Friday, July 1, 2016

Do you have the periodic table memorized?

When a student asked me this question, I didn't. But, let me tell you the story of how I did it.

Why would anyone even do that?
Teaching/learning chemistry is not an easy task. Atoms and molecules are so small you can't touch them, chemistry has it's own vocabulary, and much of the day to day work is math-based. During a visit with a student in early 2016, an idea popped into my head. One of the things that makes chemistry hard to learn at first is that there are some things one just has to memorize. I wondered if it has been so long that I had been a student that I had forgotten how hard it is to learn and memorize new things. Maybe if I put myself in the students shoes, I could share some insights about learning with my students.

The challenge
I decided to memorize the names and symbols of the elements in order. I made a template with two on a page.


On my first attempt, I was pleased to find that I could already recite the first 20 or so from being in the discipline. For the elements I was unfamiliar with, I transcribed those one by one from the NIST version (yes, there is actually more than one version of the periodic table):
http://www.nist.gov/pml/data/images/illo_for_2014_PT_1.PNG
To start learning those I didn't know, I leaned on my experience trying to memorize piano pieces; focus on rehearsing small chunks. The first real block I had to work on was the transition metals (scandium, titanium, vanadium, etc.). Once I knew that section by heart, I started the next row. Regardless of how much I knew, I completed at least one template each day by transcribing each element I hadn't memorized yet.

This "chunking" technique worked well, but it really only worked within a chunk. It was hard to remember which chucks were connected. For example, transitioning from zinc (Zn) to gallium (Ga) was hard to do quickly. This is where the daily writing out of the whole table really helped. That recall experience started stitching together the chunks of information.

Other things that helped
Elements 57-71 were particularly tough; how was I going to efficiently learn this completely random list of 14 names and symbols? I was regretting the pact I made with myself to avoid mnemonic devices (like in music, "Every Good Boy Does Fine" help you remember that the treble clef lines are EGBDF). I made that decision because I didn't want to have to try to remember one thing to try to help me learn the thing I was trying to remember.

Looking to learn something about the individual elements, I went to YouTube, which helped a ton! I learned some interesting tidbits about individual elements, so that they were no longer strangers to me. For example, I had a hard time remembering that hafnium is right below zirconium. On one of the videos, the author talked about how zirconium is very difficult to purify because hafnium is a significant impurity. These two have similar chemical behaviors, and they are found together in zirconium ores.
https://www.youtube.com/watch?v=gNJE2MPktvg
Wow, that is helpful! That's the point of the periodic table, right? Elements in a column, have similar properties. This little tidbit made hafnium easy to locate and gave me a mental roadmap to find my way as I wrote it out each day.

Other interesting patterns emerged; praseodymium precedes neodymium. Also, actinium precedes protactinium by two spaces on the table, and it turns out was almost named protoactinium. Berkelium is right beside californium (Berkeley is a major city in California). Terbium, erbium, and ytterbium are all close together as well. The more time I spent with the periodic table, the more patterns I began to recognize. All this stuff was in the periodic table, and I had no idea! I was energized that this interesting stuff was right under my nose and I never knew. I became addicted to learning about the periodic table for a couple of weeks.

The bulk of the learning work was recall, which was obvious when I had others check me against a print out of the periodic table. Sometimes, as I was going along, I'd get stuck on an element. If I paused too long to think about it, some checkers would shout out the next element in line. My brain had been working on it, and when they said the answer, it like like a big "duh," floated in my mind. Interestingly, whenever that happened, I would get stuck in that same place the next day. However, when my daughter refused to tell me, or even give me a subtle hint something interesting happened. I told her I really didn't know and had no idea. I just couldn't think of what was next. She said, "Dad, you have to know it, it's your favorite one!" Then I knew, it was promethium; I never forgot it after that.

Success!
To be able to write it out from memory, it took about 15 minutes/day of practice for three weeks. But, it took me an onerous 5 minutes to write it all out. I practiced writing it out twice daily for another week, and got my time down to 2:50 (min:sec). Feeling encouraged, I decided to take my side show on the road -- time to show my students in class! My template was projected using a document camera, and my class was watching me like a hawk. I was trying to go as fast as possible; I didn't want to waste too much class time. They caught me, for one of the elements I said the name correctly but wrote the second letter incorrectly. Since I teach two classes back to back, I made sure I didn't make that same mistake the second hour! Both classes were genuinely rooting for me, applauded the presentation, and I got a chance to share some of the insights I shared in this post. I enjoyed the experience overall, and I hope that the students walked away with some good ideas about learning.

Forgetting
The story doesn't end there, though. After my addiction period, I had practiced for about a week more trying to make sure the info stuck. But, life happens and I just got too busy to keep it up. Around finals time, I realized that it had been several weeks since I had filled out a template. Here was the test of what I had really learned. On my first practice: 4m19s. Ouch! Even worse, I made 2 mistakes. I felt surprised, and a little deflated. I tried again; 3m21s, and no mistakes. The next morning, I tried again. 4:20 with one mistake. Immediately, I took one more stab at and broke my record - 2:43 and no mistakes. My best time was 2:31 one day later.

The moral of the story
I've heard it said, but have not confirmed, that first year chemistry students have to learn just as much new vocabulary as first-semester Spanish students! So, I think the moral of the story is, when you are learning something new, it's important to deliberately memorize some of the basics. Having quick access allows you to get to the deeper parts of the conceptual knowledge.

Sunday, November 18, 2012

How can chemistry help me clean hard water stains?

