About BMP180 :
I am trying to use this sensor for experiment of Boyle-Charles at middle school class. I inserted this sensor in glass bottle and sealed it very tightly using rubber stopper. 4 stainless steel pins obtained from cutting clips were inserted through the rubber and soldered each pins to BMP180 connection lines. After I put the glass bottle into water, I increased the water temperature and read temperature and pressure change at every 10 min. I heated water for 1 min and wait until temperature and pressure reading constant, and recorded. I waited since the temperature equilibrium of air in bottle is taking time.
What I expected from this experiment, ratio of pressure and temperature will be constant or at least close to constant, but the ratio decreased with temperature. I checked any leaked in the sealing of bottle, but there was no leak at all.
I wonder the pressure reading of BMP180 is effected with temperature change. I know that the pressure reading is corrected by temperature reading according to BMP180 Arduino library. But the correction would not good enough for my work in Boyle-Charles experiment.
How did you check for leaks? I hope you realise that it's REALLY hard to make something truly airtight, especially if you exert pressure.
Glass bottles and pressure sounds like a very dangerous thing, too, unless it's a special high pressure one. Exploding glass can do pretty ugly things to people that happen to be nearby.
Besides, you obviously ignored the sticky on top of the forum, or you would have known to start your own thread instead of hijacking one.
Show your data. How far are you off?