A Table Tale

(The following piece was first posted on www.chemicalsareyourfriends.com, to which I am now contributing my thoughts on Chemistry. I will, however, keep on posting stuff which is not strictly chemistry here, in addition to mirroring my writing on Chemistry)


It is merely a table. Or is it.... I first heard Tom Lehrer sing "The Elements" song when I was taking my first year general chemistry course more than a decade ago.

 

 The song lists all the elements known at the time, which was only 102, compared to the 114 officially recognized elements we have today, all sang to the tune of Gilbert and Sullivan's Major-General's song. The final words of the song are:

"These are the only ones of which the news has come to Harvard,

And there may be many others, but they haven't been discahvahd"

And here lies the true wonder of the graphical masterpiece commonly known as "The Periodic Table of the Elements". Its name is misleading, since by the use of the word 'table' one may expect nothing more than "an orderly arrangement of data". But the periodic table is actually something completely different.

It is ... (wait for it, building the suspense here) .... A GRAPH!!!!
Or more precisely, an amalgamation of many graphs!!!
Yes, that's the truth.

What is the difference you may ask?
Well, a table is usually a way of presenting information in a tidy fashion to make it easier to find specific information of relevance. But a graph is a much more powerful tool. A graph plots values that are correlated to two or more attributes. Once plotted, trends can sometimes be observed. And if a trend exists - you can PREDICT! After all, science is more than just observing nature and taking notes. Science is about using the earlier observations in order to predict the outcome of future experiments (aka forming hypotheses)!
When Dimitri Ivanovich Mendeleev first published his periodic table of the elements in 1869, the elements were (for the most part) arranged based on their molecular weights. Mendeleev noticed that when arranging the elements according to their molecular weights (since atomic numbers were not yet a measurable quantity at that time - see footnote), you can arrange the elements in such a way that certain periodicities arise with respect to the properties of the elements. But the true breakthrough in Mendeleev's approach was that he then utilized his discovered pattern to predict new elements which had not yet been discovered. By using the periodic trends in the properties of the elements, he was able to predict some of the properties of those yet-to-be-discovered elements. And guess what ... he was right. Shortly after, Gallium, Scandium and Germanium were discovered, corroborating Mendeleev's hypothesis and exemplifying the practicality of the periodic table of the elements.

 I mentioned the word "periodicity" several times, but periodicity of what? The answers is: quite a fair bit. Let's look at how the Ionization energy of the various elements changes when ordered in the periodic table arrangement. (The ionization energy is the amount of energy needed to separate one electron from the initially neutral atom). In the above graph, the height of each element corresponds to its first ionization energy (in eV units). So what can we tell by looking at the graph? The first obvious observation is that when moving down each column, the height decreases (granted there are some exceptions, but let's look at the general rule). Another observation is that when moving from left to right along each row, the height generally increases, although several sharp drops are seen (such as in the case of N-nitrogen and O-oxygen or Cd-cadmium and In-indium). You can check out some more examples at www.chemicool.com . Atomic radius, ionization energy, melting point, boiling point, density; they all show a periodic behavior when plotted against their atomic numbers (again see footnote). Why do we get such periodicities you might be wondering? The atomic number, the number of protons in the nucleus of the element, provides the basis of the periodicities in the periodic table. The more protons there are , the heavier the atom is. Additionally, the atomic number also indicates the number of electrons around the nucleus (since the atoms in their pure state are neutral, therefore for every positively charged proton in the nucleus there will be a negatively charged electron around it). As the number of electrons increases, the atomic radius becomes larger (with exception of 'kinks' due to periodic changes in the arrangement of the electrons, similar to the sudden sharp drops we saw for the ionization energies). And since electrons are the main players in chemical reactions, the number of electrons and their specific arrangement around the nucleus will affect the reactivity of the element. In chemistry, electrons like to be paired. Just like people (nudge, nudge, wink, wink). Let's take a look at the group with a common attribute along a vertical line in the periodic table: Lithium, Sodium and Potassium. They all have a single unpaired electron, and are similarly reactive because an unpaired electron is more reactive being all by itself.
Contrary to the above group of elements, Helium, Neon and Argon have all their electrons paired. They are all similarly nonreactive and belong to the same group along a vertical line in the periodic table. (In fact, the electronic structure is more complicated than simple pairing, which is why we saw fluctuations in the above graph where the ionization energy showed sharp drops in the general increasing trend moving from left to right along the rows. Since this post is getting quite long, I'll leave such descriptions to another time) The periodic 'table' contains a plethora of information. Graphically, it is (probably) the most concise form to summarize an astounding amount of information.
 So next time you gaze at the periodic table, remember, it is more than 'just' a table. It is the essence of the chemistry that makes up our entire universe!


 Footnote: The numbers we see today as the basic ordering of the elements are the Atomic Numbers. These are the number of protons in the nucleus of each of the elements, but they were only discovered in 1913 by Henry Moseley, which makes Mendeleev's accomplishment even more impressive.

Science Fair at the Science Camp

Wow, it is sooooo hot and humid these days in Toronto.

