Hey there, I am studying the effect of current on the strength of an electromagnet for my GCSE assessed practial. I set up the experiment with an iron c-core on a set of scales, and a electromagnet above, in theory, I should be able to see the weight of the c-core go down as it gets lifted off the scales. I varied the current using a variable resistor. My results are very slight at first, then they speed up (the graph is not very steep, then gets steeper).Could this be because at first the c-core is nearer the outside of the magnetic field induced by the electromagnet, so therefore the magnetic force pulling upon it is weaker, and as it gets closer the magnetic field gets stronger, and so pulls the c-core up more? Also, My teacher tells me that I am measuring the mass, and I need to link this to the weight. I have never really got my head round the whole mass/weight thing. How do I do this? I am very unclear about the two of the above, Any help very much appreciated. I wrote what I could in my 1st draft (I would put it on here if I knew how), and then gave it to my teacher, and these are the main points that he told me work on.