Iced Tea Phenomenon - RF Cafe Forums

Greetings:

I have no earth-shattering discovery to report here, but did just observe an interesting phenomena. For a long time I have been making the same kind of instant iced tea at work that I do at home, and noticed that at work, the powder clumps on the top of the water (even if put in the cup before putting in the water), but it does not do so at home.

Today I discoverd the secret. At work, I always use a plastic spoon. It was "cool" to see how the iced tea powder particles arranged themsevles on the spoon like iron filings around a magnet, with tendrils sticking out everywhere. Evidently, a triboelectric charge is created by thrusting the spoon into the powder. Today, however, I used a metal spoon (brought in from home for soup), and immediately saw that the powder did not assume a static charge and display the patterns. When I dropped the powder onto the top of the water, it spread out and began to sink, rather than float and clump.

It was a voila! moment for me. I'll be using a metal spoon from now on.


- Kirt Blattenberger

I smell a Nobel Prize in physics here!

Just discharge the plastic spoon before using it! Sheesh!

Greetings Nikola:

Since plastic is an insulator, discharging it with a ground wire is not possible. I suppose it could be held in front of an ionizer prior to dipping it in the powder, but I just don't happen to have an ionizer in my cubicle. Looks like I'll have to stick with the metal spoon.


- Kirt Blattenberger

Kirt,

Facinating, I wonder if that could have some effect when making chocolate milk for my kids. That powder always clumps and takes vigourous stirring to mix. I know that in chocolate milk, the clumping is dominated by the cocoa powder/suface tension of the milk interactions. But I wonder if some simple way of charging the spoon pre mixing could mitigate this. Say hooking the spoon up to the positive side of a battery and mixing in a grounded metal cup.

OTOH, I do remember using a spoon to scoop up the unmixed blobs of chocolate on top of my milk when i was a kid, so maybe there is no problem.

I have heard that the japanese have a tradition of useless inventions called Chindogu.

Anyway, I solved your problem by drinking coffee.

In order to avoid that chocolate powder clumps you first have to mix the powder with a little bit water and only after that you add the milk.
Unmixed blobs of chocolate on top of your milk will be a thing of your past

OK - so I already learned the hard way to NEVER use a vacuum cleaner on a PC interior, because the static charge on the end of the plastic nozzle gets to 40kV+ , but they get reallyyuk, and the blown air method chucks all manner of mite crap, human skin particles and other stuff all over the place.

While using some adhesive-backed copper tape (EMC screen on a proto!), I got the idea to tape a strip along the push-on nozzle, and tuck a bit inside the nozzle entry to make a discharge path to the metal curved part, and hence to my hand. OK, all goes well, but this cleaner is Mr. Dysan's best. No bag! You take it apart and tip the dust out of the plastic cyclonic thing. The dust won't leave. Its all charged up and stays stuck to the plastic! So I take a tissue, clutch the plastic bin, and stick my hand in to give it a wipe. BAM! I get floored by a static shock that sounded an audible crack as I put my hand in.

Know that the construction of a Dysan cleaner plastic dirt collector is a Leydon Jar capacitor that becomes a nasty thing when you wrap your conductive arm around the outside, and offer it the connected low potential of your body near it, and then try and stick the other connected arm inside.

Like Kirt's spoon, the vac I use now is quiet, powerful, and made of metal!

When was it called back?