Coloring Chemistry?

We recently did a lab in chemistry class were we looked at metal salts and figured out what color they were. Looking into it, I found something equally as awesome. That’s right: chemistry labels for crayons! For each Crayola color, there is a chemical equation for it that sticks right on over the color’s wrapper. It matches the wrapper color, so it looks like it is not even there!

crayola-chemistry.jpg How cool is that?

It is actually quite hot. Why? Because these chemical formulas are not actually in the crayon, they just create the same color when they are burned. These chemicals burn a certain color due to the electrons. The electrons in the metal salt start off at different energy levels. When they are heated up,  they move around faster and more randomly. In one article, the writer put it this way. The flame “supplies thermal energy to the atoms and molecules of the substance, promoting electrons from a ground (lower) energy state to an excited (higher) energy state.” In simpler terms, heat transfers energy to atoms, which cause the electrons within the atom to go from little energy to a lot of energy. Another great explanation that easily explains the colors is also found on the site. ” In simplest terms, when the wavelength is long, the energy is small, and conversely, short wavelengths mean higher energies. Applied to photons emitted during electronic transitions, an electron dropping back to ground level from a very high excited energy state can give off a photon of relatively short wavelength such as blue or even ultraviolet light. Similarly, a small difference in transition energy levels could give rise only to the emission of a relatively long-wavelength photon, such as red light.” In other words,

Long wavelengths = small energy = big difference in energy = blue or ultraviolet light.

Small wavelengths = big energy = small change in energy = red light.

There is much more information with much more detail on the site, and I would highly recommend reading it. The link is the last one below.

There is so much to learn, and I did not truly understand the whole idea as energy as a wavelength. Now I understand that the size of the wavelength determines the properties, and that it can tell you a lot about a substance from looking at it. By applying heat to a certain substance, you can learn more about the different colors, and about what makes that happen!

Links:

http://www.geekologie.com/2010/08/crayola-chemistry-the-chemical.php

http://www.accessscience.com/studycenter.aspx?main=17&questionID=4738

***BONUS: an awesome YouTube song about colors! http://www.youtube.com/watch?v=pWlukTTVavg Enjoy!***

So Ta Ta for now and hope to see your chemical reaction soon!

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