Requirements: 1 small beaker, 10 ml measuring cylinder, 5 test tubes, 1 Petri dish, 1 filter paper, stop-clock, 1-M sodium thiosulfate solution, 0,5-M nitric acid

Procedure:

With a pencil draw a small cross on the filter paper and put the Petri-dish upon it.
Start with 6 [ml] of the 1/6-M solution and give it into the Petri-dish.
Measure 6 ml of nitric acid (an excess of the acid).
Add it to the Petri-dish while starting the stop-clock at the moment of addition.
Shake slightly to mix the solutions.
Note the time taken for a precipitate of sulphur to appear so that you can't see the cross anymore.
Repeat the experiment with the other solutions in the same way and make sure you have the same degree of cloudiness to cover the cross.
Plot a graph of concentration of sodium thiosulfate against time for precipitation and a second graph of concentration against 1/time (which is equivalent to the speed of reaction!