And like every summer, Toronto is bustling with tourists.
But more than that, Toronto is a popular place for people from all over the world to come and improve their English skills, while soaking up sun and sites of this gorgeous place.

How does that have anything to do with science?
Well, as it happens, this last Saturday, as part of the Pueblo Science experience, we held a "Science Fair" event for the CISS ESL camp at St. Michael's University.

We had a GREAT time!!!!

We had:

Balloons pushed into Liquid Nitrogen

What you see:
When an inflated balloon is pushed into liquid nitrogen it shrinks.
When taking it out of the liquid nitrogen, it expands back to its former size.

Why does that happen?
That's because the trapped air inside shrinks when the temperatures drop, and expands when the temperature increases.
The pressure inside is always constant at 1atm, same as in the atmosphere.
The amount of air molecules which are mainly nitrogen molecules and oxygen molecules is kept fixed because the balloon is closed tight.
The only two variables left to be changed are the temperature (liquid nitrogen is at -196 centigrade!) and the volume.
The relation between all these attributes (pressure, volume, amount and temperature) is called:
The Ideal Gas Law, which is P*V = n*R*T
(P is the pressure,
V is the volume
n is the amount of molecules
T is the temperature
and R is a constant that relates all of the above to one another and is called not surprisingly - the gas constant) 

 

We also had:

The Disappearing Vial

 What you see:

When you submerge a glass vial into a glass filled with oil, the vial becomes invisible!!!!!!

Why does this happen?

The reason we can see things is because light hits them, bounces back, and hits our eyes.

But the medium around the object also plays a role.

For instance, we look at a coin on the table, it is easy to see it and grab it.

But when the coin is in a pool of water, we see it, but have a herder time grabbing it.

This is because the water bends the light as it penetrates it. This bending of light is called REFRACTION, and the extent by which light is refracted is called "Refractive Index"

When light passed from one medium (say water) to another medium (say glass) the light will bend if the refractive indexes are not the same. 

BUT, if the refractive indexes are the same (like in our case with oil and glass), then light passes through without bending (or, refracting) going straight through. This makes the glass appear invisible!

 

 

 And also:

Non-Newtonian Fluid

 What you see:
When you mix corn starch and water, you get a gooey mixture (very slimy).
When you push your finger in it slowly, it goes all the way in.
When you pound it hard and fast, it cannot penetrate. The mixture appears 'solid'.

Why does that happen?
Newton was able to formulate how fluids behave by stating that when you apply a force on them, the fluid will flow. But like all motion, fluids experience "friction" which is referred to as viscosity.
What Newton saw was that viscosity was constant of the material, and only changed with temperature.
However, some fluids (like our corn starch) behave differently. (therefore the term - "non-Newtonian")
Our stuff 'solidifies' with strong force, meaning its viscosity increases with force.
When the force is weak, the viscosity is lower.

There were a few more activities, but I think this post is long enough.
I'll continue this another time.
Stay tuned....

Misleading titles - real science, false impression

Science breakthroughs are exciting. They change our lives, they hold the promise for a better world.
Sometimes the explanation is straight forward, and can be easily understood by most people, even if they don't have any related background.

But sometimes, in the process of trying to convey breakthrough research to the ordinary person, editors (or bloggers, or twitters, or facebookers or .....) pick up on a concept they know about (even partially) and use that as the "catch", the title that will make people want to read the article/watch the video.

The problem?

Creating a false notion in people's perception. Misleading them to think something which is (scientifically speaking) is not true.

Today's example (and there are examples like this one popping out too often than one would like to admit):

"Doctors Take A Long Shot And Inject HIV Into Dying Girl. The Reason Why Will Amaze You."

But the real science is more subtle than that, as carefully outlined by Cancer Research UK:
http://scienceblog.cancerresearchuk.org/2013/06/25/no-doctors-did-not-inject-hiv-into-a-dying-girl-to-treat-her-cancer/

Their most important message to the public is:
"To be absolutely clear, the doctors in the video did NOT inject HIV – nor a “deadly disease” – into a child."

The reason for the misleading title is pinned to the fact that:
"According to the video ... the virus used in these experiments was originally derived from HIV, ... However, the virus has undergone significant genetic tinkering, meaning that it is no longer harmful ... And it’s arguable whether it should even be referred to as HIV at all, given how much it has been altered."

What really happened was that the HIV was used to alter the patient's own immune cells, to allow them to "infect" the rest of the body's immune cells with a new genetic trait (the one that kills the cancer cells).


Perhaps one can be forgiving, saying "but you admit that they used HIV, so what's all the fuss?"
The problem is that with such a title, people get the impression that HIV was the cure, where is fact, it was simply a "tool" to reprogram the body's immune cells.

Would you believe me if I told you I painted my house with Acetone? you would think this is odd.
But if I used Acetone as a paint thinner, and painted my house with the "modified" paint, you would naturally say that claiming I painted my house with Acetone is misleading. Yes, Acetone was part of the paint, but saying I painted with Acetone gives you the wrong impression.
Exactly like the story of the HIV and cancer cure. 

