In our project, we performed two experiments to prove the Combined Gas Law.
In our first experiment, we placed a temperature and a pressure sensor into an airtight flask, which were attached to a computer. We then filled one tub with hot water and another with cold water. Next, we dunked the flask in each container for 15 seconds. The attached censors recorded the temperature and pressure inside of the flask. All of the data was recorded on a graph in the computer. Our data showed that as temperature increased, pressure also increased; and as temperature decreased, pressure also decreased.
On the graph, the red line represents the amount of pressure in the flask and
the green line on the bottom shows the temperature in the flask.
The temperature of the water immediately affected the pressure of inside the
flask. When we switched the flask from cold water to warm water, we could see
a rise in the graph instantly. Unlike the pressure, the temperature took approximately
2 or 3 seconds for it to adjust.
The pressure in the flask at the lowest temperature
reached was about –5.39
kPa, at 282.3 Degrees Kelvin. The pressure in the flask at the highest
temperature reached was 6.11 kPa, at 309.3 degrees Kelvin. This project proved
Gas Law. Using the law,(P1 V1)/T1=(P2 V2)/T2, -5.39 kPa/282.3 degrees=6.11
kPa/309.3 degrees, which means that –0.02=. 01. Using the rounding
that we did, this is correct.
In our second experiment, we hooked up a 2-liter soda bottle to a bike pump by attaching a specially made “pump valve” for the soda bottle, which allowed us to pump air into the soda bottle. We put a thermometer into the bottle then pumped air into it, stopping at each 20 PSI. We recorded our information into a table, and made that into a graph.
We saw that temperature increased constantly by 2 degrees for every 20 PSI pumped into the bottle, starting at 22 degrees Celsius. This experiment also proved the Combined Gas Law. Using the formula, 40 PSI/297 Degrees=60 PSI/299 Degrees, which means that .0134=.2. Like the first experiment, with the rounding we did, this is correct.
In our first experiment, we used the Average Deviation formula to calculate error. We found that the percent of our error in this experiment was 0.3% because our experiment involved two constantly changing variables, we took the maximum and minimum pressure of each trial and compared them, they were very close to each other, which shows that there was not much mathematical error. As far as practical error, we saw none.
In our second experiment, we used the numbers found in the Combined Gas Law to
calculate the error. The average deviation in this experiment was .9%, which
is very good. As for as practical error, we saw none.
We felt that this experiment was a big success. With a minimum amount of error, our results were very accurate. Our experiment allowed us to full comprehend The Combined Gas Law. We accomplished al of our goals of proving the Combined Gas Law and having fun.