Re: I am doing a 3-d magnetic field viewing project but I need a variable.

Hi Lakotah!

This must be about the e and m field bottle project. If it were me, I would use the bottle as a measuring device (a scientific instrument), and then make the magnets and field patterns be your variables.

For example, does the viewer-bottle show you that the field of a strong magnet has a different shape than the field of a weak magnet? (You would have to find two magnets which are the same size and shape, but where one is much stronger.) Or, does the field from a "north" magnet pole have a different shape than the field from a "south" magnet pole? Or even mor interesting: how are the fields between two "north" magnet poles different than the fields between a "north" and a "south" pole? Your "variable" is the position of the magnet poles.

Or, you could compare the viewer-bottle with another method of showing the fields. Then, your variable is "method used to reveal fields". Magnetic fields can be drawn by placing the magnets on paper, then using a small compass to detect the field's direction, then drawing lines on the paper. Or you could get some iron filings (Edmund Sci sells them) and sprinkle them on the paper. Which method is best?

If you use your project to investigate a really interesting question, then often the variables will already be there, and you won't have to put them in by hand. In science, the rule is "Change only one thing at a time". If you change several things, and if you then see some interesting results, then you won't know what caused those results. For example, if you try magnets which have a different strength, but also have a different shape, you won't know if your results were caused by the different strengths. Maybe the different shapes are the important change, and the different strengths didn't make a difference in your results. This is called "The Control of Variables". You must "control" your experiment to keep more than one variable from changing at the same time.

Other ideas: in an electromagnet, does the viewer-bottle show a different field for AC versus DC? (You would have to figure out how to run your electromagnet with DC and with AC, and guarantee that the amperes of current were the same for both AC and DC.)

How sensitive is the viewer bottle? If you put a strong magnet on the table, how close does the bottle need to be before the iron fibers begin to align? Compare this distance with the distance that a compass must be from the same magnet. And, does it matter whether the magnet pole is aimed at the bottle, or is the field just as strong when the magnet is turned sideways? The direction of the magnet could be your variable.

Well-p, I hope I managed to answer your question, or at least gave you enough stuff so you can answer it yourself! :)