Words are powerful.
Use them wisely.

Distillations

I just received the University of Toronto CHEMISTRY ALUMNI MAGAZINE called DISTILLATIONS.

I was honored to be included in the "Graduate Profiles" for this addition

as well as mentioning the work Pueblo Science does, promoting science literacy

I want to take the opportunity to personally thank Penny and Nina from the Chemistry Department for their constant support, and for the wonderful job they are doing.

Pool party gone scientifically wrong

Can liquid nitrogen react with the hypochloric acid in the swimming pool (which is the chemical form in which we use chlorine in pool water)?

Some people seems to think so.... and newspapers seem to publish this nonsense:

http://www.news.com.au/world-news/liquid-nitrogen-stunt-at-jagermeister-party-in-mexico-leaves-a-man-in-coma/story-fndir2ev-1226666959021

Lets get the fact right this time:

Nitrogen, in our case is the molecular form of nitrogen N-N or N2 (as opposed to the Nitrogen atom) is found in our atmosphere as gas, and accounts for about 78% (source: http://www.space.com/17683-earth-atmosphere.html). Thanks to technological innovations we can now make Liquid Nitrogen (http://blogs.howstuffworks.com/2009/07/27/how-do-they-make-liquid-nitrogen/)/

The boiling temperature of liquid nitrogen is -196 centigrade. When it comes into contact with the water in the pool (roughly room temperature, say 25 degrees) it will boil pretty fast, creating lots of gaseous nitrogen. The nitrogen gas is still very cold and therefore cools the air around it. With all the humidity around (humidity is a measure of how much water molecules are in the air), the water condenses into droplets, just as if we were high up in the sky where its pretty cold. This is why you see all those clouds in the picture.

Here's what I had the pleasure of doing with liquid nitrogen:

So far it seems pretty harmless. HOWEVER... if the amount of nitrogen is so large, than it will displace (push) the air around the pool, which means that the people in the pool will have less oxygen to breathe, and are likely to pass out/go into a comma/die/drown....you get the point. The bottom line is that the danger is asphyxiation and not poisoning (as suggested in the article)

The moral of the story is that never stay in the pool when liquid nitrogen is thrown in. Outside is better, and be sure that this is an open space.

What about the chlorine you're wondering? Its still in the water. Nothing bad happened to it. Thanks for asking.



I would like to see more newspapers talk to actual chemists before printing such comments within their published work in the future. Save us a lot of headache explaining why the journalists got it wrong.

Science to toy around with

I would like to introduce you to Slater Harrison from Pennsylvania in the US.
He's a science teacher, but even more so, he's a science lover.
How can I tell (since I have never met him in person)?
He has the most amazing website called:

Science Toy Maker

(http://www.sciencetoymaker.org/)

and what is the website all about? well.. its about science, but in a way which I relate on a personal level with my work with Pueblo Science. The website aims to do the following:

"All science toys and projects:

• *are accessible (so cheap to make that nobody is excluded because of cost, and they don't require special skills, tools, materials, or work facilities beyond a kitchen).
• *have a "more about" page with explanations, historical context, related activities and high quality links for further research.
• *have clear step by step video directions or text instructions with lots of pictures."

You see, Slater provides opportunity, not products. He provides knowledge, not withhold it. He provides tools for everyone who wishes to experience, enrich, experiment, and just want to have fun with the world we see around us.

And thanks to his work, I too had the opportunity to try my hands on flying one of his  air surfers (the one called the "Spinny Bug"), together with my 6 years old daughter. Before I start the description, I can tell you that she had lots of fun making it and trying to fly it (although both of us need lots of practice).

SO here's what we did:

1. Start by cutting out the pattern

2. Tape the pattern on the 0.5mm thick foam (which you can get from Slater)

3. Cut along the middle line to get two gliders:

4. Cut along the middle line again to get the two halves of the glider

 5. Cut the extra bits on the ends (which will separate the pattern paper from the foam)

6. Fold each piece into half

7. Tape two folded pieces together, and you've got the glider

8. Let's go fly a glider

9. I got to try that too (I tried posting the video, but it didn't work. I'll try tomorrow)

Now I should point out that there are a lot more details and explanations on Slater's website, which is why I'm not taking the time repeating them here (there's enough redundancy on the internet already). So just go to http://www.sciencetoymaker.org/ and check it out, you won't regret it. What I can say is that the written explanations are accompanied by a video, narrated by Slater (with a lovely voice I must say). The video is done so well, that she could follow the instructions after just one viewing.

Thank you Slater for lots of great ideas, and I know I'll be enjoying more of them in the future.

Chemicals Have Feelings Too!

I've recently wrote a blog post for my good friend Dorea, to post on her beautiful website
Chemicals Are Your Friends!

She got Mike Ellis to create amazing pictures to complement the text, and with skill and imagination, Mike has done superbly (I wish I could draw this good).

I won't copy and paste the blog here, cause you can just follow the link:
http://chemicalsareyourfriends.com/sliders/chemicals-have-feelings-too/

Enjoy