Joseph Thiebes portland, ore. | science | art | food | politics

29Sep/170

Boiling : Sublimation :: Evaporation : Infralimation

Liquids become gases by two processes: evaporation, which happens at the surface only and occurs at any temperature as long as there is room in the atmosphere for the liquid to go; and boiling, which happens all over the volume of liquid at once and occurs only at the boiling temperature for the liquid at a given pressure.

Solids can become gases in these two ways as well. A block of CO2 (dry ice) or water ice will gradually evaporate, even at cold temperatures. This evaporative process in solids is called sublimation and occurs at the surface of the solid, almost like rock being weathered by the wind, but on a molecular scale.
This is why your ice cubes gradually get smaller if you leave them in the freezer long enough. The molecules of water are swept away in the microscopic movement of air molecules, and end up being deposited somewhere else in your freezer as frost.

In the case of CO2, if you heat it uniformly, it will reach a temperature at which it will become gas all at once, similar to the way liquids do when they boil. In solids, this is also called sublimation.

This ambiguity is a little bit of a problem, for reasons described in the excellent and captivating video below. The producer of the video suggests that there should be two terms to describe the two processes, and that one of the processes could be named after his YouTube channel. I agree that two terms would be a useful disambiguation.

I think "sublimation" is a good word for the solid analog of boiling. From sub (up to) + limen (limit), thus "up to the limit."

For the solid analog of evaporation at the surface, I suggest "infralimation," from infra (below) + limen, thus "below the limit."

15May/160

Green Chemistry seminar videos

Green Chemistry

Join the Portland, Oregon section of the American Chemical Society for a couple of wonderful talks on Green Chemistry.

First, Dr. David Stuart, Assistant Professor of Chemistry at Portland State University, offers a brief introduction to Green Chemistry and an example from his lab.

Next, Dr. Tom Wilson, retired Director of Materials Technology at Nike, offers an interesting look at the Green Chemistry of rubber in a story about zinc oxide in Nike's Environmentally Preferred Rubber.

Take a look at the two videos below!

This activity was supported by an ACS Sustainability Grant awarded to the Portland Section of the American Chemical Society. Videos recorded by Joseph Thiebes.

16Apr/160

Portland ACS Interview

Joseph Thiebes in the lab
Joseph Thiebes at NASA Glenn Research Center

Joseph Thiebes at NASA Glenn Research Center

The Portland section of the American Chemical Society interviewed me recently about my internship at NASA Glenn Research Center in Cleveland, Ohio in summer, 2015, where I worked on lithium-sulfur battery research:

Portland State chemistry student Joseph Thiebes loves materials science and explored battery technology during NASA internship

29Jul/150

Diamond Lattice Structure Pendant

The diamond lattice structure pendant by Joseph Thiebes, 2015.

Diamonds are a scam! They are very common, and rather worthless. One company has cornered the market, controlling how many diamonds are mined and how they reach the consumer. Mining for diamonds is back-breaking work, and the wages are ridiculously low.

Want to know more? Check out the video, and the beautiful jewelry from Iturraldediamonds.com, below:

Diamonds are a scam, and it is for this reason I have created the diamond lattice structure pendant. This pendant features the structure of diamonds, formed by carbon atoms in a specific arrangement.

Pick from a variety of materials, including everything from solid gold to white plastic and best survival knife. Shown below is the default material, blackened steel, giving the traditional appearance of carbon atom models.

The diamond lattice structure pendant by Joseph Thiebes, 2015.

The diamond lattice structure pendant by Joseph Thiebes, 2015.

The piece is about 1.5 inches across. Just loop your favorite chain through the open lattice and put it on. Science jewelry!

2Jun/150

Nobel Prize Laureate Eric Betzig

Eric Betzig, illustration by Joseph Thiebes

“I would never call myself a chemist,” said Nobel Prize in Chemistry 2014 recipient Eric Betzig.

Betzig was this year’s speaker at the annual Mark Gurevitch Memorial Lecture Series, hosted by the Physics Department at Portland State. During his lecture at Hoffman Hall on May 14, Betzig spoke about his career and his prize-winning work. Read more about Betzig's talk in this article by Joseph Thiebes, and in the video below.