Steam condenses in the tube, this flows down into the flask Pressure in the flask is decreased Boiling temperature is decreased Amount if boiling is increased The steam is at a higher temperature than the tube which causes the steam to condense and flow down into the flask Because water has a lower density than steam the pressure in the flask is decreased and the boiling temperature decreases Therefore the amount of boiling increases. The increased boiling rate causes the pressure in the flask to increase which also increases the Pressure is increased Boiling slows rapidly

Decreasing pressure below atmospheric Water is pushed down the tube from the catch basin Temperature in the flask is decreased Period of quiet while system regains heat energy Eruption begins again Because the pressure acting on the water in the catch basin than the pressure inside the flask, the water from the catch basin is forced down the tube into the flask This water is at a lower temperature as it was losing heat energy while in the catch basin because of this the temperature of the water in the flask is decreased The loss of heat energy means the system cannot continue erupting and a period of quite follows while the system regains the lost heat energy When the temperature is high enough, the cycle starts again Steam generates and so on

“Time Dependence” What we Measured Time Between Eruptions Length of Eruptions How it Could Change Longer or Shorter More or Less Variable The question asked us to investigate the time dependence of the eruption process. We chose to separate Time Between Eruptions and Eruption Length because I thought one of the variables I test might affect one of these times but not the other and this was an affect I thought might be significant.

1. Tube Length Length of Tube in Flask Control Variables Tube diameter Internal 4mm Total 6mm Height Above Heat 120mm Water in Catch Basin To Ring Length of Tube in Flask 25mm Explain what changed in each test and that the length of tube in flask was kept the same (2.5mm)

This graph shows a shallow downwards trend – this means the length of eruptions gets shorter as tube length gets For the longer tube there is more water in the catch basin therefore there is greater hydrostatic pressure which means the pressure in the flask doesn’t have to drop as much before the water in the catch basin is pushed down the tube. It also shows a large decrease in variation of eruption length as the tube length increases. Because of the shape of the catch basin (funnel) a small difference in the water volume with a short tube has a greater effect on the surface area of the water in the catch basin.

I expected the longer tube lengths would result in a longer time between eruptions however this graph showed no clear pattern I have no explanation for this currently and so would have to collect more data to give a conclusive answer

2. Length of Tube in Flask Control Variables Tube diameter Internal 4mm Total 6mm Height Above Heat 120mm Water in Catch Basin To Ring Tube Length 524mm Explain what I changed in each test and that the length of tube was kept the same (524mm)

This graph shows a clear upwards trend This graph shows a clear upwards trend. Time between eruptions increased as the length of tube in the flask increased Explanation/Interpretation More water in the system so more water at top More surface area at top so more heat energy lost More water to be reheated to boiling temperature before next eruptions The length with the most variation is 2.5 which was the length used in tube length test. Could have contributed to the high level of variation in previous graphs. Data points are relatively close together with few outliers

Just like in the previous graph there is an upwards trend Just like in the previous graph there is an upwards trend. When the length of tube in the flask is increased the eruption length increases also Explanation/Interpretation More water is moved around the system

Conclusions Tube Length Tube length may have an affect on time between eruptions but more data is needed before this could be determined Eruption length gets shorter as tube length gets longer Length of Tube in Flask Time between eruptions increased as the length of tube in the flask increased The eruption length increases when the length of tube in the flask is increased

References Geyser Model with Real Time Data Collection – By Samo Lasic & Gorazd Planinsic from the University of Ljubljana, Slovenia

Thanks to… Britney Kerr Jamie Simonsen Mac Karalus David Sturrock Drew McGlashen Melanie Hunter