Procedures*

1)Parepare 3 flowers and 3 plastic bags and label the flowers as'A','B','C', and some incense.

2)Put 3 flowers at the same place. For example, balcony.

3)First, use the colorless plastic bag to cover flowerA. Put two incense sticks near the flower. Also burn it in the morning every day.

4)Second, put a colorless plastic bag cover flowerB too. Put one incense stick near the flower. Also burn it in the morning every day.

5)Finally, put a colorless plastic bag cover flowerC too. Put one incense stick near the flower. But no need to burn it. It's because we need to control experiment.

6)Repeat step 3 to 5                            for one week.