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 nicholasjbennett@hotmail.com escribió: 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 To: Mailinglist Squeakland 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 -
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