用草猛做rate of respiration的實驗的step

First, you use dropper to take about 5 cm cube hydrogencarbonate indicator into a test tube. Then, put a small wire gauza into the test tube just above the indicator. Next, put one or two 草猛 into the test tube and enclose the test tube by the stopper. Finally, you observed the colour change of the hydrogencarbonate indicator and take record.