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.




Tuesday, January 17, 2012

What are your favorite web videos?

Absolute Favorites:
http://www.dump.com/2011/12/07/two-year-old-with-flow-video/
http://www.dump.com/2011/11/17/little-girl-joins-the-dark-side-video/
http://www.dump.com/2011/11/15/samuel-l-jackson-blame-video/
http://www.dump.com/2011/11/14/amazing-starlings-murmuration-video/
http://www.dump.com/2011/11/08/288000-jelly-beans-and-two-years-is-what-made-this-video-possible-video/
http://www.dump.com/2011/11/05/tomb-of-the-unknown-soldier-yells-at-laughing-crowd-video/
http://www.dump.com/2011/10/26/introducing-the-nest-learning-thermostat-video/
http://www.dump.com/2011/10/13/german-guy-on-rock-paper-scissors-video/
http://www.dump.com/2011/10/07/every-teenage-girl-should-see-this-video/
http://www.dump.com/2011/09/23/look-at-yourself-after-watching-this-video/
http://www.dump.com/2011/09/14/water-printer-in-osaka-japan-video/
http://www.dump.com/2011/08/08/the-front-fell-off-video/

Ever wondered what PI sounds like?
http://www.dump.com/2012/01/06/song-from-pi-video/

How to escape quicksand:
http://www.dump.com/2012/01/04/how-to-get-out-of-quicksand-video/

These people have skills, period.
http://www.dump.com/2011/12/03/power-of-the-pentatonic-scale-video/
http://www.dump.com/2012/01/01/firefighter-exam-get-to-the-3rd-floor-in-13-seconds-video/
http://www.dump.com/2012/01/01/guy-makes-iced-tea-like-a-boss-video/
http://www.dump.com/2011/12/22/crazy-mime-artist-in-manchester-england-video/
http://www.dump.com/2011/12/02/the-charleston-style-video/
http://www.dump.com/2011/11/29/laserman-show-at-disneyland-in-california-video/
http://www.dump.com/2011/09/21/hand-feeding-a-hummingbird-through-a-bedroom-window-video/

Great teaching moments:
http://www.dump.com/2011/12/29/japanese-children-learning-about-life-and-compassion-video/
http://www.dump.com/2011/12/07/mit-professor-draws-some-of-the-best-lines-video/
http://www.dump.com/2011/11/21/bruce-lee-be-water-my-friend-video/
http://www.dump.com/2011/11/20/quickest-personality-test-video/

Leading with purpose:
http://www.dump.com/2011/12/28/the-surprising-science-of-motivation-video/
http://www.dump.com/2011/10/17/how-great-leaders-inspire-action-video/
http://www.dump.com/2011/08/25/japan-airlines-ceo-who-cuts-his-pay-to-save-company-costs-and-improve-revenue-video/

Fun Chemistry or Science:
http://www.dump.com/2011/12/28/how-to-make-gold-from-metal-mercury-video/
http://www.dump.com/2011/12/13/trillion-fps-camera-captures-advancing-light-waves-video/
http://www.dump.com/2011/12/13/interesting-sulfur-hexafluoride-experiments-video/
http://www.dump.com/2011/12/09/some-traffic-jams-are-created-for-no-reason-video/
http://www.dump.com/2011/12/05/planets-viewed-from-earth-as-if-they-were-at-the-distance-of-our-moon-video/
http://www.dump.com/2011/12/02/the-charleston-style-video/
http://www.dump.com/2011/11/04/music-without-sound-video/
http://www.dump.com/2011/10/30/glowing-ripples-in-the-electromagnetic-field-of-planet-earth-video/
http://www.dump.com/2011/10/18/gps-and-relativity-video/
http://www.dump.com/2011/09/09/erasing-a-cd-video/
http://www.dump.com/2011/09/06/laminar-flow-video/
http://www.dump.com/2011/09/03/water-droplet-that-bounces-falls-onto-super-hydrophobic-surface-video/
http://www.dump.com/2011/08/28/from-a-japanese-tv-show-a-real-life-example-of-adding-vectors-and-relative-motion-the-truck-is-moving-at-100-kmh-and-a-ball-is-shot-backwards-at-100-kmh-resulting-in-it-coming-to-a-complete-stop/
http://www.dump.com/2011/08/23/richard-feynman-jiggling-atoms-video/
http://www.dump.com/2011/08/03/wireless-data-from-every-light-bulb-video/
http://www.dump.com/2011/07/14/ferromagnetic-objects-meet-a-4-tesla-magnet-video/

So bad, you just have to watch.
http://www.dump.com/2011/12/09/got-it-when-can-i-help-build-it-video/
http://www.dump.com/2011/12/09/kelly-ripa-and-neil-patrick-harris-inhale-sulfur-hexafluoride-video/
http://www.dump.com/2011/10/27/engineers-blow-stuff-up-with-science-video/
http://www.dump.com/2011/09/05/7-times-13-equals-28-video/
http://www.dump.com/2011/08/22/how-to-increase-your-wi-fi-signal-great-way-to-troll-the-less-tech-savvy-video/

This is a great perspective on an old emotion:
http://www.dump.com/2011/12/18/how-to-be-alone-video/

Why is the water pooling in the street?

The city just repaved our street. The next day it rained. When I came outside in the morning, it still smelled like tar outside, but I saw the strangest thing.  Water was beading up on the surface of the new asphalt in interesting ways. Here is a picture of it . . .
The pools of gathering water were about the size of the palm of my hand.  Because the road is sloped, one pool of water would morph into another to make larger pools which would roll down the street and into the gutter, like this . . .
It was quite an amazing site, because this was happening all over the street. A normal person might not care too much about this enough to stop an watch.  But, I was looking at the phenomenon as a great example of the difference between the molecules of tar and the molecules of water.

Molecules of water are small, and have an uneven spatial distribution of electrical charge. What's more for water is that because the atoms are small and polarized, they are able to strongly bond with each other.  Tar on the other hand, is a long chain of carbon based molecules, which are not polarized.  We perceive the water as watery, and the tar as oily. We all know from experience that oil and water don't mix, but this was a fun real-life example. You'll know you are a nerd if you look twice next time you are around tar during a rain shower.

Monday, January 16, 2012

Why is it so difficult for congress to agree on things?

Neil deGrasse isn't my favorite personality in the world, but I am so impressed with this clip:

Tuesday, January 10, 2012

Do you go through a lot of paper?

Last year, the syllabus, quizzes, and exams I printed for my students came to a total of 44850 prints.  That is almost 90 reams of paper!

For those eco-friendly readers, the testing center has been looking into how to do electronic testing for some time now. So, a more tree friendly method is in the works.

Monday, January 9, 2012

Do students ever say thank you?

Here is some example emails from the last 8 months:




Dr. Macedone,

This has been a long time coming but I am very good at procrastinating (one of my finest traits). I just wanted to thank you for the exceptional classes that I had with you and thank you for writing me a letter of recommendation for medical school. I am currently attending the University of Arizona - Phoenix College of Medicine and I am enjoying it. It is a challenge, but I quite like the challenge that it presents. 

You were my favorite professor at BYU and I wish that I had more opportunities to take classes with you in a smaller class setting but that is life in gen chem, right? Your classes were fun, interesting and informative. Sometimes I wish that some of my medical school lecturers could take some pointers from you (especially the neurosurgeons. I get that as neurosurgeon you know a lot, but you dont have to try to teach me everything you know and have ever done in one hour with the driest ppt ever, ha.). I just wanted to give you a shout out or even a 'holla' and say thanks for everything. 

I hope everything is going well at school and at home. I also hope that you can one day get another student that is as awesomely awesome as I am but its a slim chance. 

Thanks,

T


Hi Dr. Macedone,


I was in your 106 class in the winter, and I just wanted to send a quick thank you to you! Thank you for all of the time and effort you put into making chemistry worthwhile for all of your students. I always appreciated the enthusiasm and love of chemistry you brought to class and shared with us. I was grateful for the challenging nature of your class, yet the fact that success was possible! I hope you continue to teach and influence students' lives!


