sun-earth-moon
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Is it possible to squeak planetary motion? Obviously, you can rotate the
earth about the sun by repositioning the earth's rotation center to the center of the sun, but what about moving the moon about the (rotating) earth? If a sketch's rotation center had its x,y location exposed as tiles then there could possibly be an elegant solution, but otherwise...? While conducting another workshop with the Girl Scouts last night, Charlie, my co-worker, came up with another scheme which I liked, to approximate circular motion. It consisted of: earth turn toward sun earth turn by 90 forward I liked this idea of a simple "tangent" and, if it worked as hoped, you could extend it to the moon-earth too. However, we see that it's not exactly an "instantaneous tangent" :) http://poincare.uits.iupui.edu/~heiland/squeak/planets Ideas? Thanks, Randy Btw, I had a quick look at Randall Caton's excellent Squeak pages, http://www.pcs.cnu.edu/~rcaton/extrasolar/students.html , but didn't see anything that addressed this topic -- or maybe I just didn't dig deep enough. _______________________________________________ Squeakland mailing list [hidden email] http://squeakland.org/mailman/listinfo/squeakland |
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Am 16.02.2006 um 16:43 schrieb Randy Heiland:
> Is it possible to squeak planetary motion? Yes. You have to embed the moon into the earth (you find "embed" in the halo menu). Then, when you move the earth, the moon already moves with it. Here's an example: http://squeakland.org/project.jsp?http://impara.de/~bert/projects/ Sonne-Erde-Mond.001.pr - Bert - _______________________________________________ Squeakland mailing list [hidden email] http://squeakland.org/mailman/listinfo/squeakland |
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Wow, this looks promising! I thought I knew embedding, but apparently not.
In my sun-earth-moon project, I have the earth away from the sun but its rotCenter inside the sun and when I bring up the earth's embed submenu, I see 'sun' (not 'moon'). However, when do the analogous thing with the moon/earth, all I see in the moon's embed submenu is 'PasteUpMorph' and 'SketchMorph' - no 'earth' or 'sun'. What's up? Currently these sketches live in the World, not in a playfield. --Randy > -----Original Message----- > From: Bert Freudenberg [mailto:[hidden email]] > Sent: Thursday, February 16, 2006 1:08 PM > To: Mailinglist Squeakland > Cc: Randy Heiland > Subject: Re: [Squeakland] sun-earth-moon > > Am 16.02.2006 um 16:43 schrieb Randy Heiland: > > > Is it possible to squeak planetary motion? > > Yes. You have to embed the moon into the earth (you find "embed" in > the halo menu). Then, when you move the earth, the moon already moves > with it. > > Here's an example: > > http://squeakland.org/project.jsp?http://impara.de/~bert/projects/ > Sonne-Erde-Mond.001.pr > > - Bert - _______________________________________________ Squeakland mailing list [hidden email] http://squeakland.org/mailman/listinfo/squeakland |
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In reply to this post by Randy Heiland
randy,
I had done a sun earth moon system once and found that one could set the rotation center fairly easily (I think one of the halo menu choices maybe, also there I think you can tell it to display the rotation center and the forward vector which can help visualize things). I had used the embedding as described below, but found that if I simply embedded earth in sun the earth would be 'unselectable' when it did not overlap with the sun - which made it awkward if you wanted to go back and add the moon later. I ended up painting the 'orbit center' of my 'orbiters' as a small dot in the orbiters sketch - a bit strange maybe but it made it very clear where the rotation center should be and ensured that the orbiters stayed selectable when embedded. regards, nicholas >From: Bert Freudenberg <[hidden email]> >To: Mailinglist Squeakland <[hidden email]> >Subject: Re: [Squeakland] sun-earth-moon >Date: Thu, 16 Feb 2006 19:08:22 +0100 > >Am 16.02.2006 um 16:43 schrieb Randy Heiland: > > > Is it possible to squeak planetary motion? > >Yes. You have to embed the moon into the earth (you find "embed" in >the halo menu). Then, when you move the earth, the moon already moves >with it. > >Here's an example: > > http://squeakland.org/project.jsp?http://impara.de/~bert/projects/ >Sonne-Erde-Mond.001.pr > >- Bert - > >_______________________________________________ >Squeakland mailing list >[hidden email] >http://squeakland.org/mailman/listinfo/squeakland _______________________________________________ Squeakland mailing list [hidden email] http://squeakland.org/mailman/listinfo/squeakland |
