Hele Shaw Cell with Magnetic Fluid

Latest Results

The shapes of self organizing structures that are formed by magnetic fluid under the influence of a homogenious field with variable strength are interesting to study. When the concentration of the solution and the velocity of the field change are in a good relation the forms show a behaviour that will be predictable in its parameters.

A major difference exists when the drop of fluid is a single drop in one case and a cluster of bubbles in the other.

The single drop converts into a star shape with many arms fig0a, fig 0b.. In case of bubbles the bubbles become wrinkled keping their volume over the cyclus of strngthening the field and lowering the intensity again, fig 0c.

http://www.youtube.com/watch?v=mY0StFgJ3eo http://www.youtube.com/watch?v=ZfdQzh2hG3o

fig 0a Changing the structure by changing field strength
fig 0b Changing structure with thinned fluid
fig 0d Elevator with magnet to provide variable field strength
fig 0c Changing the structure with closed bubbles
How to make a Hele Shaw Cell


As shown in figure 1 the ingredients are: cover slips with glass, small rubber rings, paper clips and just a few drops of magnetic fluid. Figure 1 also shows thin plastic straws and a magnet together with the magnetic fluid for better handling, tissue paper should be added.

fig 1 ingredients

In the preparation the cover is opened and a rubber ring is placed inside the area of the glass. Inserting a white piece of paper under the lower glass provides a good background for the obervation.

For handling the magnetic fluid with a straw as pipette it is helpful to divide the magnetic fluid inside the test tube and to bring one drop of it up close to the opening of the tube to pick it up from there.

As the cover slip will not hold by itself it will be kept shut with the paper clips. Those clips shall be widened before pushing them over the frame as they might break the glass if they are to tight.

fig 4 Result
fig 2 Preparation of the cover slip
fig 3 Separating the fluid inside the tube with a magnet.


The result is a Hele Shaw cell that shows very small peaks of fluid under a strong vertical magnetic field.

When the field is weaker the fluid touches the upper glass and the peaks are flattened, in other reginos with more material the fluid joins to lines, vertical walls that are oriented in the direction of the horizontal component of the field.

At some locations the lines are closed at the border of the round magnet underneath, at other locations they are open, a bubble might be enclosed by the lines.

It is also interesting to watch the behavior of the structure when the position of the magnet under the cell changes.


fig 6 Self forming structure of magnetic fluid in vertical megnetic field