The Mysterious Mentos and Coke Geyser

Since the You Tube video of Mentos and diet coke went viral, everyone knows what happens when you combine these two tasty treats, but not everyone knows why they create a exploding geyser of foam. Leave it to the scientists at MythBusters to come up with a good theory about why this happens and to design a good test.



How did the guys at MythBusters use the scientific method to test their theory about the reaction of Mentos and Diet Coke? What experiment would you design to further explain the reason behind this reaction?

Thermite and Liquid Nitrogen

What happens when you take the most exothermic reaction you can think of and dunk it in the coldest thing you can think of?

On Friday we saw a thermite reaction. We noticed how extremely exothermic it was -- it gave off an intense amount of heat and light. Would you be able to quench a reaction like that with something incredibly cold, like liquid nitrogen? That is the kind of question that good scientists ask.



What questions do you have about the reactions we've seen?

Thermite!

Since it is Friday, today is a good day to explore the classic exothermic reaction of thermite. Thermite is a mixture of iron oxide and aluminum. When ignited, it undergoes a vigorous single-replacement reaction. Use the metal activity series to explain why the reaction is so vigorous. You can also propose the equation that describes this reaction.



Another interesting facet to explore is thermite's role in the Hindenberg explosion.

Potassium Chlorate and Sucrose

Here is another example of an exothermic reaction. This reaction is actually two steps. First, the decomposition of the potassium chlorate, which creates oxygen. The oxygen in turn fuels the combustion of sucrose.



Can you predict the two equations happening here? You might need to do some research to figure out the formula for potassium chlorate and sucrose.

A Reaction a Day...

...Makes the Chemistry Blues Go Away!

Ever true to my word, I want to prove that Chapter 11: Chemical Reactions, is one of the most exciting chapters in chemistry. The only limitation to this is that some of the coolest reactions are slightly dangerous and we don't have the proper facilities to demonstrate them in. But, with the magic of the internet we can observe them anyway. For the rest of the chapter, I will post a daily, amazing reaction on the blog.

Today's reaction is the reaction between sodium and chlorine gas. Can you predict the equation that describes this reaction?



Notice that this reaction is extremely exothermic, it gives off lots of energy. Why might that be the case?

Everybody Loves Avogadro

There's something about 6.02 x 10^23 that makes people whimsical. Maybe it's because of its funny name -- Avogadro's number. Or maybe it's because it is such an unbelieveably vast number. Or maybe it's because we call it a mole, which brings to mid furry cartoon animals with glasses. But whatever it is, it certainly brings out the fun side of chemists. What chemist doesn't celebrate Mole Day, from 6:02 am to 6:02 pm on October 23? Mole Day is a great day to tell some mole jokes.

Q: What do you get when you have a bunch of moles acting like idiots?
A: A bunch of moleasses.

And who's the man behind the name (which is avoGADro, not avocado)? Amadeo Avogadro was an Italian theoretician who did work with gases. The number, 6.02 x 10^23, was given his name many years later in honor of the work that he did regarding the gas laws; work that was never recognized while he was alive. So, though it bears his name, Avogadro had nothing to do with the mole. And while a mole isn't a fuzzy little animal, Avogadro also isn't a delicious green fruit.

But I think the real attraction of Avogadro's number is its hugeness. 6.02 x 10^23 is a truly large number. If you were to try to count to 6.02 x 10^23, starting with the number "one" at the rate of one count every second, it may take you about 1,909,577,942,668,696 years to finish. That is longer than our universe has even existed. If you spread Avogadro's number of unpopped popcorn kernels across the USA, the entire country would be covered in popcorn to a depth of over 9 miles. A mole of soft drink cans would cover the surface of the earth to a depth of over 200 miles. A mole of something is alot!

What fun facts can you find about Avogadro's number?

Scales, Of What?

Chapter 3 of Natalie Angier's The Canon, is called "Calibration: Playing With Scales" and is chock full of insight and observations related to how we measure the things in our world. These topics can be overwhelming and mind-boggling and to understand the chapter, we should start by understanding the chapter title. What is calibration and what does it have to do with measurement?

You've probably heard or used the word calibration in reference to the balances. I often ask you to check to be sure that they are calibrated. When I do, you look to see that when nothing is on the balance it reads zero. According to Wikipedia, (and yes, I am citing wikipedia, a thing I tell you never to do, but it just so happens, in this instance it gives a very good definition for calibration) calibration is:

"a comparison between measurements – one of known magnitude or correctness made or set with one device and another measurement made in as similar a way as possible with a second device. The device with the known or assigned correctness is called the standard. The second device is the unit under test (UUT), test instrument (TI), or any of several other names for the device being calibrated."

Calibration gives us a starting point or a point of comparison between measurements. We may have two different units of measurement calibrated to each other. This is where scales come in.

Angier is not talking about scales of a fish, or scales on a piano (although, scales on a piano are the same concept); she is talking about scales of reference or measurement of numbers. Something that is really tiny is on a small scale. Something that is really huge is on a large scale. All the metric conversions we have been doing are about changes of scale. Scientific notation provides a quick and easy way to change the scale of something.

OK, now that we have made sense of the title of the chapter, it is up to you to make sense of the rest of this. I invite you to post your thoughts.

Science in the Summer? Sure!

There are many wonderful summer science opportunities out there and this is the time of year when they begin accepting applications. Often these programs offer hands-on opportunities to do real science in the field. Whenever I read the descriptions I wish I was still in high school so that I could apply. Here is a sampling of some of the recent programs I have received information about:

The Huntsman Marine Science Center in St. Andrews, NB

In this program you will gain hands-on field experience collecting data for current research projects the scientists at Huntsman are working on.

The Ocean for Life Program

This program is a field research based program that is designed to inspire stewardship and a sense of interconnectedness and place. It focuses on ocean science, cultural sharing and youth media projects. (And if you get accepted, it is paid for.)

The Maine State Aquarium Junior Docent Program

For an experience a little closer to home, you can volunteer for the Maine State Aquarium. In this program you are trained to be a docent at the aquarium which means that you are the person interacting with the public, teaching them about the animals, facilitating use of the touch tank and helping out behind the scenes to feed and care for the animals.

Are you skeptical that being a research assistant during the summer won't really amount to much? Check out this story of a high school research assistant who helped a scientist make a big breakthrough in their research on North American mammals.

Scientist at Work: More Animals Found in Urban Forests

By ROLAND KAYS

Published: February 7, 2011

Camera traps show more and more varied animal life in suburbia than in wild forests.

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?