thedudeo Posted August 20, 2014 Report Share Posted August 20, 2014 So my IA involves making up saline solutions. I took 10.0mL of water and dissolved different amounts of salt grains into it, to make up different solutions, as it was my independent variable. The uncertainty for this is confusing me however. I originally was using salt concentration by weight as a percentage. What I mean by this is for example I added 0.025g of salt to 10.00mL of water, then labelled this as having 0.25% salt. I'm not sure if this is correct, and if it is, how to record the uncertainty associated with it. So I've been thinking, what if I recorded my independent variable as concentration instead of as a percentage. The concentration of salt would be 0.043 mol/L ±0.505 (in the aforementioned solution). I am worried that recording it as mol/L is too much chemistry for a biology internal assessment, so I am conflicted upon going through with this or with using the percentage weight, for which I am not sure of the uncertainty, or even if I need to include units. It'd be great if someone could offer advice of some kind, this is a bit of an issue and my biology teacher is clearly not comfortable with me bombarding her with questions. Thanks in advance! Reply Link to post Share on other sites More sharing options...
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