Science News
from research organizations

Levitating foam liquid under the spell of magnetic fields

Date:
November 11, 2013
Source:
Springer Science+Business Media
Summary:
No better solution to studying ever-draining foams than applying a strong magnetic field to keep the liquid in the foam at a standstill by levitating its water molecules. Foams fascinate, partly due to their short lifespan. Foams change as fluid drains out of their structure over time. It is precisely their ephemeral nature which has, until now, prevented scientists from experimentally probing their characteristic dynamics further. Instead, foams have often been studied theoretically. Now scientists have devised a method of keeping foams in shape using a magnet, which allows their dynamics to be investigated experimentally.
Share:
       
FULL STORY

No better solution to studying ever-draining foams than applying a strong magnetic field to keep the liquid in the foam at a standstill by levitating its water molecules

Foams fascinate, partly due to their short lifespan. Foams change as fluid drains out of their structure over time. It is precisely their ephemeral nature which has, until now, prevented scientists from experimentally probing their characteristic dynamics further. Instead, foams have often been studied theoretically. Now, Nathan Isert from the University of Konstanz, Germany and colleagues, have devised a method of keeping foams in shape using a magnet, which allows their dynamics to be investigated experimentally, as recently described in The European Physical Journal E.

To find a way around the issue of drainage, the authors used the so-called diamagnetic levitation technique. This approach exploits the fact that water-which is one of the main components of foams-has a characteristic called diamagnetism. This means that water molecules can become magnetised in the opposite direction to an applied magnetic field. Hence, a strong magnetic field can be used to levitate the water in a foam within the bore of a magnet of 18 Tesla in strength. This prevents drainage and allows a very high level of liquid to be maintained in the foam.

Isert and colleagues have used this approach to study the coarsening behaviour of foams with greatly varying liquid fractions. As a result, they experimentally verified the decades-old theoretical predictions for the growth in bubble size for dry as well as liquid foams. They found that for a liquid fraction of about 30%-which corresponds to a foam with bubbles which start to no longer touch-the gas exchange between bubbles and the corresponding growth laws changes.

Next, they will study how the local microscopic dynamics influences the foam's global dynamics. This is of particular interest when the foam transitions from a liquid to a solid form.


Story Source:

The above post is reprinted from materials provided by Springer Science+Business Media. Note: Materials may be edited for content and length.


Journal Reference:

  1. N. Isert, G. Maret, C. M. Aegerter. Coarsening dynamics of three-dimensional levitated foams: From wet to dry. The European Physical Journal E, 2013; 36 (10) DOI: 10.1140/epje/i2013-13116-x

Cite This Page:

Springer Science+Business Media. "Levitating foam liquid under the spell of magnetic fields." ScienceDaily. ScienceDaily, 11 November 2013. <www.sciencedaily.com/releases/2013/11/131111091520.htm>.
Springer Science+Business Media. (2013, November 11). Levitating foam liquid under the spell of magnetic fields. ScienceDaily. Retrieved September 1, 2015 from www.sciencedaily.com/releases/2013/11/131111091520.htm
Springer Science+Business Media. "Levitating foam liquid under the spell of magnetic fields." ScienceDaily. www.sciencedaily.com/releases/2013/11/131111091520.htm (accessed September 1, 2015).

Share This Page: