I I

and analogief edited by

RON DELORENZO Mlddle Georgia College

Cochran Georgta 31014

Be a Milllonaire-Get with the Action! Alvan D. Whlte Scnence Oepanmsnt Stockpon College of Technolagy Welt naton Roaa Soum. Stocloorl

When talking about the distribution of molecular velocities, we can use money as the analogy. Thus, the distrihution of molecular velocities is like the distrihution of wealth among people. Each financial transaction results in either a gain or a loss as far as any individual is concerned. A series of gains and you could end up a millionaire, a series of losses and you're on skid row. Each transaction is likened to a collision between molecules with a resulting gain or loss in energy and hence velocity. There will also be a continual change in velocity (see how your hank balance jumps up and down!).

If you become a millionaire, you have the necessary funds to be "where the action is." In the same way, if a molecule has a very high velocity it may have sufficient energy to overcome the activation energy barrier and react.

One can also note that during a hoom time (increase in temperature), the average amount of money per person in- creases, in a recession it decreases. And it is probably true to say that during a hoom there is also a greater proportional increase in the number of millionaires than in the average amount of money per person.

Let's Get the Heck Out of Here! Alvan D. Whlle S ~ O C ~ ~ College of Tecnno 0%

Well~ngton Roaa So.th. Stocrpon Chesnue SKI 3-0 tJr(

The importance of the rate-deterrniningstep in a chemical reaction is often referred to as the "bottleneck ~ r i n c i ~ l e . " I -~~~~ ~

like to use the analogy of a football stadium. Imagine it to he filled with 80.000 snectators. Suddenlv there's a warnine that a bomb has been planted. Unfortunately only one single turnstile is workine. Peoole can run about in ~ a n i c a t high speed inside the ground and across the playing area, and in the streets outside. hut the rate a t which the stadium empties must he equal to the rate a t which they can get out thrbugh the turnstile.

Oxidation and Reduction Alvan D. Whlte Stockport College ol Technolagy Wellington Road South, Stockparl Cheshire SK1 3UQ UK

One of the problems often encountered in teaching oxida- tion-reduction is trying to get across the idea that during a

redox reaction it is the oxidizing agent that is reduced and it is the reducing agent that gets oxidized. A simple analogy is to use a bottle of some suitable heverage (milk, Cokem, beer etc.) and a small glass. As you pour from the bottle into the glass, the bottle which is the filler gets emptied while the glass which is the e m p t w gets filled.

Entropy Rules in My Class Too! Alvan D. White SIOC~PO~ CO ege ot Tecnno og) Welltngtan Roao SoJth. Slochpon Cneshlre SKI 3-0 UK

The concept of entropy is often introduced via the degree of disorder. This is then linked to the probability of a mi- crostate. I t may he better, however, to approach the ideas of entropy, order, and probability on the macro scale by asking how many memhers of the class possess a pair of blue jeans. This is almost invariably everyone. Next we discover whoowns a white shirt or hlouse. Again this will he everybody. From this we can see that, if the class is given a free choice as to what to wear, it is possible for me to come into class and find everyone dressed alike. As any teacher will know, this situation of high order (low entropy) is highly unlikely, or of low prohability. On the other hand, the more disordered, non-uniform array I usually find myself facing is the most probable one. This is the one we call the equilibrium state.

Pushing the analogy a little further, it is clear that a highly ordered state is obtained only if work is done on the system, i.e., if a rule on dress for class is imposed by the school/college authorities or if someone organizes everyone (teacher in- cluded) to turn up dressed alike

1 This feature presents a coilection o scriplive applications and analogies signed to help students understand son me dinicun conce~ts heouentiv encwnl in chemistry. ~onirlbutions m i l will pro a greater appreciation and knowledge c lltical, religious. economic. historical scientific aspects of life are encouraged.

Ron DsLorsnra is an Associate Pro- fessor in the Deparlment of Chemistry at Middle Gecrgia College. He is also Campus Cwdinatw for the computing facilities and teaches an ergirering cwrse in FORTRAN. He received his BS from St. John's Univer- sity In 1963 an6 the MS and PhD in Physi- cai-Inorganic Chemistry from Lowell Tech- nolwical Institute in 1967 and 1970. resoectivelv. ~ ~ 0

h. DeLwenm is very interested inrelaiing course material to the real waid. He has just cmpieted a text entiled "Problem Solving in General Chemistry" published by D.C. Heath and Company which emphasizes his applications and analogies approach in teaching.

Volume 58 Number 8 August 1981 645