There are two identical beakers, each containing the same volume of water and alcohol, but there is no label. Xiao Li used the smell method to judge that odorless water is small.

(1) If the air tightness of the pressure gauge is poor, there will be air leakage when the rubber film is lightly pressed or heavily pressed with your fingers, so the height difference of the liquid column on both sides of the U-shaped pipe has little change;

If the metal box of the pressure gauge is in the air, the liquid level on both sides of the U-shaped tube is not level. In this case, the adjustment method is to remove the hose and then reinstall it.

(2) The factors that affect the liquid pressure are: the density of the liquid and the depth of immersion in the liquid. In the experiment, the immersion depth of the metal box is not controlled at the same level, so it is impossible to draw a correct conclusion. The correct way is: he should immerse the metal box in the same depth of liquid;

(3) In the same liquid, the deeper the distance between the metal box and the liquid level, the greater the height difference of the liquid columns on both sides of the U-shaped tube, which means the greater the pressure of the liquid;

(4) At the same depth, the pressure of the liquid in all directions is equal, so when the distance between the metal box and the liquid level is the same, only the direction of the metal box is changed, and the height difference of the liquid column on both sides of the U-shaped tube remains unchanged;

(5) According to the influencing factors of liquid internal pressure, that is, p=ρgh is available and h=pρg, so if P is the same, G is the same, and if ρ becomes smaller, H becomes larger. Therefore, if the U-shaped tube in this question uses a liquid with low density, and if the height difference between the two liquid levels of the U-shaped tube is still 5cm, the metal box should be immersed in the measured liquid deeper.

Therefore, the answer is: (1) small; Remove the hose and reinstall it; (2) The immersion depth of the two metal boxes is different. (3) large; Big; (4) unchanged; Equality; (5) deep.