Leidenfrost Effect Physics Project Ideas & Rotating Motion Explanation

[coolie]

Can someone give me some ideas on my current physics Project
I am currently measureing the effect of temperature of a hot plate on the life time of a water droplet!
But I am looking of some realistic ideas on other variables that i can change on top of the leidenfrost effect.
Also I am abserving this rotating motion of the suspending liquid, where it spins with a star characteristic. Does anyone know why this happen?
Thank you,
You can write to me vis email : dragoon.li@gmail.com

 

[Astronuc]

Also I am abserving this rotating motion of the suspending liquid, where it spins with a star characteristic.

What does "star characteristic" mean?

It could simply mean that surface tension or liquid cohesiveness in the drop is not azimuthally uniform, which is quite natural and expected.

 

[Astronuc]

Usefuel reference - http://en.wikipedia.org/wiki/Leidenfrost_Effect

and

http://www.wiley.com/college/phy/halliday320005/pdf/leidenfrost_essay.pdf

The Leidenfrost point (LFP) is the minimum surface temperature required to support film boiling, and film boiling is undesirable in a heat exchanger because the vapor phase has a significantly lower heat transfer coefficient (lower thermal conductivity), which will result in higher temperatures on the heated surface which is being cooled by boiling liquid. Higher temperatures can lead to premature or catastropic structural failure, and in aqueous systems, lead to corrosion which degrades heat transfer properties, and can degrade structural integrity.

 

[karmacelina]

this phenomenon that you've observed has been observed and studied by others -- the star pattern is called a "leidenfrost star"... which was "discovered" in the 50s by holter and glasscock.

here's the reference:

N. Holter and W. Glasscock, “Vibrations of evaporating liquid drops,”
J. Ac. Soc.
Am., vol. 24, no. 6, pp. 682–686, 1952.

hope this helps.