The Art of Chemistry: Making and Shaping Molecules
Dr Paul Evans from the UCD School of Chemistry and Chemical Biology began his talk, The Art of Chemistry: Making and Shaping Molecules, with a demonstration of the oscillating iodine clock. By mixing three solutions together he initiated a chemical reaction that the students were able to monitor by the colour change which went back and forth between black and colourless.
“The periodic table is the basis of everything in the world, according to chemists,” explained Dr Paul Evans. “However, 95% of the world is made up of about 20 of the 117 elements.”
The secondary school audience watched a video of the Chemistry Element song by Tom Lehrer which gave them a whistle stop tour of the periodic table. To demonstrate how atoms combine to form molecules Dr Evans asked the audience to join hands to form three molecules made up of people. He then explained how the scale of molecules is so small that in one pill there are roughly one billion (1000 million) more molecules than people on the planet!
Dr Evans also talked about some of the applications of chemistry in medicines, electronics and textiles. The students were fascinated to learn about the Speedo swimming suit worn during the 2004 Olympics, made from a fabric designed to mimic the scales of a shark.
“There is lots of asymmetry in nature,” continued Dr Evans. “For example, our right and left hands are mirror images of each other but you can’t superimpose one hand on top of the other. In my research I study asymmetric molecules. They have the exact same number of elements such as carbon, oxygen and hydrogen but are arranged differently.”
Two volunteers were then called on to examine samples of a naturally occurring substance called carvone. One vial contained the “right-handed” carvone and the other contained the “left-handed” carvone. The students found it hard to believe that one smelled like spearmint and the other of caraway seeds even though they were composed of the same number of carbon, hydrogen and oxygen atoms.
“In chemistry as long as you stick to some basic rules, you can make what you want and create something new – just like art,” concluded Dr Evans.