A basic knowledge of chemistry can make cleaning a snap. For example, you know those "hard water" stains in your bathroom? No? Oh, it looks like this . . . see the picture at right. They call it "hard water" because the water supply has a significant concentration of minerals such as calcium and magnesium. The nasty process starts when you leave the shower. The bathroom hardware is wet with water droplets adhering to the metallic surfaces. The thing is, the water droplets evaporate, but the minerals don't. The minerals actually crystallize onto your tub spout and handles, leaving behind a water-drop shaped  stain. Compounding the problem is the fact that soap also leaves behind a film. 

As an interesting side note, this means that if we could take showers in pure water, there wouldn't be spots right? Yes, that's why window washers use purified water to clean windows that are hard to reach with a squeegee. Once they scrub off all the dirt, the water will evaporate, and since there are no minerals in the water, it evaporates without spots! 

So, what is a human to do when it's their turn to clean the bathroom? The untrained bathroom cleaner, will pick up a bathroom cleanser and rely on muscle power and time. While this will get the job done, it exhausts two precious resources of a lazy person . . . time and effort. Another unfortunate consequence, is that many cleansers have some type of grit in them which works like sandpaper to remove the finish from the hardware. Eventually, the bathroom hardware will have to be replaced because it will look like it is prematurely 30 years old. 

The chemistry-wise chore doer uses those same resources, time and effort, to his advantage. The only difference is that chemicals are using time, and doing the majority of the work. See, the hard water stains are weakly basic like soap. Since most cleansers are similar, they are not very effective on hard water stains. One common pattern of chemicals reactions, is that acids and bases readily react with each other. So, what is a good acid to use on the water spots? Hydrocholic is too strong for typical cleaning, and will probably dissolve your skin away. But acetic acid (known to the populous as vinegar) is a weak acid which will react with hard water stains to create chemicals which will wash right down the drain. Here's what you do:

1. Buy a cheap spray bottle at the grocery store. 
2. Fill it with vinegar from your kitchen - do not dilute it.
3. Use the bottle to spray and soak the offending hard water stains. If you hate the smell of vinegar like I do, turn on your bathroom fan. 
4. Come back in 5 minutes. This allows the vinegar to soak into the deposits, and neutralize them. This is where you get to save the time and effort! If you care about the chemistry, here is a simplified example of the reaction . . .

CaCO3 + 2 HC2H3O2 --> Ca(C2H3O2)2 + H2CO3

5. Now, get your scrubbing implement, and wipe the stains away. It may take a little elbow grease, but not nearly like it would have without the vinegar. If there is a significant buildup, you may need another treatment. Here is an specific area that I scrubbed with a q-tip soaked with vinegar (compare to above):

An alternate that costs some money, is to employ a water softener. A water softener exchanges minerals in tap water with sodium, which is very soluble, and doesn't accumulate to the degree that calcium and magnesium do.

So, what do you really gain from this approach? 5 minutes saved where you weren't scrubbing, you've saved the frustration of the effort, saved the finish on your hardware, and felt the satisfaction of wielding your chemistry know how to work for you!




Monday, October 29, 2012

OK, so this isn't a question like the rest, but a few students asked me to help with a portion of their video. I've got a cameo in the following, can you find me?

http://youtu.be/tqfX3plrKdM

Friday, October 12, 2012

Does body language really matter?

photo from: http://commons.wikimedia.org/wiki/File:Evita_dando_un_discurso.jpg
File:Evita dando un discurso.jpg

Does it look like the person in the picture above is trying to emphasize a particular point? What emotion is she trying to attach to what she is saying?

In one particular lecture about presenting scientific research, I spend a few minutes talking about body language. Inevitably, a student usually asks this question, "do people place arbitrary meaning on body language, or does it really matter? The following video answers that question very well in the first 3-4 minutes.

http://www.ted.com/talks/amy_cuddy_your_body_language_shapes_who_you_are.html

Need another example?

http://www.youtube.com/watch?v=_U9RfxYR5XA&feature=related

This one is just as interesting:

http://www.youtube.com/watch?v=evpn-U3t-i0&feature=related

Body language don'ts . . .

http://www.youtube.com/watch?v=VfE7aVa_mSo&feature=related
http://www.youtube.com/watch?v=9PHwaE6rd4c





Thursday, October 4, 2012

Do you have a question?

Do you have a question I could answer? What is something you have always wondered about?

Friday, September 28, 2012

What is your favorite chemical demonstration?

I like them all! However, one that I have put considerable effort into is a chemical demonstration themed on the 1812 Overture. It has 12 cannons using methanol as fuel. The original score by Tchaikovsky has the normal instruments, and then at the bottom, it actually has a line and notes for "Cannons." You can see the apparatus here:

http://www.youtube.com/watch?v=5jdxLQSEq80&feature=g-upl

It was programmed in LabView, built in our instrument shop, and spews fire like a dragon!


Tuesday, June 5, 2012

Can a tattoo be removed?

How could a tattoo be removed?

First, what is a tattoo made of?
Ink is made of large molecules. The molecules are large enough that the body doesn't just haul them off as junk. So, the molecules just sit there, because in essence, the body's defenses doesn't recognize what to do about this large molecule siting there.

Second, how can a tattoo be removed?
If we could break up the molecule into smaller pieces, the body could recognize the fragments and digest the left over pieces. Bring in the laser . . . A laser imparts energy to a molecule with an electric field which causes the bonds within a molecule to vibrate more than they already do. So much so, that it breaks the bonds. It's terribly effective . . . take a look:

http://www.wimp.com/lasertattoo/

Sometimes there is minimal scarring, and not all of the ink may not have removed, but if you have a tattoo that says, "Bertha," and you married Grazelda, you're probably going to be OK with it.