Does water boil at the same temperature every where?
No: at higher altitudes (= lower pressures) water boils at lower temperatures and vice-versa. On Mars the air pressure at ground level is so low (equivalent of about 100,000ft high on Earth) that water would go straight from ice to steam (sublimation). Pressure cooking uses the opposite principle: water boils at higher temperatures as pressure is increased, so instead of steaming/boiling food at 100 Celsius you’re typically doing so at around 115 Celsius. I can’t remember the altitude, but on one Himalayan mountaineering trip I went on the water boiled at around 78 Celsius which made useless tea and manky coffee!
