An intragastric device for weight management, the intragastric device comprising: a capsule having a longitudinal axis, the capsule configured to be readily swallowed by a human person; an inflation magnet provided within the capsule such that one of a north pole and a south pole of the inflation magnet is facing a first end of the capsule, the inflation magnet being displaced from the first end of the capsule, the inflation magnet configured to slideably engage the capsule during movement of the inflation magnet along the longitudinal axis, the inflation magnet configured to move towards the first end of the capsule during activation of the intragastric device by application of an inflation magnetic field externally to a user after the intragastric device has been swallowed by the user; a first chamber configured to store a first chemical therein; a second chamber configured to store a second chemical therein; a partition configured to physically separate the first chamber from the second chamber, the partition having a through hole, the inflation magnet provided between the partition and the first end of the capsule, the first chamber defined within the capsule at least partially between the inflation magnet and the partition, the second chamber defined at least partially by the partition and the capsule; a separator sealing the through hole in the partition before activation of the intragastric device, the separator being connected to the inflation magnet wherein movement of the inflation magnet towards the first end of the capsule moves the separator to unseal the through hole; wherein fluid communication is established between the first chamber and the second chamber via the through hole when the through hole is unsealed to allow a chemical reaction between the first chemical and the second chemical; a balloon secured to the capsule and collapsed against an outer surface of the capsule before activation of the intragastric device; and an expandable volume defined at least partially by the balloon and the outer surface of the capsule, the expandable volume configured to expand when the balloon is inflated by a gaseous product of the chemical reaction. a capsule having a longitudinal axis, the capsule configured to be readily swallowed by a human person; an inflation magnet provided within the capsule such that one of a north pole and a south pole of the inflation magnet is facing a first end of the capsule, the inflation magnet being displaced from the first end of the capsule, the inflation magnet configured to slideably engage the capsule during movement of the inflation magnet along the longitudinal axis, the inflation magnet configured to move towards the first end of the capsule during activation of the intragastric device by application of an inflation magnetic field externally to a user after the intragastric device has been swallowed by the user; a first chamber configured to store a first chemical therein; a second chamber configured to store a second chemical therein; a partition configured to physically separate the first chamber from the second chamber, the partition having a through hole, the inflation magnet provided between the partition and the first end of the capsule, the first chamber defined within the capsule at least partially between the inflation magnet and the partition, the second chamber defined at least partially by the partition and the capsule; a separator sealing the through hole in the partition before activation of the intragastric device, the separator being connected to the inflation magnet wherein movement of the inflation magnet towards the first end of the capsule moves the separator to unseal the through hole; wherein fluid communication is established between the first chamber and the second chamber via the through hole when the through hole is unsealed to allow a chemical reaction between the first chemical and the second chemical; a balloon secured to the capsule and collapsed against an outer surface of the capsule before activation of the intragastric device; and an expandable volume defined at least partially by the balloon and the outer surface of the capsule, the expandable volume configured to expand when the balloon is inflated by a gaseous product of the chemical reaction.