Study Guide

Properties of Matter Themes

  • Elements and the Periodic Table

    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:

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  • Biology Meets Chemistry

    Global warming: Melting Icecaps/Icebergs

    Melting is the process of a solid becoming a liquid. Who would have thought such a simple physical change would have such huge environmental implications? We're not talking about melting cheese for a grilled cheese sandwich or melting chocolate for that fountain we bought on a late night infomercial. We're talking about melting on a much larger scale. We're talking about the melting of the polar icecaps.


    Iceberg, right ahead. (Image from here.)

    The polar ice caps are located in the high latitude region of the Earth like the North Pole, the Arctic, or similar types of places. They're basically a solid landmass covered by ice. Icebergs can be big or small and are found in a multitude of shapes. They key is in the ice.

    All of the Earth's ice caps are formed from water alone. This is different from the ice caps on Mars. They're made of both water and carbon dioxide.5 Ice caps on both planets form due to their high elevations and lack of solar radiation: perfect conditions for ice formation. Sadly, Earth's ice caps have transformed over the last 12000 years. Our favorite frozen geoforms are melting.


    I'm melting. (Image from here.)

    Why are the ice caps melting? We can thank the good 'ole phenomenon of climate change. In a nutshell, the Earth is warming in part due to the increased release of methane gas, which is released from factories and automobiles. This is a warming gas.

    Certain areas in Greenland and Antarctica are still abundant with ice caps due to increased snowfall, but icecaps are melting at an alarming rate overall. Most global warming experts say that during the latter part of the twenty-first century, the melting will speed up due to the greenhouse effect. The melting ice fills our oceans with liquid water at a high rate, which could cause tropical storms, flooding, and hurricanes during storm seasons, especially in coastal regions.


    Hurricanes are a major concern after ice caps melt. (Image from here.)

    It has been reported that the ice caps are melting so fast that the world's oceans are rising more than twice as fast as they were in the 1970s.6 Most experts believe this melting effect is also due in part to thermal water expansion.7 Studies have shown that the Thames River in London could rise by eight to thirty-five inches in just a few years. What this all means is we have to accommodate a lot more water and quickly. This is not necessarily an easy task.

    All of this melting is thought to be directly related to humans and greenhouse gases. Things like carbon dioxide, nitrous oxide, and methane gas are all contributing factors. The ocean is slowly warmed as a consequence. This warmer water flows underneath the ice shelves and begins to melt the ice caps from the bottom while the warmer air begins to warm the ice cap from the top.

    The big question is: What can we do to prevent the ice caps from melting? There is no simple answer because it's a complicated situation at the center of a maze of political, economic, and social issues.

    You can learn more about the melting polar ice caps here.