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Where can I get a conic section of wood slices?
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Aardvarks
Aug 20, 2016, 1:47:36 PM8/20/16
to
I am trying to help a math teacher spruce up a barren basement classroom
that currently looks like a prison cell.
I gave her an 18-inch WiFi antenna for her to put posters on saying it's a
parabola and showing the focal point.
But I want to find a conic section that shows that when you slice a conic,
you get circles, elipses, and hyperbolas.
https://www.andrews.edu/~calkins/math/webtexts/conicsl.jpg
If I were a great woodworker, I would just make one.
But I'm not that good and I don't have a lathe.
All I have is a circular chop saw.
Do you know of an easy way to make or buy conic sections (wood or plastic)?
https://www.andrews.edu/~calkins/math/webtexts/numb19.htm
that currently looks like a prison cell.
I gave her an 18-inch WiFi antenna for her to put posters on saying it's a
parabola and showing the focal point.
But I want to find a conic section that shows that when you slice a conic,
you get circles, elipses, and hyperbolas.
https://www.andrews.edu/~calkins/math/webtexts/conicsl.jpg
If I were a great woodworker, I would just make one.
But I'm not that good and I don't have a lathe.
All I have is a circular chop saw.
Do you know of an easy way to make or buy conic sections (wood or plastic)?
https://www.andrews.edu/~calkins/math/webtexts/numb19.htm
Retired
Aug 20, 2016, 1:54:15 PM8/20/16
to
dpb
Aug 20, 2016, 1:55:48 PM8/20/16
to
On 08/20/2016 12:47 PM, Aardvarks wrote:
...
> But I want to find a conic section that shows that when you slice a conic,
> you get circles, elipses, and hyperbolas.
...
Somebody (actually, I gargled and found quite a number) has already beat
you to it...
<http://www.eaieducation.com/Product/532031/Dissectible_Conic_Section_Model.aspx>
Now, what they're asking for them may not fit the budget...
--
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...
> But I want to find a conic section that shows that when you slice a conic,
> you get circles, elipses, and hyperbolas.
Somebody (actually, I gargled and found quite a number) has already beat
you to it...
<http://www.eaieducation.com/Product/532031/Dissectible_Conic_Section_Model.aspx>
Now, what they're asking for them may not fit the budget...
--
---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus
burfordTjustice
Aug 20, 2016, 1:58:28 PM8/20/16
to
Keith Nuttle
Aug 20, 2016, 2:12:57 PM8/20/16
to
If it would be me I would go down to Lowes and buy a piece of round wood
stock and just cut it at different angles to show how a round circle can
be come can become the other pieces.
If you can not find a piece of round wood, you could do the same thing
with a piece of PVC pipe. After cutting you could sand the rough edges
and actually use the Pipe as a stamp; ink it and print the circles, ,
elipses, and hyperbolas.
Doug Miller
Aug 20, 2016, 5:06:47 PM8/20/16
to
Keith Nuttle <Keith_...@sbcglobal.net> wrote in news:npa6j6$10p2$1...@gioia.aioe.org:
> On 08/20/2016 1:47 PM, Aardvarks wrote:
>> I am trying to help a math teacher spruce up a barren basement classroom
>> that currently looks like a prison cell.
>>
>> I gave her an 18-inch WiFi antenna for her to put posters on saying it's a
>> parabola and showing the focal point.
>>
>> But I want to find a conic section that shows that when you slice a conic,
>> you get circles, elipses, and hyperbolas.
>> https://www.andrews.edu/~calkins/math/webtexts/conicsl.jpg
>>
>> If I were a great woodworker, I would just make one.
>> But I'm not that good and I don't have a lathe.
>> All I have is a circular chop saw.
>>
>> Do you know of an easy way to make or buy conic sections (wood or plastic)?
>> https://www.andrews.edu/~calkins/math/webtexts/numb19.htm
>>
> You are half way there with the chop saw.
>
> If it would be me I would go down to Lowes and buy a piece of round wood
> stock and just cut it at different angles to show how a round circle can
> be come can become the other pieces.
It can't. If you cut a cylinder perpendicular to its axis, you get a circle. If you cut a cylinder at
any other angle, you get an ellipse. It is impossible to make a single cut through a cylinder
and get either a hyperbola or a parabola.
