Shrimp and Grits

Many college-level science courses begin with what, for the students, should be a brief review of the basics of the scientific method. After all, without any hint of the method behind the science in a course, a science course becomes a jumble of facts to memorize and regurgitate on command.

Sometimes, though, these beginning exercises in the methods of science can turn into frustration for instructors, who have to wrestle with the deficiencies of students in other areas. In particular, many students aren’t able to separate needed information from unneeded information.

Here’s an example.

The assignment:

You wake up one morning to find the power is off in your home. There can be a number of reasons for no power…I’ll let your imagination run wild as to the other observations that you might make to help you figure out the cause. Formulate 1) a hypothesis and 2) a prediction based on your observations; post them as a reply to this message.

As you can see, this isn’t exactly a foreign situation to anyone who lives in a modern home with lights and electricity.

Here’s one of the responses:

I woke up late for work one morning because the alarm clock didn’t go off. When I looked at my cell phone to see the time, I immediatly jumped out of bed and threw the light switch up, no light. I went in the bathroom and threw that switch up, no light there either. The power was out. I do remember hearing thunder last night and I know that there were severe thunderstorm warnings and watches all around until late into the night. The storm must have caused there to be a power outage and the power company had not yet been notified. I quickly got dressed and flew out the house. On the way to work I called the power company to report the outage. Thank goodness for cell phones.

So what’s wrong with the response? Well, other than the fact that the imagery associated with the phrase “I went in the bathroom and threw that switch up” reminds me of the ipecac scene in an old episode of Family Guy, I don’t think the point of the assignment was to write a short essay in praise of the cellular phone. You could actually make a few hypotheses and predictions from what this student has written, but the student doesn’t actually point any of them out.

While this particular example isn’t from any of my classes, I do run into a lot of the same kinds of answers. Students have an inability to extract relevant information. It’s no wonder that these students have trouble with the sciences, where stripping away unimportant detail is fundamental to explaining why things work.

But why do students have these problems? Is it a lack of training in early years? (Is the problem-solving that students do in high school so contrived that students never have to actually think about details and whether they are important?) Is the “info dump” style of answering questions (as demonstrated above) rewarded somewhere along the line? (I’m thinking that partial credit might play a role here.)

Any ideas?

Let’s say you don’t want to do the thermite reaction, but you still want to see some very neat looking violent chemistry. The reaction between aluminum and bromine might fit the bill.

2Al(s) + 3Br₂(l) –> 2AlBr₃(s)

It’s a very simple reaction, but it’s also very exothermic, and can put on an impressive show. Not only is enough heat generated to melt the aluminum metal, but the heat also vaporizes some bromine, producing huge clouds of white and orange smoke. For obvious reasons, this reaction should be done where you’ve got very good ventilation. I used my hood for these pictures and this video.

Here’s a still image of the reaction vessel containing only liquid bromine.

Liquid bromine and its vapor.

Bromine is the dark red liquid at the bottom. Bromine is quite volatile, and you can see orange bromine vapor in the top of the beaker.

About ten seconds after adding some torn aluminum foil, things look more like this.

Reaction!

A little later …

Things begin to heat up! (Click to enlarge)

Oh yeah!

Now we’re cooking! (Click to enlarge)

Want to see the video? Here are a few links to a 30-second video file with audio:

• AVI file, uses MPEG4 video and MP3 audio, 805K: This file plays fine under Linux using mplayer or xine. You Windows folks may have trouble with it without installing extra codecs.
• WMV file, 889K: Plays even on my stock school-issue Windows XP machine with Media Player

The aftermath of the reaction is interesting. Some of the aluminum foil melted and fused with the bottom of the beaker.

Aluminum fused to the beaker

Needless to say, we won’t be using this beaker again.

You can see the aluminum bromide product on the sides of the beaker.

Aluminum bromide (white / yellowish solid) on the beaker

The aluminum bromide formed will react with water, causing the release of hydrogen bromide (very nasty to breathe - acidic vapor), so you need to be careful disposing of the product! That reaction is also very exothermic, so touching the product or adding water to it is not recommended. Leave it out long enough, though, and it will absorb water from the air on its own.

Ain’t science neat?

Disclaimer: Do not try this reaction at home. In fact, do not try this reaction at all! You were warned.

Updated with more pictures and video: 04/25/2006

Sometimes, when you grade papers, you have to laugh to keep from crying. I’ve been teaching chemistry to college sutdents for a number of years now, and I keep a file of some of the strangest student answers I’ve ever received. I didn’t keep what I dubbed the “e.e. cummings lab report” - written without any capitalization or puctuation - but I do have a few of what I call “Classics of Student Literature”. Here is one of the classics.

Once upon a time, I asked some of my students on an exam to use the valence bond model to explain why there were two distinct forms of the dichloroethene molecule: cis-dichloroethene and trans-dichloroethene.

cis-dichloroethene (Chlorine atoms on the same side)

trans-dichloroethene (Chlorine atoms on opposite sides)

I also told the students in the question that the cis form has a larger dipole moment and a higher boiling point than the trans form. The students were merely asked to explain why there are two forms of the molecule in the first place. Since they’d just studied sigma and pi bonding, I was expecting an answer that mentioned that since the double bond contained an off-axis pi bond, that rotation of the molecule around the double bond (changing the cis form into the trans form or vice versa) would not be easy. The pi bond would have to be broken for the molecule to rotate.

Whether you remember enough freshman chemistry to make sense of the above paragraph or not, you might appreciate one of the answers I was given.

In cis molecule that is polar with a higher boiling point is different than the trans molecule. It has a double bond between C atoms. The shape of the two are the same but each one is different in other areas. Because of the structure + make of the cis and trans molecules is the reason it is able to exist. Both have the double bond between C atoms. But because one is polar and the other is nonpolar due to the charges it produces makes them able to exist. They also have different BP which makes them 2 different atoms. Because one is polar and one is nonpolar they have different properties which makes them different atoms that can exist.

Say what?

Several years ago, I asked a large class of introductory chemistry students to name H₂CO₃. Since we had just been over the oxyacids (acids that contain hydrogen and oxygen in addition to other elements), I expected nearly all of them to give me the name carbonic acid.

I was mistaken. While many students did indeed identify the compound as carbonic acid, I got many other responses. Here they are.

1. hydrogen carbonate
2. hydrogen oxide
3. hydrocarbonate acid
4. dihydrogen tricarbonate
5. hydrocarbonoxide acid
6. dihydrogen carbonate
7. dihydrogen tricarbon
8. dihydromonocarbontrioxic acid
9. dihydrotricarbonic acid
10. dihydromonocarbonic acid
11. hydrogen cardonate
12. dihydrogen tricarboxide
13. dihydrogen tricobalt
14. hydrogencarbonic acid
15. dihydrogen tricarbonite
16. hydrocarbonous

Kinda makes your head spin, doesn’t it?

Via Pharyngula and Unscrewing the Inscrutable, Meet Tom Ritter, a high school chemistry and physics teacher who seems to be a little out of his element. As a chemistry teacher myself (though at a two-year college), it bothers me to see a colleague become a fountain of stupidity. (I would prefer that chemistry teachers stick with ammonia fountains instead.)

What’s Tom going on abiout? Well, evolution, of course! He doesn’t like it. He and the Constitution Party of Pennsylvania want to have a debate, because he doesn’t think that evolution is “true science”.

It’s more likely that the (fringe) Constitution Party merely wants some publicity in the local newspapers, but that’s another issue. It might also be possible that this whole article is close enough to April 1^st to be a parody, but I’ll pretend for the moment that Tom and the Constitution Party are serious.

Here are Tom’s problems with evolution:

1. No one has demonstrated that life can evolve where none existed before.
2. No one has demonstrated that a new sexual species can evolve.
3. Evolution theorizes the human brain evolved from lower forms of life. Over 50 years into the age of computers, we can build machines that can crunch numbers far better and faster than humans, recognize and use language and tools, and beat us in chess. Yet science has yet to build even a rudimentary computer than can contemplate its own existence, the hallmark of the human brain.

1. Evolution, as most people who have ready anything at all on the subject would know, describes what happens after we have something resembling life - i.e. things that can reproduce and pass on characteristics to their offspring. Tom’s problem seems to be abiogenesis, which no scientist is going to argue has been completely worked out.
2. This one I’ll leave to a biologist, but I’d recommend a search for speciation on PubMed. Is Tom’s argument the new creationist version of “No new species have been observed”? Gotta love those moving creationist goalposts.
3. So we don’t understand all the details about how the brain works. So what? In what way is that a failure of evolutionary theory? I’ll bet that Tom can’t tabulate for me either manually or with his chess-playing computer the momentum and position of every electron in all the atoms of a gallon of gasoline. Does that mean that he cannot possibly tell me how an internal combustion engine works?

With every one of these criticisms, Tom seems to be telling us that since biologists don’t know everything, they can’t know anything. That’s a dangerous position to take if you’re a chemistry or physics teacher. Does this guy teach atomic theory? Valence bond and molecular orbital theory? Kinetic theory of gases? Classical mechanics? The gas laws?

Further on down, Tom says something else that’s not really related to science, but is pretty silly anyway.

God with an upper case G is the Being recognized by Christians, Muslims, Jews and many others to possess remarkably similar traits, among them the ability to create.

Tom, you just try to tell some of these folks that they worship the same “Being” as the Christian God. I don’t think they would buy it.

