Week Seven

This week, we started by looking at the ethanol and colored water a little more. Now, though, we were focused on the concept of expansion, which is the process by which the volume of a substance increases, but mass stays the same. Also, expansion can occur without a state change, but it does require energy, as does a substance when its state changes. The change in height is a way to measure the expansion, but you can also measure the motion of particles by using the temperature. It measure the energy and the motion of particles. Then, we began our work with pressure. Pressure is measured in Pascals, and can be measure by taking force divided by area. Pressure is a push or a pull that is applied over a certain area. The more area there is, the less force that is applied at each point of pressure. We discovered this by doing an experiment in which a balloon was pressed onto a bed of needles, and it didn't pop. Then, the balloon was pressed onto a single needle, and it popped immediately. With this talk of pressure, we learned how we are able to drink through straws. We drink through straws by exerting a pulling force on the air in the straw. This makes it leave the system, which leaves no force pushing down on the liquid. Without this force pushing down, the liquid is able to rush up through the straw, therefore, you drinking it. To end the week, we were divided into several groups to do experiments each dealing with pressure. My group did one that compared pressure and temperature. We had a test tube that was closed and connected to a pressure meter. We placed the test tube in a beaker full of water, and instead of adding heat to the system, we used ice cubes to make the water colder. At five 40 second intervals, we added two ice cubes to the water and recorded the reading on the pressure meter. Our results showed that as temperature decreased, pressure did as well. This means that if temperature were to increase, then the pressure would increase with it. The past week in Chemistry was just again showing that learning is easy, and making it fun helps more than simply doing traditional homework.