Wednesday, December 19, 2012

The obesity epidemic..... focus of a 14-page special report in The Economist


 


Michelle Obama decided to focus on this during her husband's first term in office. Commercials on TV flash "healthy" snacks, exercise programs (P90X anyone?) and diet plans. McDonalds started posting calorie information for its food, before even the requirements of Obamacare make it legally necessary.  And now The Economist provides us with a 14-page special report about something that expands so far beyond America it really is a world-wide epidemic. What is this problem? It is obesity.

Two-thirds of Americans are overweight- this means with a BMI over 25. As imperfect as the BMI measurement is, it is currently the accepted measure of whether or not someone is considered ideal weight, overweight or obese. But the problem is not just American; it spans Europe, the Pacific Islands and even China. It seems to be a worldwide trend that the girth of all continues to expand. And sometimes the methods we choose to combat the problem are simply outward motions to mask the real priorities and economic advantages of promoting a lifestyle and diet that perpetuate the problem.

Our natural hormonal impulses controlling hunger worked in the ancient cavemen societies. People basically ate until no more food was available. This was a good thing because nobody knew exactly when the next big meal might be available. However, in an age of super-size me drinks, fast-food on-the-run, and endless fatty, sugary snacks around every corner, traditional hunger control methods don't seem as effective. Our leptin (fullness hormone), and rhelin levels (hunger signals) have been rewired to fight against weight loss. Because once the body gains weight, our hormone levels are actually conditioned to maintain that weight.

This affects poorer people more than the wealthy who have access to more expensive foods, fancier gyms, and other resources for maintaining health and weight. For the less affluent, readily available and cheap junk food adds calories on top of an otherwise high-stress, low income, lesser educated lifestyle. For these reasons, poor people develop obesity in much higher numbers than their rich colleagues.

Many efforts to treat obesity medically have failed. Numerous medications have circulated through the market and failed, including the infamous Fen-Phen made by Wyeth in the 90s. Effective medications seem to have side effects that outweigh (pun intended) the benefits of the drug. Whether its heart problems, gastrointestinal issues, or the central nervous system acting up, the ideal drug is yet to be discovered and developed. And on top of it all is the cost to the consumer. Most of the drugs are prohibitively expensive- without a foolproof guarantee of success. The consumer still has to follow a regimen of diet and exercise- which circles back to the original problem that caused obesity in the first place- an inability to balance, control and maintain a healthy balance of exercise, diet and proper lifestyle.  Of course bariatric surgery is always an option for the grossly obese. As stated in The Economist, Edward Livingston, bariatric surgeon and an editor at JAMA thinks the surgery needs more research before being expanded to the general population.

The heart of the problem seems to be tied to a conflict about what kind of food people really want to eat. Unhealthy foods bring in the most profits for food companies, yet none of them want to be touted as the culprit of the obesity epidemic. Who can blame them for selling products that make money? In the past decade, the sale of packaged food jumped 92% and sale of soft drinks doubled. Disturbing? I think it is more puzzling as the same people consuming these foods also crave diets and access to health foods.
Yum! Brands' chief nutrition officer said, "Consumers say they want to eat healthy, but their behavior tends to be slightly different."

This leads into a discussion of public policy about food and how to properly regulate, or not regulate people's intake of different foods. Is taxing soda the answer? New York tried this and it failed miserably.One other approach would be to limit the size of a soft drink available for purchase. The "nudge" approach seems to be the technique of choice for politicians. They want to make the healthier alternative more attractive and easier than the unhealthy choice. One way to do this is to make exercise easier- improve access for pedestrians to encourage walking. Require calories be provided on public menus, modify menus in school cafeterias, and find other policies that gently guide residents to make the right food choices. Until it becomes clearer what the truly effective changes are, the small nudges are the approach of choice for lawmakers.

Until we have more information about how to successfully motivate people to change their lifestyles and backing from both pharmaceutical and food companies to support these changes, this problem will remain complex. The possibilities are endless for solutions- now the question is just HOW?

Wednesday, December 05, 2012

Solutions and Basic Chemistry

As I prepared my lectures on solutions and then about acids and bases I decided a post about solutions would be in the same vein as a post about salts in basic chemistry. Both are everyday words that many people use in the kitchen and when preparing basic cold/flu remedies. In the kitchen, we refer to salt exclusively as table salt or NaCl. In chemistry, anything that makes ions in solution is a salt. It is such a basic term in science that the first classification system of the discipline was based on the term.

"Salts played a pivotal role in the historical development of chemistry as a discipline. The medieval alchemist Paracelsus named salt as a third principle of nature. However, he treated it more as a category of nature and his work became known throughout Europe in the middle of the 1700s. As the chemical behavior of salts became better understood, there was a significant increase in the number of salts known and this resulted in a need for a classification system. Classification as a method of understanding became a defining characteristic of science in general and of chemistry as a discipline."

Solutions are similar to salts in that the chemical meaning of the term spreads far wider than simply the kitchen or medical application. In the kitchen we prepare cornstarch solutions to thicken our gravy. We prepare saltwater solutions to cleanse our throats when we have a cold. A baking soda solution might be used as a basic household cleaner. Around the house, a solution seems to be primarily a small amount of a solid dissolved in at least enough liquid to make all of it go into solution.

In chemistry it is far, far more than that. A solution is basically anything that makes up a homogeneous mixture or a mixture of uniform composition. In class I clarify this to say that if you can't see the constituent components of the mixture, it can be classified as homogeneous. Then I joke that this would mean I would have to clarify what type of mixture I was referring to, for example, if I said "air." The choice would be Los Angeles air (heterogeous and not a solution) or desert island air (homogeneous mixture = solution). I'm just pointing out that if particles can be seen in the air, it cannot be considered a solution.

Up until the last paragraph of this entry, a beginning student might still assume that a homogeneous mixture would have to be a solid dissolved in a liquid. This is not true from a chemical standpoint. A homogeneous mixture can be a solid dissolved in a liquid (saltwater solution), liquid dissolved in a liquid (ethanol in water), a gas dissolved in a liquid (carbonated beverage), a liquid dissolved in a gas (water vapor), or a solid dissolved in another solid (alloy of metal like brass). Basically, any phase intermixed with any other phase of matter can qualify as a solution.

Sometimes you may not be able to tell a solution from a pure substance (element or compound). The best way to know if you have a solution as opposed to something pure would be to have it undergo some kind of physical change. In many cases, simply heating it up to melting point/boiling point will separate the two pure substances by the difference in their melting points/boiling points.

When I get into acid/base chemistry, suddenly the students must add the acid/base neutralization concept to their understanding of concentration and volume. Although they have seen this before in the chapter on chemical reactions, many of them do not remember that the neutralization of an acid/base gives a salt and water as products.  They must get comfortable interconverting between concentration, volume and moles. They must know the molar ratio of the acid to base that they are working with in their reaction. Then, they must be able to perform a titration to neutralize all of an acid and correctly determine the concentration of it based on a known concentration of base.

Solutions are a challenging part of introductory chemistry. And one that stretches people beyond their basic kitchen comprehension.

Wednesday, November 21, 2012

Happiness Quotation.....


 

“One does not play Bach without having done scales. But neither does one play a scale merely for the sake of the scale.”
-Simone Weil

Friday, November 16, 2012

Baking Soda Lab

This is a conceptual drawing of the baking soda lab. I love this lab because it asks the students to really think about the concept of molar quantities. In Part A they measure out an amount of baking soda (NaHCO3) [I can't seem to make subscripts in Blogger]. Then, they convert to product using molar ratios/molar masses.  Measuring the exact mass lost in the reaction is irrelevant in this case, because they can measure the pure starting material and convert directly to moles (with molar mass).

In Part B they are unable to measure starting material and convert to moles because the starting material is contaminated with an impurity. The impurity is heat-resistant and unaffected in the experiment. In this section, they must use the law of conservation of mass to figure out how much H2CO3 was lost in the reaction. It is only by subtracting the mass of the (product + test tube) from the mass of (starting material + test tube) that they can find the mass of the H2CO3 produced in the reaction. (H2CO3 is unstable and dissipates as H2O and CO2). From the mass lost, they can find moles of carbonic acid (with molar mass) and then use molar ratios to find the mass of baking soda in the original material. They are asked to calculate percent composition of the mixture. From their original mass they have the denominator of their equation. The pure material is found with the mass of carbonic acid and molar ratios. They divide pure baking soda by the impure mixture and multiply by 100 to get their percentage.

From my perspective this seems to be a straightforward lab. But- if you aren't used to using balanced equations and molar ratios it is a challenge to visualize it. Hopefully this picture helps students understand what is going on in the experiment.

Sunday, November 11, 2012

#Foodchem Carnival: I am most thankful for table salt this Thanksgiving









Last year when I was at home with my young infant daughter during the holidays I watched Lucinda Scala Quinn (on the TV show Mad Hungry) cure a salmon. A properly cured salmon does not need to be cooked because the brine mixture removes any dangerous substances.

This brought back memories of my visit to the Dead Sea Scrolls exhibit in Seattle a few years back. I'm fascinated that the high salt content of the Dead Sea created a sterile environment in which the ancient texts of the Old Testament were discovered. The same chemical that cures a salmon for my dinner created a  preservative in which historical documents survived for a record amount of time.

Initially, neither the salmon nor the Dead Sea Scrolls exhibit seemed all that relevant to my chemistry teaching career. While one is delicious to eat and the other a seeming wonder of the world, the two seemed unconnected to each other and to my academic major .

Except that they both involve preparation and preservation with salt.  And in the nitty gritty of it all, this is really exciting.

What people do not realize is that the word "salt" is a completely different word in science than it is in the kitchen. In the kitchen "salt" is sodium chloride only. You can say "salt" in cooking and everybody knows exactly what you are talking about.  In science, the word "salt" encompasses any compound that contains an ionically bonded species, whether it be a metal/nonmetal combination or some other variety of cation/anion combination. Any neutralization reaction between an acid and a hydroxide base yields some kind of salt (plus water). The word salt is such a general term in science that, by itself, just refers to something that forms ions in solution.

Salts played a pivotal role in the historical development of chemistry as a discipline. The medieval alchemist Paracelsus named salt as a third principle of nature. However, he treated it more as a category of nature and his work became known throughout Europe in the middle of the 1700s. As the chemical behavior of salts became better understood, there was a significant increase in the number of salts known and this resulted in a need for a classification system.  Classification as a method of understanding became a defining characteristic of science in general and of chemistry as a discipline.

Although salts historically include the many, many compounds of the first classification scheme in chemistry, we are exclusively referring to NaCl in the kitchen.

In food preservation and flavoring, salt (NaCl) is used to create a diffusion of water from a lower salt concentration to a higher salt concentration. When this happens we say osmosis occurs. This brings me back to previous posts about polarity, shape and solubility. What is it about salt that causes this to occur? It is ionic bonding.

In solid state, the salt is in recognizable form as a salt crystal. We see these all the time when we pour salt on our food.  In water, salt crystals dissolve to form ions in solution. After salt has dissolved it looks just like pure water- it just has sodium (Na+) and chloride (Cl-) ions dissolved in it.  A pure covalent or polar covalent compound does not separate like this in a solvent. Often my students draw the water molecule as ions in solution (H+ and OH-) along with the sodium and chloride ions. However, this is incorrect as only ionic compounds separate into ions in solution. It is the ions (Na+ and Cl-) dissolved  in water that create a high concentration of salt. A high concentration of sodium and chloride ions in water creates a driving force for liquid to flow in one direction: from lower solute concentration to higher solute concentrations thus drawing water out of bacteria cells and causing them to die.

One common misconception about salt preservation is that salty foods around the house are more likely to be free of bacteria. This is false based on the percentage salt needed to create this effect. The food must be at least 10% salt to kill bacteria (possibly closer to 20%). Most salty foods do not have more than one or two percent salt.

As far as salt's mechanism for flavoring, the salt loosens the tight protein coils so that more water is trapped in the fiber of the meat/fish. This makes the fish juicier.  

All of this inspires me to use my newly purchased turkey brine from Williams Sonoma to enhance the Thanksgiving Day meal at our house. Although I will not be adding enough salt to remove all bacteria from my poultry (and thus I will cook it), I will allow more water to penetrate the meat making it juicier and a more delectable meal for all. 

And I will have new anecdotal and historical information to share with my holiday guests about salt preservation and flavoring. Salt not only played a critical role in defining science as a discipline separate from philosophy or religion but it preserved historical documents (Dead Sea Scrolls), and flavors our everyday meals. I am most thankful for salt this holiday season.
 
Figure: Sodium chloride crystal structure next to sodium and chloride ions surrounded by water molecules (as if in solution) 
 
Diffusion

Tuesday, November 06, 2012

Shape and Polarity

Because I don't want all of my images to be taken from one copyrighted source here on this blog I decided to surf the web for good images of 3-dimensional molecules with polar bonds. I have made my own very clear handout from one particular textbook that I would like to post on this blog but for copyright reasons I will not.

A difficult concept for my students is the determination of polarity based on the difference of electronegativity of individual bonds in a molecule. Out of the four textbooks I've used for this topic in class, only one of them really includes illustrations, diagrams and tables that are effective in conveying this topic with any kind of logic.

Because students have trouble building the models of the molecules, naturally it is hard for them to imagine the dipole moments created by individual bonds within the molecule. These dipole moments are directional and have magnitude. Therefore, in the case of a symmetrical molecule, these directional dipole moments cancel each other out and you actually get a nonpolar molecule.

Examples listed below:



                                           
 (PCl3O)This is a picture of an electron geometry of tetrahedral (four groups surrounding central atom) that also has a molecular shape of a tetrahedral. In many cases this shape is perfectly symmetrical and the individual dipole moments cancel each other out. In this case, the molecule is not symmetrical because the atoms surrounding the phosphorus have different electronegativity values.  As noted, the net dipole moment is pointing toward the oxygen atom and the molecule is considered polar.





                                                           


(BF3) Boron trifluoride is an example of a trigonal planar electronic geometry that also has trigonal planar molecular shape (3 groups surrounding central atom with 0 lone pairs). In this case, all atoms surrounding the central atom have the same electronegativity values (same atom) and therefore the individual dipole moments of each bond are the same. If we added the sum of the vectors the sum would be zero. Therefore, the molecule has no overall dipole moment and is considered a nonpolar molecule.



0917



(NH3) This ammonia molecule is a perfect example of the tetrahedral electron geometry with the trigonal pyramid             molecular shape. Because of the lone pair of electrons on the nitrogen, the vectors pointing from the hydrogen to the nitrogen sum to be a net dipole moment pointing straight up through the molecule. As noted, the net dipole is 1.47 D with the magnitude shown. This is not a symmetrical molecule and in most cases exhibits an overall dipole moment.
**An exception to the rule that a tetrahedral/pyramid is polar would be PH3. While it has the same shape as NH3 it is a nonpolar molecule. The reason is that there is no difference in electronegativity between phosphorus and hydrogen (calculated difference). Therefore, the asymmetry of the molecule does not matter- there is no dipole.

**02/2013: I received an email from a reader stating that there is a dipole moment associated with PH3. Although there is no difference in electronegativity between the phosphorus and hydrogen, the lone pair of electrons on the pyramid creates an uneven distribution of electron charge.




The water (H2O) molecule to the left is a tetrahedral electron geometry (4 group surrounding central atom) with a bent shape. The two lone pairs are not shown in this drawing. The four total groups (2 bonding and 2 lone pairs) assume the usual tetrahedral structure, however visually only two atoms jut out from the central atom. This creates the bent shape.  The dipole moment of this molecule is similar to that of NH3 in that it points straight up through the molecule. If you add the vectors of a dipole pointing toward the oxygen from each hydrogen, you get a straight line through the center.


The four tetrahedral molecules to the left (variations of methyl/chlorine molecules) exhibit the change of a dipole depending on how many electronegative substituents are attached to the central atom. With one chlorine (far left) the dipole moment    points in the direction of the one polar bond. For two chlorines, the overall dipole points halfway in between the vectors. On the far right, notice that the dipole is 0D. This means that when carbon has four chlorines surrounding it in a tetrahedral arrangement, the individual dipole moments cancel out and the molecule has no polarity. Carbon tetrachloride is an example of a tetrahedral molecule that has polar bonds but no overall dipole moment or polarity.

Sunday, October 28, 2012

Balloon representations of VSEPR shapes



It seems to be very hard for students to initially picture the VSEPR shapes of molecules. They draw the Lewis dot structures and then get really hung up on trying to visualize how the Lewis doc structures correlate to the VSEPR shapes.

Here is my visual aid. BALLOONS!
It really is the best way to picture it- it is better than a model kit and better than trying to draw it three-dimensionally.
The two green balloons represent a linear molecule spread at 180 degrees. Typically without steric hindrance any two atom molecule will be a straight line like these two balloons.
The next two drawings represent the most mistaken structures. The trigonal planar (three balloons) and the tetrahedral (four balloons) are actually very, very different shapes. The trig planar is two-dimensional (flat) while the tetrahedral is three-dimensional. This is tricky because if one of the balloons in the tetrahedral is a lone pair of electrons (empty cloud without an atom) the structure becomes a trigonal pyramid. This is NOT the same thing as a trigonal planar molecule. It is still three-dimensional- it just has an empty space where one of the clouds previously had an atom.

I don't include the trigonal bipyramid and the octahedral in my class but those two structures are included just to get a preview of what people study at the next level of chemistry.

Build these structures to fully understand VSEPR! Don't mix up your trigonal pyramid with your trigonal planar molecules!













Thursday, October 25, 2012

Spiderman, Regenerative medicine, the 2012 Nobel Prize and the future....



http://library.creativecow.net/articles/kaufman_debra/The-Amazing-Spiderman/assets/Lizard-man-afterserum.jpg(Dr. Curtis Connors from the movie Spiderman)

The most recently released version of Spiderman shows a mad scientist obsessed with his own ability to transform himself into a lizard. It all starts as part of a science experiment gone wrong- he's using an injection from his lab to try to grow back an arm that has been chopped off. In the process of just trying to regrow his arm, he ends up transforming himself into a completely different creature. This is just one example of synthetic biology that shows up in our lives. In this case it is purely fictional in nature. It may not always be that way.

This year the 2012 Nobel Prize for medicine went to two men (Sir John Gurdon and Shinya Yamanaka) for a discovery about stem cells that could bring this surreal, onscreen entertainment into reality. Both men contributed to the effort to manipulate stem cells in the body. Certain stem cells are blanks in that they don't start out with the same function for which they end up. If researchers manipulate them correctly, it is possible they could clone an entire human being. It also opens the door for the science fiction lizard of Spiderman to become a reality- this technology would allow cells of any variety (or organ) to be grown from a small sample of other cells.

In an essay for the Wall Street Journal last weekend, George M Church and Ed Regis write about larger applications of this technology in synthetic biology. Regenerative medicine just scratches the surface of what we are able to manipulate with genes.

"It is now routine to genetically reprogram microbes to make plastics, biofuels, vaccines and antibiotics. They have been engineered to detect arsenic levels in drinking water, destroy cancer cells and store digital data in DNA, making bacteria into biological flash drives."

And apparently resurrecting life from the dead is also a claim of synthetic biology:

"As for resurrecting extinct animals, this has already been done. In 2003, in Spain, a tree fell on a 13-year-old female goat named Celia, killing her. She was the last living Pyrenean ibex, a subspecies of wild mountain goat, which thereupon became extinct. A few years earlier, fortunately, a Spanish biologist had taken skin scrapings from Celia's ears and stored them in liquid nitrogen in order to preserve the ibex's genetic line. He and his team removed the nucleus from one of these ear cells, transferred it into an egg cell of a domestic goat and implanted it into the uterus of a surrogate mother, who gave birth to a live Pyrenean ibex."

Another potential application is to kill the replication method of viruses and render them ineffective.

"If you change the genetic code of the host cell, as well as that of the cellular machinery that reads and expresses the viral genome, then the virus could no longer replicate."


Regenerative medicine and synthetic biology seem to pervade the news these days with surprising abundance. Is this a sign that the field is on the verge of real discovery or is this just more hype on a trendy path of science fiction? Only time will tell.
http://decor4u.com/images/D/spiderman-detail.jpg

Sunday, October 21, 2012

#ChemCoach: Adventures in Working.....



In honor of National Chemistry Week I am participating in #ChemCoach hosted by See Arr Oh of Just Like Cooking blog. I am supposed to write a  summary about my current job.

Your current job.

What you do in a standard "work day."

What kind of schooling / training / experience helped you get there?

How does chemistry inform your work?

Finally, a unique, interesting, or funny anecdote about your career*


I am, by title, an Associate Faculty member of various junior colleges in southern California. This means that I teach chemistry classes at various schools based on the needs of the school at any given time. This also means that it is very easy for me to come in and out of the field on a semester-by-semester basis. In June 2011 my first child was born and I decided not to take any classes for the fall 2011/spring 2012 year. Then, in fall of 2012 I committed to teaching one class.

On the days that I teach I get up at 5 am to drive up to Orange County. Initially, the drive up there was horrifying to me- I had never done it regularly aside from a yearly trip up to Disneyland or Universal Studios. However, when I leave my house at 6 am there is absolutely no traffic. None whatsoever. I can relax in my car, pop in a CD and have an enjoyable drive up north. (On the flip end, I get off work at around 11 am and drive home. The traffic is very minimal at this time of day.)

Usually I arrive at work about forty-five minutes early. This gives me enough time to take care of loose ends: visit someone on campus for business, prepare my white board for class, boot up my computer,  make sure I have a waste container and all proper equipment if it is a lab day. Then, class starts. Students arrive by 8 am and sign my sign-in sheet. They turn in their labs from the previous week and we settle in for the daily "lecture." (For lack of a better term it is still called a lecture- I wish it wasn't.)

