Properties of Matter
The Theme of Elements and the Periodic Table in Properties of Matter
Oxygen: The Good, the Bad, and the Art-y
We know that gaseous oxygen is essential for human life. We literally need oxygen to live. Without that simple little diatomic gas we would perish, and perish quickly. Did you ever wonder what else oxygen can do in its other forms? You know, the type of oxygen that's not a gas?
(Image from here.)
Oxygen makes up 21 percent of the Earth's atmosphere.3 Near the ground, almost all the oxygen exists as the diatomic oxygen gas O2. If we were to venture higher up in the atmosphere, we would find a very different form of oxygen.
Diatomic gaseous oxygen exists low in the atmosphere. (Image from here.)
High in the atmosphere, ultraviolet light from the Sun splits oxygen gas into atomic oxygen (O). The oxygen gas we know and love (and need) is chemically reactive. How reactive? Atomic oxygen is crazy reactive. It is so reactive that it can damage spacecraft and satellites in orbit.
Atomic oxygen is especially reactive with the element carbon. Carbon makes up stuff called soot. Bert from Mary Poppins knows all about that stuff, being a chimney sweep and all. When scientists from NASA treated a soot-damaged painting with atomic oxygen, the carbon in the soot reacted with oxygen to produce gases that simply floated away.4
You may be wondering, "Who cares if atomic oxygen reacts with soot?" Have you ever walked through a museum and witnessed a painting that took your breath away? Did you ever wonder how all of the masterpieces from artists long ago are restored and kept in such pristine condition?
Art is not meant to last forever. It can be easily damaged by mundane events such as people sneezing on it, touching it, or by smoke during an unfortunate fire. Maybe that last event isn't such a mundane one after all. The repair of damage to artwork is the job of art restorers. These folks are highly trained in their field because art repair is not an easy task. Most of the materials used to correct damage to art can actually further damage it in the process. Yikes.
So how does atomic oxygen help art restorers do their job? Since atomic oxygen reacts only with what it touches, imagine a painting that has a layer of soot damage on the surface. When the surface is treated with atomic oxygen the surface impurities and damage are removed by atomic oxygen but the paint layers below are left unaffected. This method is much less invasive than more conventional treatments which involve treating the painting with organic solvents to remove soot.
Check out a painting before and after restoration below.
The Expulsion of Adam and Eve from Eden. (Image from here.)
Sistine Chapel: Daniel. (Image from here.)
If you'd like to learn more about art restoration or how to become an art restorer, check out these links: