Today, Thursday the 20th of October, we worked in two groups: Lemin and I worked in the lab and started about 8 reactions and filmed them and Max and Heleen prepared the video footage of the reaction and made 3D-models with it.
We interacted with the reactions in multiple ways:
- We added more of solution B
- We added more of solution C
- We added drops of solution A
When we added more of solution B, we found that the solution in the petridish became very grainy. Because this precipitation made it very difficult to obtain clear footage, we quickly decided to stop the reaction and throw it away.
Adding more of solution C to the reaction slowed the process down a lot. We had to swish the solution for a long time before it turned blue and red and the typical blue rings only started to form after about 10 minutes.
Adding drops of solution A to the reaction formed blue rings in that spot: this is exactly what we had tried to achieve multiple times before. With this information, from now on we can start reactions in every place we want and influence the reaction in such a way that we can make more or less rings appear in the wanted locations. In the pictures below you can see very clearly where we added drops of solution A to the reaction.
Tuesday the 18th we also did some small experiments. For instance, we wanted to see if the depth of the petridish had any influence on the reaction. We thermoformed a ‘dish’ with multiple bumps with different depths and started a reaction in it. The results were not of any significance, as the solution became too dark to see through and too chaotic. In addition to this, the acid started to bite through the plastic of the dish. In the picture below it is visible that this experiment was not successfull.
In the table below you can see our other findings:
|What did we change?||What kind of pattern forms?||Why does it work or not?||Are we going to use this?|
|Warmth||–||Too difficult to realize||No|
|Light||–||The difference in warmth has little to no effect on the speed of reaction.||No|
|Touching||By touching it one time spirals are formed. By making a line the reaction becomes red without any blue circles.||Too difficult to control||No|
|Depth of dish||Not visible||Can not be filmed as no light travels through the dish.||No|
|Add indicator||The added indicator forms a red drop. It turns blue and red respectively and slowly takes over the underlying pattern.||Too much contrast between indicator and underlying pattern.||No|
|Add solution A||An oscillating blue pattern starts at the spot A was added.||We can decide where a reaction starts.||Yes|
|Add solution B||The existing solution is separated by a green/yellow liquid that sticks to the petri dish||The reaction stops.||No|
|Adding coloured reaction (with indicator) to see-through reaction (without indicator)||The oscillating pattern slowly spreads from the red dot. The contrast is worse than what is normally the case.||A small part of the indicator is added to a reaction that has already started. This is already mixed and thus reacts faster with the see-through liquid.||Maybe|