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Putting ballpoint pen ink on the tip of a leaf then putting it on water (or milk if you want it to stand out) causes the leave to whizz around leaving trail of ink behind.

Here's the video I did with Matt using oleic acid to calculate pi:
https://youtu.be/lmgCgzjlWO4

Here's my spinning glue video:
https://youtu.be/38XWz1IL6j8

You can buy my books here:
https://stevemould.com/books

You can support me on Patreon here:
https://www.patreon.com/stevemould

just like these amazing people:

Frank Hereford
Will Ackerly
Brendan Williams
Matthew Cocke
Frederic Merizen
Joel Van der loo
Glenn Watson
Doug Peterson
Paul Warelis
John Zelinka
Alnitak
Grant Hay
Heather Liu
Marshall Fitzpatrik
Lukas Biewalk
JJ Masson
Ben McIntosh
Damien Szerszinski

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