Evolution may be right, at least in parts. But it is not treated as science and materialism is a faulty theory to rely upon.

Tom, in a footnote, defines materialism as “the theory that everything can be explained by things that can be detected and measured”.

Tom, do you know that’s how science works - by investigating things that have effects that can be tested and measured? Do you know that evolutionary theory is based on things that can be tested and measured, just like all the other scientific theories? If you don’t know this, then how the heck can you manage to teach science in the first place? Or do you just reject the science if it tells you something that you are unprepared to hear?

While doing a little research on South Carolina education, I came across a group called SC PIE, a “a grassroots organization committed to excellence in the public schools of South Carolina through the meaningful involvement of parents in children’s education”.

Their website suggests that they’re mainly a group interested in two things - putting religion in the science classroom and giving tax money to private schools. But this is the wtong blog for serious discussion of issues. You came here for funny stuff!

You can access this group’s newsletters online, as PDF documents. Here’s a sample, from December 2004.

Looks to me like the writer’s mind was decimated before she finished the headline!

While it’s not nearly as bas as this stunning example, the Greenville News has another painful-to-read letter that shows us why we need to strengthen science education.

Education based on false hypothesis results in faulty logic and reasoning.

Evolution is unsubstantiated theory and problematic with many scientific and mathematical laws. Carbon dating doesn’t allow for appearance of age at creation. Basic scientific facts and medical cures are totally dependent on a constant state of matter. Minor change occurs but everything still brings forth after its own kind. Genetic manipulation confirms creation. Man, created in God’s image, on a small scale imitates God.

I mean, where do you start with someone like this? Carbon dating’s not used to determine the age of the Earth, for one.

Nest, I’d ask this writer why he doesn’t believe that the universe was created last Thursday, since he seems to believe that his god is a trickster who creates things “with apparent age” - presumably to fool folks who honesty try to figure out what is going on.

The writer (ironically) mentions a “constant state of matter” - which I’m guessing means that he assumes that the properties of matter (like radioactive half life) don’t change over time. Of course, he doesn’t like the conclusions that scientists draw from this about the age of the Earth.

In short, he seems confused about every bit of science he mentions.

Of course, I don’t know the writer’s age and if he is actually a product of South Carolina’s educational system - there’s not enough information in the rest of the letter to tell. But if he’s a fair sample, we have a lot of work to do.

CNN and BBC are reporting that a chemistry laboratory at the National Institutiuon of Higher Learning in Chemistry at Mulhouse has exploded, killing a professor and injuring others.

Some reported that the explosion could be heard a mile away, and there’s no word yet on what caused it.

The story so far is too sketchy for me to even speculate on what caused the explosion.

A person on the chemical education mailing list I subscribe to posted this opinion.

Apart from this accident, such chemical incidents give a negative connotation to the layman (and future students) - chemistry is dangerous.

Well, chemistry is dangerous - as are many things. That’s why chemical educators should be extremely cautious in the laboratory, especially when working with students who have little laboratory experience.

PZ Myers has a post up about how Arkansas sutdents aren’t being taught evolution even though it’s in the state standards.

Arkansas is not alone.

An editor at The State tells us to not worry about science teaching challenging some religious beliefs because teachers aren’t teaching the science anyway.

Dr. Woodall [Union High School principal] learned about Charles Darwin’s origin of life theory at Furman University, when it was still a Baptist school. She didn’t buy the idea that life evolved randomly, or that human beings can be traced back to single-cell organisms. But that didn’t limit her as a teacher, because biology teachers in South Carolina don’t have to teach that; she doesn’t know of any who do.

Well, I guess that explains something about South Carolina’s test scores. The standards aren’t the problem. We’re just not using them.

I’m sitting here grading chemistry tests and cleaning bits of my brains off the walls after reading one particular student answer.

Here’s the situation: We do a freezing point depression lab involving dissolving dichlorobenzene in cyclohexane and monitoring how the freezing point changes. Pure cyclohexane freezes at about 6.6^oC, and when the dichlorobenzene is dissolved into the cyclohexane, the freezing point drops a few degrees. The students use an ice bath to cool the cyclohexane enough for it to freeze while monitoring temperature with a digital thermometer.

On the test, I have a freezing point depression calculation - asking them to calculate the expected freezing point for a mixture of cyclohexane and dichlorobenzene (the same substances they have already used in the lab). To their credit, most students had no trouble with the calculation. One answer, though, just blew my mind.

The freezing point of the dichlorobenzene solution is 170 ^oC.

One hundred and seventy degrees Celsius. 70 degrees higher than water’s boiling point. For a solution that was frozen in the laboratory in an ice bath.

Ow, my head.

(This is what comes of treating real-world problems as math exercises without stopping to think that these numbers mean something.)