Research Project
A major difference between the DIY kit and the display version is the use of an alcohol reservoir instead of soaking felt stuck to the sides. When running a chamber for so long it is more convenient to use a reservoir that can hold a lot of alcohol than to have the equivalent amount of felt.
When the reservoir was used without heating, no mist was produced. This meant that the heating (here supplied by a heating wire connected to a power supply and laid in the reservoir) was compensating for the lack of surface area for the alcohol to evaporate from. From this came the idea (for the DIY kit) of spreading the alcohol on the felt as much as possible - this was highly succesful. Previously the alcohol was poured in to the top of the felt, with the expectation that it would drip down to spread. Instead a pipette was used to spread it around evenly and the results were very good. Spraying on the alcohol was tried but was unsucessful. Not only did it take a long time to get enough alcohol out, it evaporated too quickly since it was such a fine spray.
The reservoir was heated with a slowly increasing temperature. It was quite noticeable when the alcohol was too hot as convection currents became visible in the mist and the mist appeared at the top of the chamber. This is undesirable; the mist should appear mainly at the base. It was also apparent that the optimum temperature of the alcohol lay within quite a narrow range. For the size of chamber being used, it was found to be between 47-50ºC. This was a good starting point for working with the final chamber.
When the reservoir was used without heating, no mist was produced. This meant that the heating (here supplied by a heating wire connected to a power supply and laid in the reservoir) was compensating for the lack of surface area for the alcohol to evaporate from. From this came the idea (for the DIY kit) of spreading the alcohol on the felt as much as possible - this was highly succesful. Previously the alcohol was poured in to the top of the felt, with the expectation that it would drip down to spread. Instead a pipette was used to spread it around evenly and the results were very good. Spraying on the alcohol was tried but was unsucessful. Not only did it take a long time to get enough alcohol out, it evaporated too quickly since it was such a fine spray.
The reservoir was heated with a slowly increasing temperature. It was quite noticeable when the alcohol was too hot as convection currents became visible in the mist and the mist appeared at the top of the chamber. This is undesirable; the mist should appear mainly at the base. It was also apparent that the optimum temperature of the alcohol lay within quite a narrow range. For the size of chamber being used, it was found to be between 47-50ºC. This was a good starting point for working with the final chamber.
The Display Chamber - Alcohol Reservoir
