Untitled
sandman-kk: This animation suggests one way to draw a perfect ellipse by hand. Place two drawing pins in a board, and tie a piece of string around them (the red dotted lines in the picture). If you pull the string tight with a pen, then the curve you will get is an ellipse.  This means that the total length of the two red lines is constant. The two pins are at the foci of the ellipse, special points.  Planetary orbits are ellipses, with the Sun at a focus.  What would happen if you moved the pins closer and closer to each other? [code] [more]

sandman-kk:

This animation suggests one way to draw a perfect ellipse by hand. Place two drawing pins in a board, and tie a piece of string around them (the red dotted lines in the picture). If you pull the string tight with a pen, then the curve you will get is an ellipse.  This means that the total length of the two red lines is constant. The two pins are at the foci of the ellipse, special points.  Planetary orbits are ellipses, with the Sun at a focus.  What would happen if you moved the pins closer and closer to each other? [code] [more]

Reblogged 9 months ago from plasticdreams (Originally from matthen)
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Source: matthen
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    This animation suggests one way to draw a perfect ellipse by hand. Place two drawing pins in a board, and tie a piece of...
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