Flouridation Controversy

A story on NPR last week about the debatable benefits of flouride in water got me asking questions about water flouridation. What form of flouride do they use? Through what mechanism is flouride in water supposed to help prevent tooth decay? What evidence is there that flouride might be harmful?

The first thing to notice is that it is flouride that is put in water, not flourine. Flourine is the elemental form -- this is what is listed on the periodic table. Flourine is a halogen; it is highly reactive and is rarely found on its own in nature. But, like all halogens, it can form a bond with itself and make a flourine molecule. Flourine (F2) is a highly toxic pale yellow gas. No wonder people are worried about putting it in water. But remember -- it is not flourine that we put in drinking water, it is floride. The difference between -ine and -ide is a big one, it is the difference of a single electron, but that single electron change the entire chemistry of the substance.

Flouride is a flourine ion, a flourine that has gained one electron and now has a positive charge. Where did it get that extra electron? Probably by making an ionic bond. Think of table salt: sodium chloride or NaCl. Chlorine is also a toxic gas, but when it makes an ionic bond with sodium, it forms the compound NaCl, which is not only not toxic, but necessary for a healthy body.

So back to flouride.

Whether or not to put flouride in driking water is a debate that has been raging for years. According to a story from Chemistry and Engineering News from 1988, it looks like many claims are still at issue. Here is what the government has to say about things right now. Have ideas changes since 1988? Do we have new evidence to support either side? What is your opinion?

Meet Friedrich!

Room 112 has a new inhabitant: Friedrich, the red-eared slider. Friedrich is about five years old and he has lived in captivity his whole life. Red-eared sliders are indigenous to new england and their range extends throughout North America. These turtles are aquatic, but because turtles are reptiles, they do breathe air. If you are interested in learning more about red-eared sliders, or turtles in general, I invite you to do some research and post what you learn on the blog.

Science in 2010

The new year is always an opportunity to review the year past and many blogs and magazines have assembled their top 10 lists of science moments from 2010.

Scientific American does their 2010 review with a slideshow.

The New York Times assembled a list of the top 10 environmental stories of 2010.

The BBC offers both a review of 2010 and a preview of 2011.

And Discover Magazine (always an overachiever) presents their collection of the top 100 science stories of 2010.

Amongst all of these summaries, the LCH gets a mention. Just to refresh your memory, the LHC is the particle accelerator in Switzerland that is looking for the tiniest subatomic particles. They have had many breakthroughs this year, but still no solid proof of the most elusive particle -- the Higgs boson. Have you ever wondered what a subatomic particle sounds like? How about what it looks like?

Final Steps

On Friday, we will wrap up the fish kill problem. Hopefully every group has completed their graphs and at this point you probably have a pretty good idea of what may have caused the fish kill. The presentations on areas of expertise should confirm your suspicions. Here is the agenda for Friday's class:
1) Groups present areas of expertise in front of class.
2) Individual groups reconvene to make conclusions on the cause of this fish kill, using what you now know about the possible causes and your analysis of the data. Prepare to present your conclusions to the class. Make sure you back up your conclusion with evidence. (Talking about your answers to questions 1-3 in the Data Analysis might help guide your conclusions).
3) Groups present their final conclusions to the class and as a class we will come to consensus on the cause of the fish kill.

Each group needs to turn in some information so that I can give you all some points for the work you have done. You will turn back in your folders with the following items:
1) The original data packet
2) All of your graphs
3) A copy of each persons current event
Please turn in these items only and in this order.

Presenting Areas of Expertise

For further information on possible causes of the fish kill, visit the following sites:

Lead in drinking water

Other heavy metals

Molecular substances

Non-point source pollution

Optimal pH for water quality

Dissolved oxygen

The Trouble With Cleaning Up

I'm still astounded that none of you in Period 2 have seen the movie Erin Brockovich! I do recommend it -- it is a nice Hollywood take on the very real problem of water pollution. As we discussed in class, at the end of the movie (and in real life) it seemed like everything was fixed -- PG & E paid the citizens of Hinkley over 330 million dollars in restitution. After paying out that much money, surely they would address the problem so they wouldn't have to pay money like that again! But, according to recent tests, the toxic hexavalent chromium plume has continued to spread. You can listen to another report on the continuing problem in Hinkley from NPR.

What is the take home message from all of this? It is alot easier to make a mess than it is to clean it up. Case in point -- those superfund sites we talked about last week. The industries responsible for polluting these sites were making profits while they made these messes. When it came to cleaning them up, though, not much could be done. So now they just sit there, all toxic and abandoned.

What will it take to prevent industries for polluting in the first place?

Researching An Element

Physical Science Students:

You may use the following resources to research your element:

The Visual Elements Periodic Table
This on-line and interactive periodic table gives a brief background on each element.

The Periodic Table of Videos
This website has short videos for each element on the periodic table. Their content varies, but often they do include the history of the element.

Interactive Periodic Table
This periodic table gives extensive information about the discovery of each element.