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In reply to this post by Randy Heiland
Alan Kay has also done some very nice "falling body" simulations --
perhaps we can send a few around. Kim At 1:40 PM -0500 2/16/06, Randy Heiland wrote: >Wow, this looks promising! I thought I knew embedding, but apparently not. >In my sun-earth-moon project, I have the earth away from the sun but its >rotCenter inside the sun and when I bring up the earth's embed submenu, I >see 'sun' (not 'moon'). However, when do the analogous thing with the >moon/earth, all I see in the moon's embed submenu is 'PasteUpMorph' and >'SketchMorph' - no 'earth' or 'sun'. What's up? Currently these sketches >live in the World, not in a playfield. > >--Randy > >> -----Original Message----- >> From: Bert Freudenberg [mailto:[hidden email]] >> Sent: Thursday, February 16, 2006 1:08 PM >> To: Mailinglist Squeakland >> Cc: Randy Heiland >> Subject: Re: [Squeakland] sun-earth-moon >> >> Am 16.02.2006 um 16:43 schrieb Randy Heiland: >> >> > Is it possible to squeak planetary motion? >> >> Yes. You have to embed the moon into the earth (you find "embed" in >> the halo menu). Then, when you move the earth, the moon already moves >> with it. >> >> Here's an example: >> >> http://squeakland.org/project.jsp?http://impara.de/~bert/projects/ >> Sonne-Erde-Mond.001.pr >> >> - Bert - > > >_______________________________________________ >Squeakland mailing list >[hidden email] >http://squeakland.org/mailman/listinfo/squeakland _______________________________________________ Squeakland mailing list [hidden email] http://squeakland.org/mailman/listinfo/squeakland |
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In reply to this post by Nicholas Bennett
Shift-Halo-Click works easiest for me.
- Bert - Am 16.02.2006 um 22:59 schrieb Nicholas Bennett: > randy, > > I had done a sun earth moon system once and found that one could > set the > rotation center fairly easily (I think one of the halo menu choices > maybe, > also there I think you can tell it to display the rotation center > and the > forward vector which can help visualize things). > > I had used the embedding as described below, but found that if I > simply > embedded earth in sun the earth would be 'unselectable' when it did > not > overlap with the sun - which made it awkward if you wanted to go > back and > add the moon later. I ended up painting the 'orbit center' of my > 'orbiters' > as a small dot in the orbiters sketch - a bit strange maybe but it > made it > very clear where the rotation center should be and ensured that the > orbiters > stayed selectable when embedded. > > regards, > nicholas > > >> From: Bert Freudenberg <[hidden email]> >> To: Mailinglist Squeakland <[hidden email]> >> Subject: Re: [Squeakland] sun-earth-moon >> Date: Thu, 16 Feb 2006 19:08:22 +0100 >> >> Am 16.02.2006 um 16:43 schrieb Randy Heiland: >> >>> Is it possible to squeak planetary motion? >> >> Yes. You have to embed the moon into the earth (you find "embed" in >> the halo menu). Then, when you move the earth, the moon already moves >> with it. >> >> Here's an example: >> >> http://squeakland.org/project.jsp?http://impara.de/~bert/projects/ >> Sonne-Erde-Mond.001.pr >> >> - Bert - >> >> _______________________________________________ >> Squeakland mailing list >> [hidden email] >> http://squeakland.org/mailman/listinfo/squeakland > > > _______________________________________________ > Squeakland mailing list > [hidden email] > http://squeakland.org/mailman/listinfo/squeakland _______________________________________________ Squeakland mailing list [hidden email] http://squeakland.org/mailman/listinfo/squeakland |
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In reply to this post by Nicholas Bennett
Another approach:
I'm using this simulation in Primary School, third level (eight years old). Children try to simulate [1] Eatrh's spin on his axis and [2] Eatrh's rotate around the Sun. Well, this is very interesting because a lot of them still think the sun rotate around the Earth!! With basic eToy, the construct and investigate these two processes. First they paint a circular solid Base and then embed the Earth in this Base (Randy's solution is amazing but they don't know degrees). [1] Go and Rotate for Base scketch [2] Only Rotate for the Earth Fernando. Nicholas Bennett <[hidden email]> escribió: randy,
LLama Gratis a cualquier PC del Mundo. Llamadas a fijos y móviles desde 1 céntimo por minuto. http://es.voice.yahoo.com _______________________________________________ Squeakland mailing list [hidden email] http://squeakland.org/mailman/listinfo/squeakland |
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