1．可燃物燃烧的条件例1图甲和图乙所示实验方法均可用来探究可燃物燃烧的条件．(1)某同学用图甲所示装置进行实验,观察到的现象是_____．(2)另一同学用图乙所示装置进行实验．得到以下实验事实．①不通空气时,冷水中的白磷不燃烧．②通空气时,冷水中的白磷不燃烧．③不通空气时,热水中的白磷不燃烧．④通空气时,热水中的白磷燃烧．该实验中,能证明可燃物通常需要接触空气才能燃烧的实验事实是 1. Combustion Combustion Conditions Example 1 The experimental methods shown in Figure A and Figure B can be used to explore the conditions for combustible combustion. (1) Some students experimented with the device shown in Figure A. The observed phenomenon was _____. (2) Another classmate experimented with the device shown in figure B. Get the following experimental facts. 1 When no air is available, white phosphorous does not burn in cold water. 2. When the air passes through, the white phosphorus in the cold water does not burn. 3 When the air is blocked, white phosphorus in the hot water does not burn. 4 When the air passes, the white phosphorus in the hot water burns. In this experiment, the experimental fact that can prove that combustibles usually need to contact air to burn is