> On 08/20/2016 1:47 PM, Aardvarks wrote:
>> I am trying to help a math teacher spruce up a barren basement classroom
>> that currently looks like a prison cell.
>>
>> I gave her an 18-inch WiFi antenna for her to put posters on saying it's a
>> parabola and showing the focal point.
>>
>> But I want to find a conic section that shows that when you slice a conic,
>> you get circles, elipses, and hyperbolas.
>> https://www.andrews.edu/~calkins/math/webtexts/conicsl.jpg
>>
>> If I were a great woodworker, I would just make one.
>> But I'm not that good and I don't have a lathe.
>> All I have is a circular chop saw.
>>
>> Do you know of an easy way to make or buy conic sections (wood or plastic)?
>> https://www.andrews.edu/~calkins/math/webtexts/numb19.htm
>>
> You are half way there with the chop saw.
>
> If it would be me I would go down to Lowes and buy a piece of round wood
> stock and just cut it at different angles to show how a round circle can
> be come can become the other pieces.
any other angle, you get an ellipse. It is impossible to make a single cut through a cylinder
and get either a hyperbola or a parabola.
>
> If you can not find a piece of round wood, you could do the same thing
> with a piece of PVC pipe. After cutting you could sand the rough edges
> and actually use the Pipe as a stamp; ink it and print the circles, ,
> elipses, and hyperbolas.
No can do. You can cut hyperbolas and parabolas from a cone, but not from a cylinder.
> If you can not find a piece of round wood, you could do the same thing
> with a piece of PVC pipe. After cutting you could sand the rough edges
> and actually use the Pipe as a stamp; ink it and print the circles, ,
> elipses, and hyperbolas.
Doug Miller
Aug 20, 2016, 5:09:23 PM8/20/16
to
Aardvarks <aard...@a.b.c.com> wrote in news:npa53j$u9g$2...@gioia.aioe.org:
> I am trying to help a math teacher spruce up a barren basement classroom
> that currently looks like a prison cell.
> [...]
> I am trying to help a math teacher spruce up a barren basement classroom
> that currently looks like a prison cell.
> Do you know of an easy way to make or buy conic sections (wood or plastic)?
> https://www.andrews.edu/~calkins/math/webtexts/numb19.htm
http://lmgtfy.com/?q=buy+wooden+conic+sections#seen
> https://www.andrews.edu/~calkins/math/webtexts/numb19.htm
G.Dubois
Aug 25, 2016, 4:36:06 AM8/25/16
to
See
https://www.google.fr/search?q=c%C3%B4ne+de+signalisation&hl=fr&gbv=2&prmd=ivns&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwi-tLGUlNzOAhWGCSwKHWZRCqwQsAQIRA
and
a cilindrical hat box or similar
Good luck
GD
"Aardvarks" <aard...@a.b.c.com> a écrit dans le message de
news:npa53j$u9g$2...@gioia.aioe.org...
https://www.google.fr/search?q=c%C3%B4ne+de+signalisation&hl=fr&gbv=2&prmd=ivns&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwi-tLGUlNzOAhWGCSwKHWZRCqwQsAQIRA
and
a cilindrical hat box or similar
Good luck
GD
"Aardvarks" <aard...@a.b.c.com> a écrit dans le message de
news:npa53j$u9g$2...@gioia.aioe.org...
Aardvarks
Aug 25, 2016, 12:33:03 PM8/25/16
to
On Sat, 20 Aug 2016 21:09:22 -0000 (UTC), Doug Miller wrote:
> http://lmgtfy.com/?q=buy+wooden+conic+sections#seen
That totally and completely misses the point.
If they existed, in wood, for something like five or ten bucks (at the
most), the google search would make sense.
But the wooden ones are in the hundred-dollar range, which is over ten
times the price limit.
I guess I didn't state that from the beginning, so, I apologize for not
being clear. The goal was to find an existing "something" that can be
sliced into conic sections.
The two best existing somethings are that I have 2-inch diameter fence
posts lying around, and I have traffic cones lying around.
So both are free.
My current plan is to put my hand held belt sander in a vise to see if I
can sand the fence post into a cone. If that works, I can easily slice the
cone with the 12-inch circular chop saw - but the kerf might be a bit wide.
If the kerf is too wide, I can probably jig saw it with a hand-held jig
saw, but it might not be a good straight edge.
The great thing about the fence post is that one 8-foot length affords me a
lot of wasted scrap! And it's free.
The traffic cones are also free, since I have a few lying around, but
they're harder to cut - but they're more visually appealing, if I can
manage to cut one. I don't think can double nap the traffic cones though.
So double napping will be best done with the fence post.
If I can find a larger-diameter fence post, I will try that, as 2 inches
seems too small to be visually appealing to the room (but it could sit on
the teacher's desk).
> http://lmgtfy.com/?q=buy+wooden+conic+sections#seen
That totally and completely misses the point.
If they existed, in wood, for something like five or ten bucks (at the
most), the google search would make sense.
But the wooden ones are in the hundred-dollar range, which is over ten
times the price limit.
I guess I didn't state that from the beginning, so, I apologize for not
being clear. The goal was to find an existing "something" that can be
sliced into conic sections.
The two best existing somethings are that I have 2-inch diameter fence
posts lying around, and I have traffic cones lying around.
So both are free.
My current plan is to put my hand held belt sander in a vise to see if I
can sand the fence post into a cone. If that works, I can easily slice the
cone with the 12-inch circular chop saw - but the kerf might be a bit wide.
If the kerf is too wide, I can probably jig saw it with a hand-held jig
saw, but it might not be a good straight edge.
The great thing about the fence post is that one 8-foot length affords me a
lot of wasted scrap! And it's free.
The traffic cones are also free, since I have a few lying around, but
they're harder to cut - but they're more visually appealing, if I can
manage to cut one. I don't think can double nap the traffic cones though.
So double napping will be best done with the fence post.
If I can find a larger-diameter fence post, I will try that, as 2 inches
seems too small to be visually appealing to the room (but it could sit on
the teacher's desk).
Aardvarks
Aug 25, 2016, 12:33:04 PM8/25/16
to
On Sat, 20 Aug 2016 21:06:46 -0000 (UTC), Doug Miller wrote:
> It can't. If you cut a cylinder perpendicular to its axis, you get a circle. If you cut a cylinder at
> any other angle, you get an ellipse. It is impossible to make a single cut through a cylinder
> and get either a hyperbola or a parabola.
You just gave me a great idea!
> It can't. If you cut a cylinder perpendicular to its axis, you get a circle. If you cut a cylinder at
> any other angle, you get an ellipse. It is impossible to make a single cut through a cylinder
> and get either a hyperbola or a parabola.
My original (and main) goal is to figure out where I can find a cheap cone
to slice into conic sections.
However, at the same time, I can get a similar diameter "dowel" and show
exactly what you just said!
I think, I might try a 2-inch diameter soft wood fence post.
What I can do is put my belt sander into a vise and then use that belt
sander to sand the soft fence-post wood into a cone.
It might look fugly - in which case I'll have to scrap the idea, but if it
works, I can then slice the resulting cone into the conic sections.
Then I can slice the original fence post into sections to show that what
you get out of a cylinder is different than what you get out of a cone.
I think this is a GREAT IDEA as it has to be cheap (my time is not worth
much, but my money is).
Aardvarks
Aug 25, 2016, 12:33:05 PM8/25/16
to
On Sat, 20 Aug 2016 14:12:53 -0400, Keith Nuttle wrote:
> You are half way there with the chop saw.
>
> If it would be me I would go down to Lowes and buy a piece of round wood
> stock and just cut it at different angles to show how a round circle can
> be come can become the other pieces.
>
> If you can not find a piece of round wood, you could do the same thing
> with a piece of PVC pipe. After cutting you could sand the rough edges
> and actually use the Pipe as a stamp; ink it and print the circles, ,
> elipses, and hyperbolas.
I don't think a cylinder will work but I guess I could put a cylinder
> You are half way there with the chop saw.
>
> If it would be me I would go down to Lowes and buy a piece of round wood
> stock and just cut it at different angles to show how a round circle can
> be come can become the other pieces.
