To explain why only a 2 hPa peak (or peaks) are obtained out of about 35 hPa pressure in the balloon is really a question.
First of all I have verified pressure in the balloon blowing up. The technique using the SensorTag and a small jar which is cited above was applied. It gave also the maximum pressure of about 50 hPa (the pressure were reducing with the balloon growing, see figure).
Then the experiment of Eric was repeated with the black balloon. The material used is on the photo below. The needle was initially inserted in the wine bottle cork to pop the balloon inside the bag (and not trough it in order to preserve its hermeticity ).
The pop sound is so strong that the measurements by the SensorTag were stopped. The phone measured some peaks of about 2 hPa as is presented by Eric.
First of all I have verified pressure in the balloon blowing up. The technique using the SensorTag and a small jar which is cited above was applied. It gave also the maximum pressure of about 50 hPa (the pressure were reducing with the balloon growing, see figure).
Then the experiment of Eric was repeated with the black balloon. The material used is on the photo below. The needle was initially inserted in the wine bottle cork to pop the balloon inside the bag (and not trough it in order to preserve its hermeticity ).
The pop sound is so strong that the measurements by the SensorTag were stopped. The phone measured some peaks of about 2 hPa as is presented by Eric.
No explanation for the moment...