We take a break at 9:30 am or so and by the end of class we do the "clicker" slides. These are slides that allow the students to select an a,b,c,d answer for a question pertaining to the lecture. It gives students a chance to participate and it gives me feedback about what they understood and what they missed from the  lesson.

Then, at around 11 am we finish class and everybody goes home. My duties outside class include grading labs/quizzes/exams, answering student questions via email, maintaining my blackboard site and providing keys for all quizzes, tests and other assignments. (All of these are posted on my blackboard site.)

My job requires at least a master's degree in chemistry. Many people with a PhD also do this work but the PhD is not required.

Something unique about my career? I was hired as a chemistry instructor at a junior college as the result of a flute performance I did at a church in La Mesa. It was the most unusual way I've ever been hired in my life. An usher approached me at the end of the performance and asked me about my day job. He was a professor/instructor at a local college. The rest is history.

Tuesday, October 16, 2012

"You’re really going to make my son spend a whole year in a subject he will never use so that he can prepare to suffer at a boring job some day? "



The title of this article was copied from a post on a blog of The Washington Post. This particular statement provoked some strong feelings I've developed about basic science education.

We must require basic science literacy of our K-12 students. If we do not, we are not preparing our students to think critically, make informed decisions and harvest all of the pleasure and reward of an adult life. Learning science is about so much more than preparing for a specific job after college or vocational school. It is about seeing how science applies to everyday life and using that knowledge to improve everyday life.

Does anybody know when they are a sophomore in high school what their major will be in college? Maybe a few of us do, but most of us don't. Most American high schools are already deficient in preparing high school students to major in science in college (let alone chemistry which is more difficult than some other science majors).  How can we expect our students to choose a science major at all if we don't require (at least) an exposure to it at the high school level?

A response to this question might be the following: "Shouldn't the kids be able to choose what science they take at the high school level?" My answer is no. An exposure to science includes the building blocks of all types of science; at this point most fields of science are fairly interdependent. It requires a basic understanding of one field to gain a basic understanding of another field. They must have one year of chemistry, one year of physics, one year of biology and a year of freshman science (or something similar). If they take just this much science, it is my opinion that they are not really well enough prepared to major in science at college. To be successful at an undergraduate level in science (especially chemistry) you need to take two years of chemistry, two years of physics, two years of biology plus any freshman science requirement the schools provide. (Some schools have a freshman science class that is a hybrid of science types.)

Based on my assessment of what an adequately prepared freshman would have to take to be prepared for college, one year of high school chemistry is nothing. Nothing at all. It is a bare-bones exposure with a minimum of information. And here is what that year of chemistry will sow in a child's mind:

1. A knowledge of basic elements: what is dangerous, what is benign, what chemical under their kitchen sink must absolutely be removed when babies are born. (namely sodium hypochlorite)

2. An appreciation of where we've come since the advent of quantum mechanics. All of the gadgets, electronic devices and common household items we all take for granted are a result of the quantum mechanics revolution. The digital world has changed the way we function in an absolute way.

3.  A basic understanding of energy: What are energy sources and how does chemistry influence energy sources? How do humans interfere with this process? How is nuclear energy important and what is the basic chemistry of nuclear energy. With the price of gas rising, I'm sure we all agree that international energy resources are critical to the functioning of our nation. Everybody should understand these resources from a chemical perspective.

4. A fundamental understanding of how chemicals affect the human body. Our body is made naturally of chemicals. Sodium/potassium channels, water (H2O) and many other chemicals allow basic processes to allow us to live and breathe each day. How do the chemicals we add from outside our bodies interact with natural human chemicals on a daily basis?  My own grandmother never took chemistry and it was very obvious when she spoke about the drugs she was taking. She had no fundamental understanding of chemical processes in the human body.

On top of all of this- is it really fair to pigeonhole a child into a nonscientific career at such an early age? This is what you are doing by default if you do not require them to take chemistry. Science knowledge builds like a pyramid. Without basic chemistry, a child could never take biology or any of the other classes that apply basic chemistry. (This is why people like me never suffer unemployment- since everybody must take basic chemistry for their major there is never a shortage of basic chemistry courses to teach.)

Kids need science. Our world needs science. Way beyond any career decisions we make later in life - we all need to attain a basic level of science literacy.

Yes, all high school kids should be required to take one year of chemistry. At the very least.

Sunday, October 14, 2012

Chem 13 News- September Edition


Chem13 News Logo

I just received my copy of the September edition of Chem 13 News from the University of Waterloo in Canada. They had contacted me about using an article from my blog in their newsletter and I agreed it would be ok.

Because I was expecting a church-newsletter style publication, I was shocked when I received a professionally collated and printed version of this newsletter. It looks more like a journal than a newsletter. On the inside cover, there is an article explaining the magnesium oxide lab. The article states that the lab is notoriously problematic- mostly because of the side product magnesium nitride that also forms in the combustion of magnesium metal. (I thought the water addition step eliminated this problem.) Apparently reusing the crucibles is a source of error. Crucibles were designed to be only used once. Most labs can't afford to replace the crucibles after every experiment (let alone after every year). This introduces error as well.

Seemed very fitting that I should receive this immediately after posting about the magnesium oxide empirical formula lab.

Providence or luck?

Friday, October 05, 2012

Frustration over the Empirical Formula Lab

Why is it that every year we do this experiment and every year people get ratios that don't make sense? I thought that if you put the lid on your crucible right after the magnesium sparked (and starts to smoke) that you wouldn't lose material. This would result in accurate calculations for the ratio of magnesium to oxygen in magnesium oxide.

Right? Wrong. Every year people get the wrong ratio and I can't figure out why. Is it miscalibrated balances?

I have no idea. I wish I knew.