Sincerely,
D


Dr. Macedone,

This is M____, the student that came in Monday about iclicker points.  I just wanted to thank you for that conversation and your understanding.  I really appreciate how much time and effort you put into your classes and it was very clear from our conversation Monday that you are concerned with the success of your students.  Although I've struggled in this class throughout the semester, I do feel that I have learned a great deal due to your dedication to this class and making it a fruitful learning experience.  Thank you for your time and for a great class this semester.

Dr. Macedone,
I know that sounds pretty nerdy, but you made class very interesting and much easier to learn the subject. I am happy with my performance in the class, right up until the final. I studied like normal and got A's on all 3 tests, but did not do too well on the final. I'm not sure why, but the multiple choice really threw me off. I would be interested to know what the average was for the final compared to the other 3 tests. I was really excited because I thought I had pulled off an A in the class, and I will be REALLY bummed if I don't...I put in a crazy amount of time and effort, doing literally every single thing that you asked and suggested, but it is what it is. I feel good about myself and my effort, that's for sure. Most importantly, I learned a lot and I know that it will especially help me tons on the DAT next spring. I took a practice DAT about a month ago and it was very obvious that the things I was learning in your class are going to help me out. Anyways, thank you for all of your time...I made many trips into your office, right from the beginning, so I especially thank you for taking the time to talk to me and offer your counsel. I could really tell that you care about your students. Take care and have a great summer!!

Thank You for such a great semester. I really have enjoyed this class and appreciate everything you have taught me for everything. Thank You.

Dr. Macedone,
I just wanted to personally thank you for first fixing my iclicker score and second for the great class that you provided. I have to admit your class was my hardest class this semester and chemistry does not come naturally to me but as the semester went on I can honestly say that your class became my favorite class. I'm wishing now that I would have put in a little more time at the beginning of the semester to not just get a good grade but to really internalize these things because really it is a fascinating subject. Thanks for making the class not only entertaining but thought provoking. When you ended your lecture on thermodynamics and related it back to the gospel I think that was the first time in a non-religion class that a professor brought the gospel into the class in a meaningful way for me and it didn't seem like they were trying too hard to get some gospel aspect into the class. I will probably remember your class for a long time so I just wanted to thank you. I hope you have a good summer and if I get a chance to take a class from you again I'm sure I'll sign up for it. 

Dr. M,

Just wanted to drop you a quick note thanking you for your help today. As I told you before, I love chem despite my poor performance on the last exam. I do believe the right answer is important and I appreciate you helping us really learn chemistry down to the nuts and bolts. Thanks for your help and faith in us to do better on the next test. It means a lot.

R

Hey Dr. Macedone,

A couple years ago one of my friends took Chem 106 from you. Everyday after your class he used to get all excited and tell me about the things that he learned. He said that Chem 106 almost made him want to be a Chemistry teacher. I thought he was crazy... actually liking Chemistry? I get what he is talking about now, you're a great teacher, and I am really enjoying the class. Plus I actually get it for once (I think, I guess I will find out after exam 1). I just thought I would say thanks for the energy and spirit that you put into teaching, it helps a lot. 





Dr. Macedone!
I felt that I should send you a personal email letting you know how much I appreciate your chemistry class. You are such an amazing teacher and I've learned so much over the last couple semesters in both 105 and 106. Coming into 105 last semester my attitude toward chemistry was very negative. The only chemistry I had ever had before was early on in high school about five years ago and it wasn't very appealing even then. I had grown to love biology in high school but when it came to chemistry I struggled so much. You have done a fantastic job in helping me learn the value of taking my education into my own hands and making learning enjoyable. Your love and excitement for what you teach is sincere and contagious. Last Friday when the lecture was on titrations I realized for the first time in my life I actually loved chemistry! It was so fascinating to me as you helped us through the titration process putting together all of the knowledge we had learned up to that point. Recently I've found a greater appreciation for my chemical knowledge when it comes to biology as well and I feel that I have a greater understanding in my field of study because of it. I'm not the best student and I definitely can't say that chemistry comes easily to me but I can say that it is so much more meaningful to me now. Being enrolled in your classes has been the biggest factor for that change. I thought I'd let you know how well you're doing and I hope that many more students in the future have the opportunity to learn from you as I have. Thanks again!