Saturday, 14 March 2015

Diffusion ISA Ideas for AQA

One way of doing this experiment is to add a crystal of KMnO4 to a large beaker containing 1 litre of water and waiting. In the images the breaker on the right was at 65C and the one on the left at 12.9C.

A small crystal of KMnO4 was dropped into the beaker and left for a short time.

The only problem with this experiment is that it is very difficult to quantify the rate of diffusion, so we are going to modify this experiment and use a colorimeter instead.

The better alternative.#
We used a colorimeter with pasco Sparkview software to observe the rate of diffusion.
A small crystal ( just under the cuvette in the picture) was placed into the cuvette and added to the colorimerer which recorded the results.

Measuring the green absorbance the graph above was produced as the KMnO4 cystal dissolved and spread throughout the hot water.

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