So yeah, I’m not completely sure as to how this works – it seems he’s just adding some drops of water, according to the video description. Anyone care to give us a run-down of the science behind this?
[Meanwhile in Russia]
Check "The Spangler Effect" for how to do this. From what my wife & kids say, it has to do with the capillary effect–the wood pulls in the water and it expands the wood which makes the sticks move.
Yeah, it only works because the matches are snapped :) The water moves through the match at the break point by osmosis, resulting in expansion; this causes the matches to flex as their hinge fills with fluid and seeks to form its proper linear structure.
I have a similar trick (suitable for diners) where you take a straw wrapper, rip it longways except for a half-inch middle section and twist the ends to make a four legged "spider". Then, if you drip water on it, you can watch it "walk".
Go on, entertain your children.