Friday, September 28, 2012

Sunday, September 23, 2012

Quicktime movies on some of my favorite chemistry topics.....

I found these and thought they were really helpful in explaining some fundamental concepts in introductory chemistry:

1. Periodic Trends video
2. Multiple Proportions video
3. Electron configuration and orbital energy video
4. Rutherford Gold Foil Experiment/Nuclear Model of Atom video


video

video
video
video
All four of these topics were emphasized on my first exam.

Saturday, September 22, 2012

Access Technology Here I Come!

Overview of the relational structure of the database

This is a picture of an access database relationships window. I pulled this off the web (it is random). However, it looks very, very similar to the way MY Access database looks.....

You see, this semester I'm trying my hand at adding all my grades to a comprehensive Access database. With this in place, I can control all spreadsheets from a master spreadsheet. It eliminates the need to update multiple spreadsheets when someone drops the class or I'm tallying overall scores throughout the semester. So far I've only verified that it works for dropping a student. I can drop someone from the master spreadsheet and their scores/name will be dropped from all of the linked spreadsheets. This eliminates so many steps for me!

The problems I am encountering make the process a bit rough. For example, do I have to manually set the data type for every cell throughout the database? I'm finding it a pain to alter my number cells so that the database accepts decimal numbers instead of just integers. I'm also finding the "sort' function a bit tricky. I sort by last name alphabetically only to find my spreadsheet resorted according to increasing student number. It is really frustrating to paste data only to discover the students were in the wrong order.

For all of these reasons I keep a backup excel document on my hard drive. If I ever lose anything important I can find it later.

I am so excited to take advantage of this technology and save time in the process.
Gold star, gold star gold star!

Tuesday, September 18, 2012

measurement and uncertainty

I am grading labs right now and reflecting on the importance of not only reporting a measurement with the correct units but also including the correct number of significant digits. This is critically important in science. The more I teach this class the more I emphasize its importance. It is the number one reason people get marked down on their lab reports.

I read somewhere recently that there was a major error made by NASA as a result of someone using metric measurements as if they were English measurements. Can you imagine such an error being made by scientists at the level of NASA engineers? I certainly can't. Obviously their introductory chemistry instructors did not emphasize the importance of this critical skill and they were able to mask their ignorance in upper level classes. This resulted in a major problem with a NASA satellite up in space.

At the level of the earthlings, however, the individual errors result in nothing more than a lower grade on a test or lab report. Insignificant in itself, however, predictive of larger problems down the road.

Uncertainty is critical in chemistry. Measurements must be precise and accurate.

Friday, September 14, 2012

Juggle, Juggle, Juggle as a mom

A few days a week, I get up at the crack of dawn to drive up to Orange County to teach an introductory chemistry class. As much as I enjoy teaching the class, it would be so much more convenient to have it closer and a bit later in the day. But...... here I go again breaking my resolution to appear nothing other than completely content. No, no, no, no complaining for me.... EVER.....(See my posts about Gretchen Rubin's Happiness Project)

For this reason I relish days like today when I have NOTHING to do but sleep late, take care of my daughter and try to keep some semblance of a clean, orderly house.  On the sunny side, I suppose I should just be glad I have a day like today to relish. Some people get up at the crack of dawn every day just to make ends meet.

I'm going to enjoy the fall sunshine at the zoo this afternoon.

Monday, September 10, 2012

Listen. Write. Present. A Review



Listen. Write. Present: The Elements for Communicating Science and Technology
Stephanie Roberson Barnard and Deborah St. James. 2012. New Haven, CT: Yale University Press. [ISBN 978-0-300-17627-8. 192 pages, including index. US$22.00 (softcover).]

“Listen. Write. Present.” The three title words summarize this book’s purpose. Stephanie Roberson Barnard and Deborah St. James write a concise, thorough summary of the skills needed to succeed beyond the classroom in science and technology professions.
One reason Listen. Write. Present. is successful in reaching its audience is that it encompasses highlights from other communication books into a one-stop shop resource. For example, the writing section highlights important grammar and punctuation rules; of which many are found in Strunk and White’s The Elements of Style. The chapter on presenting includes tips about how to optimize the use of slides—information that is a condensed version from Garr Reynolds’s Presentation Zen Design.
Also covered are topics of networking, serving, and listening. These are always helpful soft skills to review and practice, but particularly necessary for advancement in science and technology. Networking, serving, and listening are also necessary skills in other professions. This book is practical as a guide for almost any career. The chapter about meetings includes a section about how to run an effective meeting. Having sat through many meetings unrelated to science and technology, I kept thinking about how I wished everybody, regardless of their discipline of study, would review these skills to create faster, more efficient meetings. Perhaps Barnard and St. James could modify their title to encompass additional career fields and garner a larger audience.
Listen. Write. Present. could be used as a job searching tool for scientists as it includes sections about interviewing and résumés. A helpful addition might be a curriculum vitae sample as it is often easier to understand format by example than by description.
Many of the traditional communications books do not include information on how to incorporate technology into professional communication. This book does. From helpful tips about email etiquette to tips about formatting PowerPoint presentations, technology is definitely emphasized as a critical component to current communication.
One goal stated in Listen. Write. Present. is to create a quick reference manual for scientists. Although this is largely successful for the general information about writing and communicating, I found a flaw in this book for specific disciplines of science. The writing chapter includes a section about writing in the active voice instead of the passive voice. In writing scientific papers in chemistry, the passive voice is the accepted format for publication in a journal. For the scientist trying to submit a paper for publication, this section would provide misleading advice.
However, for a general guide about how to effectively leverage soft skills to maximize career opportunities, Listen. Write. Present. is an excellent resource. With its detailed index and list of additional resources at the end, it is a one-stop shop reference for any scientist’s shelf.

