Cati Falkenstein
Posts: 4
Joined: Tue Nov 06, 2007 6:16 pm

Breaking sound barriers

Postby Cati Falkenstein » Thu Nov 15, 2007 10:32 am

What conditions have to be present to be able to take pictures of someone breaking the sound barrier?
"Daisy" Cati

Craig_Bridge
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Joined: Mon Oct 16, 2006 11:47 am

Postby Craig_Bridge » Thu Nov 15, 2007 1:54 pm

What do you want to show in the picture? Showing motion in a still photograph is an interesting artistic challenge but I'm not sure how this relates to science. Please explain.
-Craig

Cati Falkenstein
Posts: 4
Joined: Tue Nov 06, 2007 6:16 pm

Postby Cati Falkenstein » Thu Nov 15, 2007 7:57 pm

I have to explain WHY and HOW it happens.
"Daisy" Cati

Craig_Bridge
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Joined: Mon Oct 16, 2006 11:47 am

Postby Craig_Bridge » Fri Nov 16, 2007 6:10 am

I have to explain WHY and HOW it happens.

In this case, a sequence of "diagrams" maybe worth several thousand words. What you need to depict is the sound wave front traveling ahead of the object making the sound and show how as the object speeds up, waves from different points in time get closer as the object reaches the speed they are traveling.

This sounds more like homework and not a science fair project. This site is about helping investigators do science fair projects and not helping with homework.
-Craig

Cati Falkenstein
Posts: 4
Joined: Tue Nov 06, 2007 6:16 pm

Sonic Boom

Postby Cati Falkenstein » Fri Nov 16, 2007 7:48 am

Sorry. I was thinking about doing it for a science fair project. I found a really cool picture and video on the internet with a jet making a "cloud" right as it was breaking the sound barrier.

I'm interested because my aunt had told me her dad (my great-grandfather) knew Chuck Yeager. He was one of the lead mechanics on the plane Yeager flew when he broke the sound barrier for the first time.

But I have to explain the "how, when, where, why...etc." for the project.

Thanks for your time.

Cati
"Daisy" Cati

Craig_Bridge
Former Expert
Posts: 1297
Joined: Mon Oct 16, 2006 11:47 am

Postby Craig_Bridge » Fri Nov 16, 2007 8:29 am

Try reading up on the scientific method and your question links on the Science Fair Project guide http://www.sciencebuddies.org/mentoring/project_guide_index.shtml

Demonstration projects like what you have described typically aren't the ones that are the top projects at science fairs.

I think I've seen high speed film of something similar to what you are refering to. I think it involved being at an optimal sun angle and using polarized filters to detect air pressure waves by light scattering in front of at the leading surfaces. Something that is very expensive to actually do.

A lot of lower cost high speed testing today is done with rupture plate tunnels. They aren't wind tunnels per se, more like two long sections of 10 to 12 inch diameter pipe end to end separated by a rupture plate. You create a high vaccum in the test area and beyond and pressurize the other end and then break the rupture plate to create a high velocity wave of air pressure traveling down the pipe. These setups and all of the high speed instrumentation are very expensive; however, they are much more repeatable than actually flying something.
-Craig


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