Jire 3 years ago Needing help with finding an experiment! *It must feature ferrofluid*

1. Jire

Note that I will actually have to conduct the experiment in regular laboratory conditions. Basically I want to find an experiment where I do something with ferrofluid, a liquid full of tiny magnetic particles that can change for example the shape of still ferrofluid or its flowing speed (and flowing direction even, if I'm guessing right?) Anyway, the experiment must prove (or suggest the reliability of a theory on fluids/ferrofluid) a physical property of ferrofluid. An example experiment would be such where I would have ferrofluid and I use an electromagnet to affect the flowing speed of the liquid by altering the force it applies to the ferrofluid (a reaction in terms of flowing speed of the ferrofluid due to force being applied to its magnetic part that is, the submerged tiny magnetic particles). THE PROBLEM is that I need to do something that I can measure which is really hard because magnetic field is not strictly to one direction in practice. Can someone help me find an experiment on ferrofluid that I could write my 4000 word essay of physics on? Thank you so much in advance - this is really really hard.

2. theEric

3. theEric

If you have any way of calculating what the shape of the ferrofluid should be on a thin plate over a magnet, that would be direct... Change some variables.

4. theEric

Or maybe have a magnet on a thin plate and have the fluid underneath, and calculate how strong the force holding the plate up is. Then show that your calculation is correct by adding weight to the plate until it crashes down into a bag or something. But I don't know how you would go about calculating that.

5. Jire

First of all many thanks for taking the time to answer with such detailed ideas. As for what you suggested in your first model you said: "You can calculate the expected deviation of acceleration/average velocity/time taken to travel a distance as compared to how the fluid flows without the presence of the magnetic field.". In practice how could I make this happen? Say, we have for example a long-ish thin open glass tube tilted 45 degrees and through this flows ferrofluid with a certain velocity (neglecting the troublesome aspects of keeping the ferrofluid input constant for now). Now, given the precise composition of the ferrofluid and the theoretical interaction between it and the walls of the open glass tube (giving rise to the slowing down of the fluid due to friction? I'm not even sure) we would come into a certain conclusion of the velocity of the fluid inside the tube. Here comes the tricky part. If you were to place a magnet anywhere in the system where the ferrofluid flow occurs, where would you place it and why if you were to find out how magnetic field force affects ferrofluid flow speed? Having said that how would the magnetic field generator be aligned with respect to the tube for us to be possible to have a theoretical model of the flow speed of the ferrofluid altered by magnetic fields of varying strengths? Additionally, I don't know if I'll be able to access hi-tech equipment so I was considering using the rate of change of mass of ferrofluid dripped down from the other end of the tube as the indication of frequency of flow of the ferrofluid at different points of time with respect to the initial step where ferrofluid is started to be poured down.What are your thoughts?

6. theEric

7. theEric

Oh! And maybe a free-flowing fluid's coefficients of friction are so low that friction is negligible on certain materials? I wouldn't know, and I don't know what assumptions are acceptable in this experiment. But I think some frequently used equations for fluids assume no friction. I would be only very minorly concerned with slowness due to the fluid flowing to the sides instead of straight down. In a small setup with simple measuring devices, I think it'd be negligible.

8. theEric

And orientation of a magnet or electromagent, in my opinion, should be whatever is easiest to calculate the force of the magnetic field on the fluid in different positions on the incline. Priority number two to consider when deciding on orientaion, in my opinion, is strongest flux possible down the incline, so the magnetic field's force is more affecting and thus more noticable and thus more measurable. With a bar magnet or solenoid, I believe your best option is pointing them down the ramp. For a ring, I think it would be best to look through the ring and .. picture time.|dw:1344579654170:dw| North and south can be changed. The three slanted lines are the inclines.|dw:1344580132867:dw|

9. theEric

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10. Jire

I can't thank enough for the help and thoughts you've given out so far! Now to get right into it I really liked the simpler option you suggested. I'm bad at coming up with simple solutions to difficult problems (that being finding a simple experiment that features _ferrofluids_ :D) but I find your idea has a lot of potential. On a note to just respond to what you had asked; I have studied a course of basic calculus so I know the primary stuff. Now then, for the time being I'd like to elaborate the details of the simpler option of an experiment you suggested. The experiment setup is this: A container with ferrofluid is placed on top of an object. We don't yet know the dimensions of this object but it will elevate the ferrofluid's position from the scale itself to such extent that the maximum magnetic force exerted from a magnetic field generator [positioned somewhere above all the other objects; the scale, the elevating object and the ferrofluid container) will minimally, if at all, distort the reading on the scale. If the setup would have to be extremely high for no effect at all to occur between the magnetic field generator and the scale, then in that case we will write down the error made to the scale reading and take it into account into the results. After having decided how much magnetic force is needed and from what distance from ferrofluid - and with how big intervals is the magnetic force changed - to lift enough of ferrofluid's weight for good results, these values for the magnetic force that we need to apply are tested to find the possible error the magnetic field generator would generate on the scale. At this point we have a setup in which the magnetic field force magnitudes generated for example for 5 intervals are enough to sufficiently lift the ferrofluid and cause minimal error so that the results will be scientifically valid. This is the rough summary. "A container would make sure that the magnetic attraction to a part of the fluid will affect the entire mass by exerting a force on the container." This I don't get though - the container will be non-magnetic so that force will not be exerted on the container right? : p But the rest seems to make sense "And you would calculate the magnets effect on the ferrofluid as a function of the container's apparent weight. If you have to be accurate and you can use calculus, that's the real benefit of a simply shaped container of ferrofluid." Can you elaborate how this works in practice with some example values? "Calculations using estimated shape of the fluid (or shape of the magnetic particle distribution) are easy with simple shapes. If the magnetic field generator can be accepted to be a distant source, then it will have different attractions to different parts of the container depending on distance. That will be calculated for your theory (the "expected" or "theoretical" results)." With a Gauss meter I can find how many Teslas are from different displacements from the magnetic field generator, but along with this how do I find and use function of container's apparent weight and field line distribution to find the theoretical total weight that the magnetic field would lift? Ps. I sent you my e-mail as private msg in case you think it's easier to communicate that way, or we can just go on talking here if you prefer : p