Sunday, September 09, 2012

Nutrition Lesson 101

While I was pregnant last year it became evident that I had inherited my Swedish grandmother's tendency for anemia. Yes, I was iron deficient. So it has become habit for me  to look at the ingredients and nutritional information on the side of many household foods to see how much iron I am getting in a given serving. I am always trying to increase my daily intake of iron from common foods so I don't have to eat large amounts of meat or take a supplement.

For this reason I glanced at the black molasses jar that my husband was going to use for his breakfast. We keep it in the back of the fridge mostly for Lent, but he occasionally eats a special breakfast of molasses and tahini with his bread.

I did not know that black molasses contains 69% daily allotment of calcium per serving. (Each serving is 8 oz.)  This means I could chug molasses daily and easily get my daily allotment of calcium. (My other deficiency is usually calcium as shown by my thin fingernails and peeling toenails).

Sometimes the strangest foods seem to meet my nutritional needs.

Thursday, August 02, 2012

Fundamental Questions in Science......

There is a post over at the Curious Wavefunction (click here) that explores some of the questions that make science fascinating. At the most basic level, so much of what I teach relates to the theory of reductionism (as discussed in his article). In introductory chemistry we are breaking things down to their fundamental building blocks only to discover that what we thought were the fundamental building blocks can be broken down further and further.....An example of this would be the discussion of the atom as a fundamental particle. Then, subatomic physics teaches us that atoms are really not the smallest particles available. But- as chemists we still use atoms of elements as the fundamental building blocks of chemical reactions even though they are not the smallest pieces of the reductionist pie.

This article takes this theory even further to explain its limitations. Many critical questions in science cannot be explained by reductionism. For example, can we break down the processes of consciousness and the brain to the level of the function of a single neuron to explain the processes of the brain? This is apparently not occurring in an obvious way since neuroscience has been unable to explain the function of the brain this way. The theory of emergence is somewhat the opposite of reductionism but explains processes through a synergistic effect of many smaller actions- for example the overall result of neurons in the brain creates a larger effect than the firing of any single neuron within. I really like the authors picture of a termite  hill as an illustration here- the overall effect of the termite hill cannot be reduced to the actions of any one single termite.

This article gets to the heart of what I think really matters in academics and in science in general. To further the progress of mankind these philosophical issues need to be studied by more scientists in more fields. We need the synergy of all fields of science to really tackle these overarching and unanswered questions.

The next era of science can only lead us further into what seems like a dark, endless abyss of understanding right now. I bet that is how the scientific world felt on the advent of quantum theory and the end of the global nature of classical physics.

Friday, July 27, 2012

Tribute to Sally Ride, pioneer for women in science

Sally Ride has passed on to a better place. She has left behind a story, a legacy and the shadow of a woman who led the way in the crusade for women in science. Her achievements spoke for themselves.

She did not want to be known as the first female astronaut. She wanted to be known as someone who could get the job done. And I think that should be the goal of all women in science: to get the job done.

I met Sally Ride about ten years ago when the local Association for Women in Science (AWIS) chapter took a group of women up to UCLA for their Sally Ride Science Day. Ride owned a foundation that held outreach events periodically. We were lucky enough to attend one within driving distance in Los Angeles. Ride autographed my nametag and I chatted with her briefly. She gave a 1-2 hour presentation on her trip in space and on space science in general. Local schools, nonprofits and other organizations were invited to hold outreach booths at the event. Our chapter had a booth with some kind of science related to gummy worms. Although I cannot remember what we were demonstrating I remember our table was swarmed with junior high age girls.

Science marches on with the contributions and achievements of Sally Ride on its back. We can only hope the march recruits more of those like Sally Ride: those with drive to achieve, stamina to persevere and resolve to get the job done. Goodbye Sally!


Wednesday, July 18, 2012

eggplant for dinner - garnering interest in fruit phenolic constituents

Tonight I added an eggplant to our chili just to see if my husband would say anything. Eggplant holds a position of some importance in the menu choices at our house as it is a staple of the Mediterranean diet. When we go out (or order out) for Persian food we usually include an order for some eggplant stew (with or without the veal in it). During Lent this is my husband's favorite meal- vegetarian eggplant stew from our favorite Persian restaurant.

I looked up the nutrition information about eggplant on the Internet and found this:



Eggplant is:
  • Low in Saturated Fat, Sodium, and Cholesterol
  • High in Dietary Fiber, Folate, Potassium, Manganese, Vitamin C, Vitamin K, Thiamin, Niacin, Vitamin B6, Pantothenic Acid, Magnesium, Phosphorus and Copper
The nutritional value and health benefits of eggplant makes it ideal for:
  • Maintaining optimum health
  • Weight loss
Don't include too many eggplants in your diet if you're interested in:
  • Weight gain
 Since I am currently still losing pregnancy pounds this piqued my attention. Is there any chemical in particular that makes eggplant good for weight loss? I'm really interested.


Here is a quotation from the chemical literature about eggplant:

"Eggplant (Solanum melongena L.), fruit commonly known as
aubergine, melanzana, garden egg, brinjal, or patlican is ranked
amongst the top ten vegetables in terms of oxygen radical absorbance
capacity due to the fruit phenolic constituents (Cao, Sofic,
& Prior, 1996). The colour, size, and shape of the eggplant fruit vary
significantly with the type of the eggplant cultivar, and its fruit is
commonly cooked as a vegetable in many parts of the world. The
cultivated eggplant has significant economic importance in many
tropical and subtropical parts of the world. In the United States,
the consumption of eggplant is increasing due to growth in ethnic
diversity and greater awareness of the health beneficial effects
associated with increased consumption of fruits and vegetables."

