Wearable apparatus for measurements of a user's physiological context

A wearable device, comprising:

• a chamber to be disposed in proximity to or in contact with a body of a user, wherein the chamber includes a first opening to allow evaporation from the body to enter the chamber, and a second opening to allow the evaporation to exit the chamber;
• first and second sensors disposed inside the chamber at different distances from the first opening, to detect the evaporation from the body;
• and
• circuitry coupled with the first and second sensors to receive evaporation readings from the first and second sensors, and to determine an evaporation parameter based at least in part on the readings.

A method, comprising:

• providing a chamber with a first side and a second side opposite the first side, including forming a first opening in the first side, to allow evaporation from a surface in proximity or in contact with the first side to enter the chamber, and forming a second opening in the chamber to allow the evaporation to exit the chamber;
• disposing first and second sensors inside the chamber, to detect the evaporation from the surface;
• disposing a processing block inside the chamber;
• and
• providing a communication path between the first and second sensors and the processing block, to measure the evaporation based at least in part on evaporation readings provided by the first and second sensors to the processing block via the communication path.