Can you identify and explain three possible sources of error in this lab for the experimental determination of absolute zero, by measuring the pressures of a fixed amount of gas at different temperatures and extrapolating the value of absolute zero? The procedure for the lab is the following:

- make a series of water baths at various temperatures

- submerge the gay-lussac's barometer in the liquid for a few minutes, to allow the gas in the device to reach the same temperature as the water

- take the temperature of the water, and the pressure on the gauge.

- repeat with liquid nitrogen