Which kind of nails rust faster in air or water? Give a brief answer

There is an experiment in junior high school: probably put nails into three test tubes, one of which is dry air (sealed). A test tube contains half a test tube of water, but leave some nails in the air. The third test tube is filled with water, flooded with nails, and then sealed with oil. In a few days, it will be found that only the nails in the second test tube are rusted. This experiment proves that rust must meet the requirements of both air and water. In other words, nails rust most easily in humid air. Note: The main component that works in the air is oxygen, and the main component of rust is iron oxide (reddish brown). Rust is a complex chemical reaction, and exothermic reaction is a slow oxidation phenomenon. The first question seems that the conditions you gave are not enough ... If the nail is immersed in water, it will rust slowly, but at least faster than air. Because there is only 0.03% water vapor in normal air, the solubility of oxygen in water is 0.03 1 (less than 1%), and there is no air in vacuum, so it will not rust. Take appropriate measures according to the rust of iron, such as painting iron products, tin plating or zinc plating (they will form a dense oxide film, thus isolating iron from contact with oxygen and water vapor). Or add nickel and chromium to make stainless steel to prevent iron products from rusting. The main component of the Martian atmosphere (about 95%) is carbon dioxide, including about 3% nitrogen and 1 ~ 2% argon, which add up to about 0. 1% carbon monoxide and oxygen, and a very small amount of ozone and hydrogen. The amount of water vapor is very small, which means that there is not enough water and oxygen on Mars, so it will rust slowly on Mars, but if there is no water on Mars (at least in junior high school) (because there is too little water, if there is too much water, humans can immigrate to Mars and electrolyze water to get oxygen), it is probably thought that nails will not rust on Mars.