>
> If you can not find a piece of round wood, you could do the same thing
> with a piece of PVC pipe. After cutting you could sand the rough edges
> and actually use the Pipe as a stamp; ink it and print the circles, ,
> elipses, and hyperbolas.
against my belt sander and have the belt sander (in a vise) turn the
cylinder into a cone.
Then I could slice the cone into the conic sections.
I have an old 2-inch diameter fence post that I might try that on.
I was hoping for a large conic section (like 12 inch diameter) but I can't
sand a 12-inch diameter dowel with a belt saw.
Aardvarks
Aug 25, 2016, 12:33:07 PM8/25/16
to
On Sat, 20 Aug 2016 13:58:30 -0400, burfordTjustice wrote:
> Google
Google doesn't find the answer to the question unless the *exact* question
was asked.
For example, G. Dubois suggested traffic cones, which would never be found
simply by googling for conic sections for a math class.
And, googling for conic sections for a math class finds the stuff that dpb
found, which are absolutely gorgeous and perfect - but they cost $100 which
is out of the picture.
So, google doesn't always work.
It fails when the constraints are different than the norm.
In this case, "cost" is a huge constraint.
Theft is also a constraint (where the traffic cone excels).
Size is also a constraint (the bigger the better in this case).
So, my point is that google didn't find that which I seek.
Google doesn't find the answer to the question unless the *exact* question
was asked.
For example, G. Dubois suggested traffic cones, which would never be found
simply by googling for conic sections for a math class.
And, googling for conic sections for a math class finds the stuff that dpb
found, which are absolutely gorgeous and perfect - but they cost $100 which
is out of the picture.
So, google doesn't always work.
It fails when the constraints are different than the norm.
In this case, "cost" is a huge constraint.
Theft is also a constraint (where the traffic cone excels).
Size is also a constraint (the bigger the better in this case).
So, my point is that google didn't find that which I seek.
Aardvarks
Aug 25, 2016, 12:33:09 PM8/25/16
to
On Sat, 20 Aug 2016 12:55:28 -0500, dpb wrote:
> <http://www.eaieducation.com/Product/532031/Dissectible_Conic_Section_Model.aspx>
>
> Now, what they're asking for them may not fit the budget...
I was hoping to figure out a cheap way to just give them to her, but the
> <http://www.eaieducation.com/Product/532031/Dissectible_Conic_Section_Model.aspx>
>
> Now, what they're asking for them may not fit the budget...
ones you showed at that site were gorgeous!
http://www.eaieducation.com/Product/532031/Dissectible_Conic_Section_Model.aspx
At $100 each, they're a bit pricey for *me* to spend just to help someone
out, and maybe she'd even have a problem expensing them at a public school,
but they *are* perfect (and gorgeous!) and made out of wood, which is
fantastic.
If I had a lathe, I'd just take a light colored wood and a dark colored
wood and make two single-napped cones.
Then I'd slice each cone four ways with a thin jig saw blade (I only have a
hand-held jig saw though), and that would be what you see in that picture
you found.
http://www.eaieducation.com/images/products/532031_L.jpg
So, with a lathe and a jig saw, it would be easy.
But without a lathe, I'd need the cone to exist in a material I could cut
(plastic or wood most likely) with a hand-held jig saw or circular saw.
Aardvarks
Aug 25, 2016, 12:33:11 PM8/25/16
to
On Sat, 20 Aug 2016 13:54:09 -0400, Retired wrote:
> Here is one:
>
> http://www.didax.com/shop/searchresults.cfm/Keyword/conic%20sections.cfm
That is good for the math class.
> Here is one:
>
> http://www.didax.com/shop/searchresults.cfm/Keyword/conic%20sections.cfm
http://www.didax.com/shop/productdetails.cfm/Keyword/conic%20sections/Sort/Item/Order/Asc/StartRow/1/ShowAll/No/ItemNo/333311.cfm
At $30, it's best for the teacher to expense it.
So I'll see if they'll let her do that.
She's new to teaching and is shy and far too timid (IMHO), since this is a
good request, I think, for a math teacher.
I'm just trying to help her out.
