The reason why you think his experiment can be successful is to measure the oxygen content in the air with the device shown in to be.

(1) Device B cannot be used to measure the oxygen content in the air, because the burning of charcoal will produce carbon dioxide gas, which will prevent water from entering the gas container.

Therefore, burning charcoal will produce carbon dioxide gas.

(2) Do you think the advantages of device A are energy saving and simple operation?

Therefore, it saves energy and is easy to operate.

(3) At the beginning of the experiment, due to high temperature and high air pressure, the piston moved to the right. After sufficient cooling, the piston should stay at scale 4 because about one-fifth of the oxygen in the device is consumed;

If the cooling is insufficient, the scale of the piston may be between 4 and 5. The judgment basis is as follows: if the cooling is insufficient, the temperature is higher than room temperature, and the gas pressure in the device is relatively high, the piston cannot stop at scale 4, and it should be between 4 and 5.

Therefore, fill in: Yes; 4; 4 and 5; The higher the temperature, the greater the gas pressure.