(Polyphenols content and antioxidant capacity of eggplant pulp, Food Chemistry,
Ajay P. Singh, 2008)

Friday, June 22, 2012

Periodic Table of Videos

I just discovered this rendition of the periodic table:  click here

It is a perfect way to slowly learn about each element on the periodic table. You click on each element and hear a simple tutorial about that element. It would be ideal to listen to 3 a day, for example, and then realize that at the end of 7 days you had learned about 21 elements.

I think I'll make this my summer goal. By fall I will be well versed in ALL elements on the periodic table.

Wednesday, June 20, 2012

How To Stop Science Alienation Syndrome - Deborah Blum on k-12 education (Slate)

Today there is an article on the Slate website by Deborah Blum about k-12 science education. The article can be found here.

Instead of leaving a comment at the end of the list of 102 comments I decided to blog about this entry. (This, by the way, delays publication of my blog about infant nutrition that I was going to do today.)

Blum's idea is to create tracks for K-12 students so that everybody is required to take four years of science education. There would be a track for future scientists, a track for college-bound poets and perhaps a track for noncollege bound, vocational-type people. (Or something like that- details to be worked out as needed.) Overall, I think this is a good idea, however, I have a few hesitations when it comes to "tracking" people.

The problem with creating tracks in science is the same as the problem with creating an "honors" program in the humanities. While I agree that we need to accommodate more science education into our schools,I'm not sure this is the place to start. Here is why:

The tracking system creates cliques of people. It is exclusive. It leaves out people that were erroneously placed in the wrong "track" and have forever been bored out of their minds. Sometimes it even creates situations where higher level work is going on in a "lower" track. I can say this from personal experience.

I started my high school honors program in the 7th grade and completed every year of it through my senior year in high school. Except one semester, I was in it all the way. Yes, we read more books, generally produced more papers and generally worked harder than the regular classes did. But we were also left out of a lot. During the semester that I spent in the regular classrooms, I saw the variety of people and socioeconomic classes at my high school. I met people I'd never met before and worked with people I never knew were interested at all in school. I saw some discipline problems in those classes as well.

Did that experience make me work less hard? No, it didn't. It made me appreciate my own love of literature, history and the arts. It made me appreciate that I care and some of them don't. But- most of all it taught me that I really wasn't that different from the people in the lower track. There were times when I felt the discussion was more lively, more engaging and more intellectual in the classrooms of the lower track. So all this leads to the question of what the upper track was doing that was really all that special?

We did have more required coursework than the lower classes. But- I think that in the end a lot of the higher track was just a reputation, a group of exclusive people who thought we were better than the average student. And in some cases we really weren't.

My current experience at the local junior college has taught me that it is very helpful to teach chemistry "warmup" classes to students who want to take college-level chemistry (for whatever career track be it science or medicine). For three semesters I have taught various renditions of a chem 100 class. For one school it is strictly for nurses. For one school it is for all prescience majors (premed, prenursing, preengineering mostly).  I have observed one important thing about the course description and how it makes people feel.

The students who take a class that has a label of being for beginners, nonmajors, nonscientists, etc are generally labeled as less intelligent. They have less confidence and generally perform more poorly.  But I'm not always confident that they have less ability or even interest. In this section of my chem 100 class I cover more chapters of the textbook, give more tests, and expect the students to do more experiments than those in my section that is geared toward engineering and medical school students. Its almost as if someone overcompensated the standards and decided that the nursing majors really need to prove themselves in chemistry to get their degree. In some cases, I feel the content is not really fair- it is a lot of information that is cherry-picked from a diverse area of the field. It's not well covered in the text. For this reason, I include extra handouts on my blackboard site. (I do not have those handouts in my premed class because we don't cover that topic.)

The point is that the designated levels that these chem 100 courses are supposed to fulfill are not consistent across schools and disciplines. It is luck of the draw to know how difficult of a chem 100 course you are going to get. It depends on which teacher you get, which school you take it at and during what time period you take the class.

Does this type of tracking make me confident that we can successfully "track" k-12 students? No, it doesn't.  It is too subjective as to what the people in charge feel are the standards at any given time.

I can confidently say, however, that having a chem 100- style class that students take prior to taking college-level chemistry is very helpful. Sheepishly, after teaching this class I actually understand the concepts on a deeper level because the class is presented strictly from a conceptual point of view. So often in general chemistry it is the manipulations of formulas, getting the right answer and the math that everybody gets so hung up on. While this is an important part of introductory chemistry, the more important part is getting people to understand the large concepts behind the math and the details.

The textbooks that I've worked with in this class include Bauer, Tro and Zumdahl. Each has its positive and negative points but all three have something in common: a focus on concepts.

So here is my proposal for updating science education in the future: Regardless of what the career goals of any individual are at any given time, students should be allowed to focus on concepts. This means professors and teachers will administer essay tests in the sciences. People need to be able to explain the behavior of an electron rather than just plugging numbers into an equation for an answer. I also propose more integrated programs of sciences with humanities, literature and the arts. Perhaps if we studied the lifestyle and literature of Richard Feynman in English class while we poured over the atomic bomb physics in science and studied the socio-political climate of Europe and America during this time in history then so much more of the science would be relevant.

Tracks can be helpful but the coordination of too many people is involved. I vote to streamline the classes into one big group of people. Then, propose honors/AP level projects that each student can take on as they have the time and interest. This allows anybody who wants to be involved  to perform at this level. Enough of exclusivity in education. We have enough of that already.