Required practical to mesure temperature change?

1)Add 50cm3 sodium thiosulphate soloutuion to conical flask 2)Mesure initial temperature 3)Place conical flask on paper with black cross 4)Add 10cm3 dilute hydrochloric acid to the conical flask start stopwatch 5)When black cross is no longer visible record the time on the stopwatch 6)Record temperature of reaction mixture 7)Clean aparatus and repeat with different temperatures of thiosulphate