This week I read an article about the polar vortex. In class, we’ve been conducting a number of labs concerning snow, rain, and the temperature, pressure, and density of air and water. The article relates to what we’re learning because the polar vortex is made possible by these factors, and to fully understand the vortex, you should understand the factors that allow for its existence as well. This article made me think about how the weather is in many ways just different reactions caused by interactions between a number of ‘building blocks’ that always stay the same, or maybe ingredients that can be mixed together in different ways to create different weather events.
Having A Meltdown
Snow and rain are both water, but are the same and different in many more ways than that. This week in class we conducted a lab called “Having A Meltdown,” in which we took the mass of 10, 15, and 20ml of water and snow and divided that by the volume to get the densities. I hypothesized that the water and snow would have the same volume, because there would be 200mL of each, but that the mass of each would be different - that the mass of the water would be greater, because it would be denser. After we calculated and averaged our findings, we concluded that the average density of water was 0.906 and the average density of snow was 0.733. Later, we learned that our results were off by a small margin, due to human error during the experiment. Using the correct values, we created a graph to represent that densities of snow, water, and ice -- around 0.5 for snow (because of the different types of snow, densities vary), 1.0 for water, and 0.92 for ice. You can then use the equation m = DV, a proportionality constant of the equation D = m/v, to use the density of different materials to calculate their mass or volume. For instance, if you wanted to calculate the mass of 200mLs of water vs. ice, you could create the equations m = 1(200) for water and m = 0.92(200) to compare the two. To contrast -- both snow and water are made up of H₂O, and are the same substance (water) undergoing phase changes. Their differences include their density, which affects the mass to volume ratio of each.The Polar Vortex
An air mass is a body of air characterized by its uniform temperature, humidity, and pressure. The temperature just has to be uniform within the mass, not with the surrounding air, so you can have warm air masses and cold air masses. Warm air is less dense than cold air because, when warm, the air molecules spread farther apart, spreading the mass out and creating more volume. This means that warm air will rise above the denser cold air. In the article we read, it said that “The polar vortex is created because cold air takes up less space than warm air. Cold air above the arctic sinks, and new air rushes in to take its place.”’ In other words, when warm and cold air masses meet, the dance of rising and falling that occur can create a polar vortex. The article also explains that, odd though it may sound, the best polar vortex is a “strong and healthy” polar vortex. This is because a polar vortex is far less likely to ‘break apart’ and cause polar vortex events if it has a healthy flow, staying in line instead of sending random pieces of cold air down the jet stream.Front and Center
Another experiment we performed in class was called Front and Center. In this experiment, we poured two 200mL cylinders of water into a divided container. One of the 200mLs was cold tap water and the other was hot enough that we could burn ourselves on the glass. In each cylinder, we added a drop of food coloring -- blue for the cold water, green for the warm -- to differentiate them. Once we had poured the two cylinders in their compartment, we removed the divider, causing an interesting and beautiful reaction. Before we performed the experiment, I had hypothesized that because the two temperatures would create two different densities, the water would separate, the cold water at the bottom and hot water on top. This hypothesis was correct - when the two masses of water touched, they mixed slightly at the edges, then do-si-doed, with the hot green water rising to the top and the blue water sinking to the bottom. Where they touched they transferred heat, creating a turquoise zone as well. This reaction occurred for the same reason I hypothesized it would -- when the water is warmer, the molecules push farther apart, making it less dense and therefore likely to rise above the denser cold water. Despite my hypothesis’ accuracy, performing and seeing the result of the experiment for myself was a fascinating experience, because the reaction was so distinct. In conclusion, when mixed, denser fluids will sink and less dense fluids will rise.In conclusion, I learned a lot this week about density and phase changes, as well as about the polar vortex, thanks to the article we read. It will be very interesting to see how it all connects as part of the cosmic sandbox that creates weather.
