Ferro Fluid Demonstration Cell


Downloads: Download a movie of Ferro Fluid under the influence of a changing magnetic field (opens in a new window, 1M, opens with Quicktime). Download the free Quicktime player		Ferro Fluid Demonstration Cell Although harmless, Ferro Fluid is somewhat viscous and messy. This demonstration cell allows you to manipulate and observe the amazing properties of Ferro Fluid without the risk of spills and stains. For best results, use a small glass vial (e.g. G7.06). Partly fill the vial with a suitable clear liquid such as aqueous ethanol. Carefully add approximately 1mL of Ferro Fluid then top up with clear liquid. Hints: Avoid low polarity clear liquids such as 95% ethanol. They will tend to dissolve the Ferro Fluid and cause the magnetic particles to separate. Avoid high polarity clear liquids such as 100% water. The high inter-surface tension caused by polar liquids suppresses the reaction of the Ferro Fluid in a magnetic field. Try different clear liquids and blends to get the best results. For example, compare a 25% ethanol solution with a 70% ethanol solution. The "spiked" shape is a result of a compromise between the inter-surface tension between the Ferro Fluid and the clear liquid that acts to minimise the exposed surface area, and the magnetic forces that act to align the dispersed particles in the magnetic field. The stronger the magnetic field (the closer the magnet) or the lower the inter-surface tension (the closer the polarity of the liquids in the vial), the more spikes (the greater the exposed surface area). You might see a tendency for the Ferro Fluid to adhere to the glass walls of the vial. One way to reduce this is to coat the interior of the vial with 1-2mL of glycerol before adding the clear liquid and Ferro Fluid. Being viscous, the glycerol coating tends to act as a barrier. Avoid shaking your demonstration cell. As globules of Ferro Fluid coalesce after shaking, they will tend to occlude the clear liquid. Mixing the liquids in this way will reduce the visual effect. Store your Demonstration Cell upside down so the Ferro Fluid accumulates in the cap of the vial where it is less likely to stain the glass. Clear plastic vials are likely to stain because of their affinity for the Ferro Fluid.

Although harmless, Ferro Fluid is somewhat viscous and messy. This demonstration cell allows you to manipulate and observe the amazing properties of Ferro Fluid without the risk of spills and stains.

For best results, use a small glass vial (e.g. G7.06). Partly fill the vial with a suitable clear liquid such as aqueous ethanol. Carefully add approximately 1mL of Ferro Fluid then top up with clear liquid.