|MadSci Network: Chemistry|
I think we can say you are both correct. Your teacher has a good point though. There may be a few things in certain foods that will leave the translucent spot on the bag but they are not lipid. So to be more certain that the spot was made by lipid you need to see if the spot disappears when you use a solvent that dissolves the lipid. You must use a mixture of orgainc solvents to do this. When scientists do experiments, they try to confirm that what they found. they do this several ways. First, they always repeat the experiment several times to be sure they get the same answer. They also try to do something else to confirm what they found. Your teacher has given you a way of confirming that what you found was actually lipid. If it leaves a mark on the bag it might be lipid. If t the mark dissolves in a solvent that dissolves lipid, you can be even more confident that what it was lipid that made the mark in the first place. By the way, I have used the term lipid and not fat. Lipid is composed mainly of two types of compounds, fat and oil. Fat is solid lipid and oil is liquid lipid. Butter is a fat and corn oil is an oil. Both are lipids. I can say very truthfully that corn oil is 100% fat free. Using the word fat when you mean lipid is like saying apple when you mean fruit. Hope this helps Good Luck
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