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Please ignore the questions:
- What gas laws apply to geysers and why? (Apparently Sahib and I are supposed to answer that, oops.)
- What can a geyser be compared to? Does it use the same concepts and gas laws as geysers? If yes, how so? (Answered this while answering the first question.)
- How is this pressure built up? (Also answered this while answering the first question.) Our understanding of how geysers work:
A geyser uses three things to work: a water supply (cool water to refill geyser), a heat source (hot water, forced up through cracks under high pressure), and a pressure tight plumbing system of vertical shafts to store water, as it is heated. An eruption cycle starts by filling the geyser with hot water from below. Cooler water also starts filling the geyser, mixing with the hot water from below, raising the water level over time. As the water rises the pressure at the bottom increases due to the weight of the liquid above. Boiling does not occur because of the cool water and its increased pressure. But as the hot water below heats the cool water, the water temperature increases, until all the water in the geyser is close to boiling point. Eventually bubbles rise and spill off some water from the top, causing pressure to decrease, allowing the water to boil and turn to steam. Larger bubbles will start to rise and the pressure of the steam will cause and eruption.
Also the force of eruption depends on the difference in pressure between the geyser and atmosphere. The greater the pressure of steam in the geyser, greater the eruption. This is similar to how a barometer works.
Geysers are similar to the experiment done in class, where we had to put water into a pop can, and heat it up, then flip it upside down, into cold water, causing it to pop.

Applying a Gas Law to Geysers:
Gay-Lussac's law applies to how geysers work. The law states: at constant volume, the pressure of a fixed mass of any gas is directly proportional to its Kelvin temperature. As the temperature of the water in the geyser increases close to boiling point for that depth, it causes pressure to increase. Eventually the pressure causes bubbles to rise up to the surface, and this will result in