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Oscillating reactions The first thing I had to do was to find an oscillating reaction recipe. It was my teacher who gave me the first document about those reactions where there was an oscillating reaction recipe but not the BZ one; we had agreed that we would study BZ reaction so I searched for this last one on the net and I worked with it in all my experiments except for the concentration and ion change experiments which are related later. First of all I have to say that in the original recipe there is ten times more of each product than the one I have used (except in the case of solution C that I shall explain later) The first reaction I did was intensely red colored, and it had a much longer oscillating period than the other reactions I would do in the next experiments. I have to say that I did not control all the parameters, but what is interesting is that the initial period was the longest I would ever see. In the second experiment I tried to reproduce the first one but more accurately. In the next experiment I did, my intention was to discover the effects that the temperature could produce on the reaction. As a conclusion to this experiment I can say that the hotter the reaction is, the shorter the periods are. I began to experiment if light affects the reaction behavior. This was the most difficult part of the investigation because it was very difficult for me to isolate this parameter. After some experiments I realized the influence that the speed of the stirring plate had. However, another problem arose: the temperature. The light I used gave too much heat, so that the temperature of the solution raised up quickly, therefore there were two variables in play still. After some thought I realized that the variation of the periods in the same reaction process interfered with the action of the light. Solved all these problems I observed oscillations between illuminated and non illuminated solutions. As a conclusion to this experiment I can say that the more illuminated the reaction is, the longer the periods are. In another experiment, I tried to identify the influence of the stirring plate mixing speed in the reaction. I carried out this experiment simultaneously with some light experiments because it was then when I realized that this could be another variable parameter. As a conclusion to these experiments in mixing speed I can affirm that the lower the mixing speed is the shorter the periods are, although without mixing speed the oscillations do not appear. Other conclusions are not so clear but it seems that a high mixing speed makes the reaction turn irregular. In another experiment I just left a few ml of the solution on a Petry dish and I observed that it did not oscillate in the way I had seen before. Instead, some blue circles that increased their radium and joined up appeared from some characteristic points. I looked for some explanation and I found that in fact I was faced with chemical waves due to concentration changes along the space. Concentration influence and ion exchange experiments were also made.
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