If iron is exposed to air, it begins to rust. What conclusion can you make about air, based on this observation?
http://en.wikipedia.org/wiki/Rust
Iron is exposed to air.what is the observation
Based on the observation that iron begins to rust when exposed to air, we can draw the conclusion that air contains oxygen. The process of rusting, also known as corrosion, occurs when iron reacts with oxygen in the presence of moisture.
To further confirm this conclusion, we can conduct a simple experiment to demonstrate that oxygen is indeed present in air. Here's how you can do it:
1. Fill a glass jar with water to about three-quarters full.
2. Take a small piece of iron, such as a nail, and thoroughly clean it with sandpaper to remove any existing rust.
3. Attach a string to the iron piece and tie the other end of the string to a stick or pencil.
4. Carefully lower the iron piece into the water in the jar, ensuring that it is fully submerged.
5. Seal the jar tightly and let it sit undisturbed for a few days.
After a few days, you will observe that the iron begins to develop reddish-brown rust, which is a clear indication that oxygen from the air dissolved in the water reacts with the iron. This experiment supports the conclusion that air contains oxygen, as the rusting process only occurs in the presence of oxygen.
Therefore, based on the observation of iron rusting when exposed to air, we can conclude that air contains oxygen.