I use my flute headjoint as a tone production device.
Seriously, no I've never tried this. When I was first learning flute, I just used the headjoint alone to practice tone production. It worked for me, and it came free with my flute!
Or go to: http://www.blockiflute.com/pneumopro.html
It looks like a gimmick which has no actual sound but the one tube (or bar?) has 4 propellers on it that spin when you blow air.
My problem with this (besides the ~$56 out of my pocket) is that the need to focus the airstream is missing if the sound isn't produced. I would say that one could do the same trick with a 2nd person holding a small candle in the sirstream at a safe distance after the airstream leaves the flute head.
I'd think that one can do more good with a mirror on the music stand and a good set of ears.
Blow straight ahead into the palm of a hand, about 6-8 cm away. While blowing, use the index finger of the other hand against the lower lip, as if it were the flute's lip plate.
Note how if you are still blowing straight ahead, the direction of the airstream will have moved down on your palm. This shows that the presence of the embouchure plate against the lip actually diverts the airstream down quite a lot?
I agree with Bimbo.
Perhaps that toy would show the same thing.
<Added>
Bad boy! Write that 100 times...
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I tried that once at a rock gig, albeit with cigarettes. It was kinda cool to see the smoke drift out of the tone holes. Played absolute havoc with my pads though. The suckers were perma-sticky afterwards. I never did that again (while sober anyways).
BTW, I used an old beater flute for that particular trick. I never hauled the "good" flute into a bar. I'm not THAT stoopid, even after a few ;-)