. But when you go really fast, it starts to get harder to move because the air is rubbing against whatever is going through it a lot more, because it's going very fast, like an airplane say. But, when you move through the air really really really fast, but you do it all of a sudden, the air does what water does when you get a belly flop; it makes like a big splash but because air is invisible, you can't see it really, but you can hear it and it sounds like a bang.
So a whip gets smaller the further out you get and because it's smaller it doesn't weight as much right, it's lighter, so it doesn't take as mush force to move and this makes it go fast. It's like if you push on something really heavy, like a big box full of rocks, you can move it but not really fast. Now if you push on something that's really light like a soccer ball with the same amount of strength as with the heavy box full of rocks, you can move it a lot faster because it doesn't weigh as much. So making a whip move is like moving something that gets lighter and lighter because it gets smaller and smaller. And when the little string at the end gets fast enough, it makes a belly flop through the air and it goes bang. If you just move the whip a little it will move but it won't go bang, it won't crack. But when you make it go really fast, the tip goes faster and faster and it cracks and makes all that noise. And sometimes, like when the air is very humid, like when there is fog or something, if you look closely, you can see the air make the belly flop; it looks like a puff of smoke appears out of thin air!
That's why a whip makes all that noise.
What do you think? Think a kid would get it? I do.
Franco
Air is a lot like water. When you touch water slowly you can move through it pretty easily right? But when you hit it hard, like when you get a belly flop in the pool, it feel hard and makes a big splash with water going all over the place and a lot of noise. Well air is a lot like that. If you move through air slowly, like when you're walking or even running, you can move through it pretty easy. But when you go really fast, it starts to get harder to move because the air is rubbing against whatever is going through it a lot more, because it's going very fast, like an airplane say. But, when you move through the air really really really fast, but you do it all of a sudden, the air does what water does when you get a belly flop; it makes like a big splash but because air is invisible, you can't see it really, but you can hear it and it sounds like a bang.
So a whip gets smaller the further out you get and because it's smaller it doesn't weight as much right, it's lighter, so it doesn't take as mush force to move and this makes it go fast. It's like if you push on something really heavy, like a big box full of rocks, you can move it but not really fast. Now if you push on something that's really light like a soccer ball with the same amount of strength as with the heavy box full of rocks, you can move it a lot faster because it doesn't weigh as much. So making a whip move is like moving something that gets lighter and lighter because it gets smaller and smaller. And when the little string at the end gets fast enough, it makes a belly flop through the air and it goes bang. If you just move the whip a little it will move but it won't go bang, it won't crack. But when you make it go really fast, the tip goes faster and faster and it cracks and makes all that noise. And sometimes, like when the air is very humid, like when there is fog or something, if you look closely, you can see the air make the belly flop; it looks like a puff of smoke appears out of thin air!
That's why a whip makes all that noise.
What do you think? Think a kid would get it? I do.
Franco
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Jeremy McEachern
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Robert Wurth
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Jeff Roseborough
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As my old 8th grade shop teacher said "KISS, Keep It Simple Stupid".
Ask the kids if they have ever seen a fighter jet fly overhead and make a loud "boom" as it goes by? A whip does the same thing.
For more advanced kids yes you could go into the air displacement explanation. You could even bring up thunder and lightning. Electricity travels so fast through the air it pushes air aside creating a pressure wave that we hear as thunder. A jet flying through the air at 600+ mph pushes air aside creating a pressure wave aka sonic boom.
Tailor the explanation to the audience.
Jeff
Ask the kids if they have ever seen a fighter jet fly overhead and make a loud "boom" as it goes by? A whip does the same thing.
For more advanced kids yes you could go into the air displacement explanation. You could even bring up thunder and lightning. Electricity travels so fast through the air it pushes air aside creating a pressure wave that we hear as thunder. A jet flying through the air at 600+ mph pushes air aside creating a pressure wave aka sonic boom.
Tailor the explanation to the audience.
Jeff
Here's wishing you find time for the things you want to do, and for the things you need to do.
We see ourselves in our children and hope for a better future.
We see ourselves in our children and hope for a better future.
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Jeff Roseborough
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- Joined: Fri 3. Jul 2009, 09:12
- Location: Reno, NV, USA
I like this explanation also!Zuiun wrote:For very little kids, I've always simplified it to this:
When the whip goes faster than the speed of sound, it's really going faster than the air can get out of the way. The "boom" is just the crash of all that air trying to move out of the way.
Here's wishing you find time for the things you want to do, and for the things you need to do.
We see ourselves in our children and hope for a better future.
We see ourselves in our children and hope for a better future.
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Franco Zoccali
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Fritz Ehlers
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Franco Zoccali
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Jeremy McEachern
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Franco Zoccali
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Jeremy McEachern
That question popped into my mind the other day and I came up with this. It's not based off of anything, just a complete theory.Fritzfactor wrote:So how fast wopuld you have to move through water to make an aquatic equivalent of the sonic boom?
We know sound travels much faster through water then it does through air, right? So maybe it would simple be that you would have to travel as fast the the sound is moving in that particular area ( because like with air, what's in the water and depth would affect how fast the sound was traveling ).
Any thoughts? That may not be the case because water is thicker than air so it may displace at a slower speed ( if there is the equivalent of a sonic boom in water ).
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jbc8bd
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quattro
The speed of sound in water (20°C) is about 1400m/s. You can show a sonic boom simply with a wave when you move your finger through water. When you move it too fast then the wave rolls over, so you have break the speed of an surface wave. You can also see the mach cone. With this example you can see some effects of other shapes of an cracker, or speeds. But it is only an simple example it´s not 100% accurate.
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David Cross
The simplest explanation I have ever come up with is that the whip acts in much the same way as thunder does. Just as lightning causes air to rapidly expand, then rush back in (creating thunder), the tip of the whip also pushes air so quickly that it creates a similar vaccuum. It usually takes some time to get these two points across, but it often works.
For emphasis, I bring my hands together when describing the effect of the air rushing in to fill the vaccuum. By symbolizing the air with my hands, I am able to demonstrate that this effect can and should produce a loud sound.
For emphasis, I bring my hands together when describing the effect of the air rushing in to fill the vaccuum. By symbolizing the air with my hands, I am able to demonstrate that this effect can and should produce a loud sound.