3 See if you can think of a way to prove that it is the oxygen in air, not nitrogen, that causes rusting.

Get 3 glass vessels that are sealed except for the opening. If they are test tubes, get 2 rubber stoppers to fit two of the three. If they are clean, dry jelly jars with screw-on lids, then have two lids available for two of the three and use some stretchable plastic wrap to put over the mouth of the jars before affixing the caps (later). Get a piece of painted sheetmetal (iron) , or similar iron like nails that are not coated with zinc galvanization, nor plated with brass or nickel. Whatever they are, make sure they fit within the glass containers you choose, and are all the same size., and from the same sheet or batch of nails. Using some rough, 80-grit sandpaper, abrade the surface until the steel is bared of any paint or coating. throw one piece into the open trst tube ( or jar). In the second container put moisture-absorbing desiccant, place the stretchable wrap over the jar’s mouth then screw on the cap, or put metal, desiccant, then plug into the test tube. This will be the test for moisture significance. In the third test tube, place the metal in, insert a flaming wood splint or kitchen match until the fire goes out then withdraw the splint (match) and tightly plug it shut. If using the jar, place a small birthday-cake candle in it by lighting the candle, dripping the wax, and sticking the base of the candle to the hot wax at the inside jar’s bottom, until it sets upright. Then light it, place the metal in the jar in a place where the soot won’t contaminate the metal (off to one side) then with the candle burning, place a stretchable seal over the top and screw the lid on. The candle will consume a lot of the oxygen so this will be the test for lack of oxygen. The open container is the ‘control’ It is exposed to the daily oxygen and moisture content naturally occurring in your area. Keep the jars separated by a foot or so from each other so no one can say that it was magnetic effects or electric charge that was responsible for the rusting. Start your observation by logging each day, the progress of rusting. Try and quantify it by color, and percentage of area covered by rust, then perhaps apparent depth of rust penetration. You might be able to get desiccant at a pharmacy, or in a hardware store where people use it to remove excess humidity from closets

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