Aardvarks
Aug 25, 2016, 12:33:13 PM8/25/16
to
On Thu, 25 Aug 2016 10:36:02 +0200, G.Dubois wrote:
> See
>
> https://www.google.fr/search?q=c%C3%B4ne+de+signalisation&hl=fr&gbv=2&prmd=ivns&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwi-tLGUlNzOAhWGCSwKHWZRCqwQsAQIRA
Those traffic cones are a GREAT idea for visual aids to show conic sections
in a classroom!
For one thing, they're bright orange, and pretty big (so the kids won't
steal them) and they're rubbery (so nobody is going to get stabbed by one),
and they have a nice base (so they will stay in a corner) and they are
visually unusual (so the kids will remember them for decades).
It's probably too hard to double-nap them, but as a single-napped cone,
they are a great idea. I even have some spares I can cut open for the kids
to see. I'll check that out.
Thank you for that great idea.
I knew there were be conics lying around the house!
> See
>
> https://www.google.fr/search?q=c%C3%B4ne+de+signalisation&hl=fr&gbv=2&prmd=ivns&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwi-tLGUlNzOAhWGCSwKHWZRCqwQsAQIRA
Those traffic cones are a GREAT idea for visual aids to show conic sections
in a classroom!
For one thing, they're bright orange, and pretty big (so the kids won't
steal them) and they're rubbery (so nobody is going to get stabbed by one),
and they have a nice base (so they will stay in a corner) and they are
visually unusual (so the kids will remember them for decades).
It's probably too hard to double-nap them, but as a single-napped cone,
they are a great idea. I even have some spares I can cut open for the kids
to see. I'll check that out.
Thank you for that great idea.
I knew there were be conics lying around the house!
Vic Smith
Aug 25, 2016, 1:04:28 PM8/25/16
to
On Thu, 25 Aug 2016 16:33:00 +0000 (UTC), Aardvarks
<aard...@a.b.c.com> wrote:
>On Sat, 20 Aug 2016 21:09:22 -0000 (UTC), Doug Miller wrote:
>
>> http://lmgtfy.com/?q=buy+wooden+conic+sections#seen
>
>That totally and completely misses the point.
>If they existed, in wood, for something like five or ten bucks (at the
>most), the google search would make sense.
Well, they do.
<aard...@a.b.c.com> wrote:
>On Sat, 20 Aug 2016 21:09:22 -0000 (UTC), Doug Miller wrote:
>
>> http://lmgtfy.com/?q=buy+wooden+conic+sections#seen
>
>That totally and completely misses the point.
>If they existed, in wood, for something like five or ten bucks (at the
>most), the google search would make sense.
FromTheRafters
Aug 25, 2016, 1:48:41 PM8/25/16
to
Aardvarks explained :
I once found some nice partial cones in a dumpster outside a textile
mill. Spindle cones I think they are called. They were hollow, and the
tip was truncated, but they were as cheap as you can get I think.
mill. Spindle cones I think they are called. They were hollow, and the
tip was truncated, but they were as cheap as you can get I think.
Aardvarks
Aug 26, 2016, 1:20:46 PM8/26/16
to
On Thu, 25 Aug 2016 12:04:21 -0500, Vic Smith wrote:
> Well, they do.
Wood cones for ten bucks?
Where?
> Well, they do.
Wood cones for ten bucks?
Where?
Vic Smith
Aug 26, 2016, 5:05:24 PM8/26/16
to
Google search bar. But I'd consider "foam cones" myself.
Aardvarks
Aug 27, 2016, 6:23:40 AM8/27/16
to
On Fri, 26 Aug 2016 16:05:18 -0500, Vic Smith wrote:
> I can't be making decisions for you. Just type "wood cones" in the
> Google search bar. But I'd consider "foam cones" myself.
I picked up some plaster of paris today and will try to make the cones that
> I can't be making decisions for you. Just type "wood cones" in the
> Google search bar. But I'd consider "foam cones" myself.
way and cut them with a jig saw.
That's the cheapest way I think, and I thank you for the suggestions.
Colonel Edmund J. Burke
Aug 27, 2016, 12:53:05 PM8/27/16
to
On 8/20/2016 10:47 AM, Aardvarks wrote:
> I am trying to help a math teacher spruce up a barren basement classroom
> that currently looks like a prison cell.
I gots some "wood" fer ya.
> I am trying to help a math teacher spruce up a barren basement classroom
> that currently looks like a prison cell.
LOL
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