Investigate how changing the concentration of sodium thiosulphate affects the rate of the reaction with hydrochloric acid

AIM

I aim to investigate how changing the concentration of sodium thiosulphate affects the rate of the reaction with hydrochloric acid.

The reaction

The reaction that will occur is a cross-drawn on a piece of paper disappearing because a precipitate (very fine solid) of sulphur is being produced as a waste product of the reaction.

FAIR TEST

The variables in this experiment are:

Concentration of sodium thiosulphate,
temperature of both liquids at start of experiment,

Temperature of room at start of experiment,

Volume of hydrochloric acid,

Volume of sodium thiosulphate,

The variable I will be changing in this experiment will be the concentration of sodium thiosulphate and I will be keeping all of the others which I mentioned the same.

I will do my best to control the variables by using the same bottle of sodium thiosulphate I will use the same equipment as much as possible and will control the temperatures of everything ...