(2) Read the picture carefully, and the bubbles in the thermometer hit the bottom of the beaker, which is not allowed.
(3) In the process of rising, the bubbles in A gradually become larger, so it is a phenomenon during boiling, while the bubbles in B become smaller, which is a phenomenon before boiling.
(4) According to the common sense of life, if the heater remains unchanged, reducing the water quality can make the water boil as soon as possible; It can also be heated by a high-power heater. Prevent the water from transferring heat, and make the water boil as soon as possible. To sum up, the specific methods are: reducing the quality of water in the beaker or increasing the flame of alcohol lamp, or adding a lid to the beaker.
Because the beaker is used, it is heated evenly with asbestos mesh.
(5) A. As can be seen from the data in the table, water begins to boil in the 5th minute, and the temperature should be kept constant during the boiling process. However, at the 7th minute, the water temperature was on the high side, so the data at the 7th minute was obviously wrong, because the reading was inaccurate, which led to errors.
B, from the data in the table, we can know the characteristics of water boiling: continue to absorb heat, but the temperature remains unchanged;
C, according to the data in the table, the boiling point of water is 98℃; Because the boiling point of water at standard pressure is 100℃, the boiling point is 98℃, which may be that the pressure at that time was less than 1 standard pressure.
D, trace the points according to the data in the table and connect them with smooth curves.
So the answer is: (1) b;
(2) the bubble of the thermometer contacts the bottom of the beaker;
(3) a;
(4) reducing the mass of water in the beaker; Asbestos net;
(5)①7; Wrong reading; (2) continue to absorb heat, but the temperature remains unchanged; ③98; Less than.