Pressure

      The main ideas we learned this week are pressure, and how volume, the number of particles, and temperature affects pressure. These main ideas connect because over this past week we were using volume, number of particles, and temperature to see how they affected pressure. Some important details were learning how to use a gas pressure sensor and learning how to use a data analyzing and graphing software called Logger Pro. We did three experiments this past week all involving pressure. The first one was Pressure vs. Volume, then Pressure vs. Number of Particles, and lastly Pressure vs. Temperature.

Graphs of Pressure vs. Volume, Number of Particles, and Temperature 

Experiment 1- Pressure vs. Volume
The first thing that we did was attach the gas pressure sensor to the Logger Pro interface. Then we changed the Logger Pro settings to fit the experiment. Then we put the syringe that was attached to the gas pressure sensor at 10mL. Then we clicked the green run button, and the wheel button that marked the point on the graph. We then repeated this process four more times making sure to only move the syringe by 2mL between each reading. When taking the reading it was important that we held the plunger very steady in order to get a accurate reading. For this process my group had two people taking the reading. One person was holding it still and the other was working the computer. We learned that Volume negatively affects pressure.

Gas pressure sensor and syringe

Experiment 2- Pressure vs. Number of Particles
The first thing that we did was attach the gas pressure sensor to the Logger Pro interface and set up the Logger Pro graph options just like in the Pressure vs. Volume experiment. To start we put the syringe at 5mL and hit the run button and the wheel to record the data. We the moved the syringe to 7mL and pushed it back down to 5mL and recorded it. We the repeated the steps three more times only moving the syringe up by two each time and then pushing it back down to five. It is important that you take out the syringe when changing the volume and then put it back in before you push it down to 5mL. You can also do lower volumes and bring them back up to five. We learned that number of particles positively affects pressure.

Experiment 3- Pressure vs. Temperature
The first thing we did after setting up the experiments like the past ones was to put a stopper in a flask, then put the flask in a 600mL beaker. Then we put a temperature probe in the beaker. Then we clicked the wheel button and this gave us the temperature reading of room temperature. Then we added hot water into the beaker to get a reading. To get an accurate reading in a liquid you have to make sure you swirl the flask in the liquid. You also have to wait to graph the reading until the temperature becomes stable in order to get an accurate reading. To get a warm reading pour out half of the hot water and then add slightly cool water to the hot water. To get the cold reading pour out all the water in the cup and add all cool water. Then we added a couple cubes of ice to get a temperature reading. To get the very cold reading you pour out all of the water and submerge the beaker in a tub of a frozen mixture of alcohol and water. This mixture's reading should be colder than the ice reading. We learned that temperature positively affects pressure.

Lab setup for Experiment 3

Reflection-
We came to know and understand the ideas we learned last week through experiments. I still have questions about why temperature affects pressure. I think my participation in class this past week was really good this week. I need to work on allowing other people to do the work and encouraging them to do be able to do the work without me. I would rate myself a 9 out of ten because I understand almost all of the concepts. I still need to work on reflecting more in my notebook about the experiments we do. My ideas have changed because now I know some of the variables that affect pressure.