ChemMatters Infographic: Why Bacon Smells So Good

Why bacon smells so goodBacon and eggs. A bacon, lettuce, and tomato sandwich. Bacon crumbles sprinkled over roasted Brussels sprouts. Even a doughnut topped with maple icing and, you may have guessed, bacon. Hungry yet? These are all food items that have one time or another been on my menu. The common thread, of course, is the crispy, tasty addition of bacon. How does bacon go from its initial properties and appearance to the flavorful, delicious cooked product that many of us love to eat? Continue reading ChemMatters Infographic: Why Bacon Smells So Good”

Martian Gardening

Look at a raw potato and you might visualize tater tots. Potato chips. French fries. A baked potato dripping with butter. The Martian character Mark Watney looks at one and sees survival.

Readers of Andy Weir’s The Martian, including those who have joined the currently running American Chemical Society (ACS) ChemClub virtual book club, will recognize the humble potato as a key plot item. It’s a major part of Watney’s saga to survive until a possible rescue from his predicament of being left for dead on the planet Mars. He calculates that his remaining food will not provide him with enough calories to last until rescue. (Watney “spares you the math” in the book, but you can do the math yourself with the Think Like a Scientist: Back of the Envelope Calculations handout from the virtual book club resource packet.) His solution is to turn his living space into the first Martian garden, using raw potatoes sent with his mission team to use for a Thanksgiving meal as his planting material. The challenges are many.

What are the chances for actually growing food on Mars, beyond the science-based fiction of the book? A view of the planet’s dry red landscape might suggest the chances are slim. Dig deeper into the issue using additional free resources from ACS.

ChemMatters April 2017 coverChemMatters is a magazine designed for high school students to help find connections between chemistry and the world around them. The most recent issue includes the articles “Growing Green on the Red Planet” and “Open for Discussion: Surviving on Mars.” The two pieces discuss the extreme conditions astronauts would face on Mars. Although “Growing Green on the Red Planet” states that it is the most habitable planet in our solar system besides Earth, humans (and any plants) would face extremely cold temperatures, an atmosphere of 95% carbon dioxide, a lack of readily available water, and less than ideal soil. The article also touches on plant growth experiments done on Earth using volcanic soil from Hawaii to simulate Martian soil.

Readers can also take advantage of two accompanying resources for “Growing Green on the Red Planet”: a Teacher’s Guide and Background Information. The Teacher’s Guide is packed with tools you can use with the article itself and extensions to take the article topic further. You’ll find an anticipation guide, student questions and answers, possible student misconceptions, links to lesson plans on the science of soil and the chemistry of fertilizer, and more. I found the beginning of the Background Information particularly interesting. It summarizes the spacecraft that have been used to study Mars and the resulting data/information obtained by each. The first was in 1964, and a future mission is in the works.

The ChemMatters site also highlights the video “Can We Grow Plants on Mars?” from D News. At three-and-a-half minutes, it could be a good way to kick off a discussion of the chances of Martian gardening.

Together, these free resources are ways to link science fiction from The Martian with real-life connections to Mars and its possibilities.

The Smell of Rain

After a long, dry summer, a rainstorm is often welcomed. The first rain of the season always seems special, and a bit different, especially because they are often accompanied by a unique smell. You’ve probably smelled this type of rain before. It has an earthy and sharp, sweet smell that is unlike any other. And it doesn’t happen with the rainy days that follow. The smell is distinctive enough to have its own name, petrichor, pronounced, peˌtrīkr. The February issue of ChemMatters magazine has a wonderful infographic about petrichor that was developed by an ACS ChemClub member.

This term was coined bin 1964 by two Australian researchers, Isabel Joy Bear and Richard G. Thomas, for an article in the journal Nature. The term comes from the Greek word petra meaning stone, and ichor from Greek mythology, meaning the fluid that flows in the veins of the gods.

It may seem odd that rain would have a smell at all, because rain starts out as pure water, which has no smell. Bear and Thomas reasoned the smell must have something to do with what happens as the raindrops hit the ground. They duplicated this process in their lab by drying samples of clay earth and then subjecting it to varying amounts of moisture. By analyzing the compounds that cause the odor, researchers have identified the source of petrichor.

It turns out that during dry weather, soils collect volatile plant oils (such as terpenes and fatty acids) that are released into the air when the rain lands on them.

Another contributor is the compound named geosmin, which is formed by bacteria in the soil. The human nose is very sensitive to geosmin and can detect it in as little as five parts per million (ppm).

And finally, ozone (O3) and nitric oxide (NO) that occur naturally in the air contribute to the smell of rain, as they are absorbed by the rain as it falls.

It is interesting that in India the perfume industry in the region of Kannauj hasbeen making a perfume by distilling these same elements from the clay soils in the area. it is known asmitti attar orEarths perfume. It has the same smell as petrichor.

While the chemical nature of petrichor has been well understood for several decades, it wasn’t until 2015 that scientists understood the mechanism of how the odor was released into the air. Researchers from the Massachusetts Institute of Technology (MIT) used high speed cameras to film raindrops hitting the ground. They found that when the raindrops hit the ground they form create aerosols in air bubbles inside the drop, like gases in a glass of soda pop. These bubbles burst and escape into the air, making Earth’s own perfume.

This graphic is a winning entry in the inaugural ChemClubInfographic Contest. ACS ChemClubs were challenged to take a chemistry topic and turn it into an original informational graphic. Entries were judged on originality, and the ability to convey accurate science details clearly and creatively. This infographic was conceived by Michelle Prunier from Guilderland High School in Guilderland Center, NY. It appears in the February 2017 issue of ChemMatters.

 

A Measure of Confusion

Typical timber frame joints
Typical timber frame joints

We had a visitor from New Zealand stay with us this summer.  While he was here he took a course on building in the Timber Frame construction style.  This involved heavy beams, mortise and tenon joints and lots of measuring.   His biggest frustration was the measuring. As he is from a metric nation, he had a very hard time with our system using inches and feet.  He had a hard time imagining what a 1/16 of an inch was and if 3/8 inch was bigger or smaller than 7/16.  With some work, he was able to finish the work and they came out great.

Students in school will be facing a similar challenge, but perhaps in reverse, as they will once again be meeting the metric system in their science classes.  In some ways the U.S. Customary system of weights and measures is much worse than any other countries.  We are stuck with a Frankenstein’s monster of measurements that involves a mishmash of systems from many different sources. We buy gasoline by the gallon, but soda by the liter.  Athletes play football on a 100-yard field, but they run the 100 meter dash in track and field.  We measure in fractions of an inch, until things get very small and then we use decimal measures, such as thousandths of an inch.ChemMatters Cover - Dec. 2014

This is the topic of an article I wrote for the December 2014 issue of ChemMatters magazine. ChemMatters is an award-winning magazine for high school chemistry, which aims to explain how chemistry works in our everyday lives. Each issue includes a Teacher’s Guide containing background information, follow-up hands-on activities, classroom demonstrations, and other resources to facilitate student comprehension.

In my article “A Measure of Confusion” I follow some the issues surrounding our current system of measures, including the loss of a NASA spacecraft that crashed instead of landing on mars. This was due to an incorrect conversion from English to metric units.

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By the way, if you join the new American Association of Chemistry Teachers (AACT), you will receive a one-year subscription to ChemMatters as part of your membership.  And there is nothing confusion about that!