(2009? Model No.2 in Minhang District) Two students, A and B, respectively used aluminum blocks and water to explore the relationship between mass and volume of matter. A student uses a balance and a measuring cylinder. (1) According to classmate A's record on the draft paper, we can know that the mass of the metal blocks in his three experiments is 27g, 54g and 8 1g respectively. According to the volume of 40ml water and the corresponding 50ml, 60ml and 70ml below, the volume is 10ml, 20ml and 30ml. , respectively. See the following table: experimental serial number: metal mass (g) metal volume (ml)127102542038130 (.

So the answer is: the mass of aluminum block is directly proportional to its volume.

(3) Comparing the data (1), (2) and (3) in Table 2 of Student B, it can be seen that the measurement of water quality is obviously wrong, because he "measured their total mass after adding water into the beaker, and then measured the volume of water with a measuring cylinder", so it is very likely that the total mass did not subtract the mass of the beaker, leading to the incorrect experimental conclusion.

So the answer is: Student B made mistakes in the experiment, and the water quality measurement was wrong, and the total mass did not subtract the mass of the beaker, which led to the incorrect experimental conclusion.