Today in chemistry class, we worked with dry ice. Before we started our lab, we talked about the different phases of matter and what the terms for each were. I learned that molecules in a solid are fixed in a position and can vibrate, Liquids have tight molecules but can slide around easily, and gasses have molecules that move around excessively. The goal of this lab was to observe the phases of matter using dry ice.
When we first started, we got to see dry ice by itself, as a solid. We moved it around on our tables and made many observations on it. The dry ice as a solid slid around the table, stayed in it's form, and you could hold it (for a very short time). We realized that the dry ice in solid form had a lot of the characteristics of solids that we found yesterday in our oobleck lab. The next step we took was watching the dry ice change from a solid to a liquid (melting). The dry ice was put in a tube, and became pressurized and the temperature increased until it was turned into a liquid. There was so much pressure in the tube that it made a small explosion when we popped off the cap. After seeing the dry ice in a liquid form, we wanted to watch it sublimate. In order to get the dry ice to turn from a solid to a gas, we had to "melt" the ice by putting it in water. As soon as we did this, a fog like mist started flowing out of the beaker. This was the gas that had been created by sublimation. For further experimentation, we put bubble juice around the rim of the beaker and watched as it formed large foggy bubbles. We could pop the bubbles and it would release the gas. Another thing we did for our lab with dry ice was putting a 2cm piece of it in a balloon and tied it off. The balloon slowly expanded because the gas (carbon dioxide) that was released from the dry ice slowly filled the balloon. Eventually the piece of dry ice inside the balloon melted, and the balloon stayed inflated because there was still gas trapped inside. After the balloon was fully inflated, we measured the diameter of the balloon. The diameter of our balloon was 20cm and the diameter of our dry ice was 2cm. In the picture below I solved for the volume of the sphere/balloon, volume of the gas, and volume of the solid using an equation. The answer I got for the volume of the balloon was the same as the volume of the gas, because when the balloon expands, the gas fills the space in the balloon completely. The answer I got for the volume of the solid was showing the amount of space that our substance occupied, in this case it was a small piece of dry ice. After I finished calculating these volumes, I found the ratio of one unit of carbon dioxide to the amount of space between the molecules. The ratio I found showed that in one solid unit of carbon dioxide, the gas molecules have about 1,000 times as much space between them as they did when they were a solid. This lab taught me a lot about the different phases of matter and how much molecules move around.
0 Comments
Today in chemistry class, we compared liquids and solids and brainstormed what individual characteristics they have. To compare liquids and solids, we first looked at a penny and a small cup of water. After working in our groups to determine what qualities they each have, we started to create oobleck. Oobleck is a mixture of cornstarch and water in an approximate ratio of 1:1.75.
Once we mixed all of the cornstarch and water together we had to determine if oobleck was a solid or liquid. Our group first played with the oobleck and decided that is had almost a clay like consistency when you held it in your fist and when you let it go it was almost like cake batter. We played with the oobleck for a while and then did several tests on it to determine if it was a sold or a liquid. We dropped the oobleck on the table and it made a noise, which is one of the qualities that a solid possesses. We also noticed you can hold the oobleck in a shape, or keep it from "melting" by squeezing it tight enough. One thing we also noticed was that liquids are more sensitive to movement, and the oobleck was not. The oobleck also had more force than what a regular liquid typically does. Based on all of these findings, we were able to conclude that oobleck is a solid. It can hold its form, even if only for a few seconds, which liquids typically can't. It was able to make a noise if thrown on the table, which liquids can't usually. You could also squeeze the oobleck and feel it in your hands, which is something you can't do with a liquid. We also noticed that most of the time, the oobleck looked as if it was holding it's shape (even if only for a few seconds). This means that the molecules didn't really move. They vibrated but didn't separate. All of these reasons and more are why my group and I believe that oobleck is a solid. For our lab safety poster, my partner Audrey S. and I decided to choose the wash your hands before leaving a lab rule. We chose this because we think washing your hands is a simple task, yet very important. To design our lab safety poster, we first thought of a pun to get peoples attention. Then after deciding on our slogan, we doodled and brainstormed until we eventually came up with this design.
"Advancing the frontier has advanced the culture." - Neil Degrasse Tyson
Why did you choose this quote? When I chose this quote, I thought about how something so simple could be so powerful. Science has improved our lives in so many ways. Scientific discoveries have provided us with amazing technology that allows us to connect with people all over the world. We are able to gain more access to what other cultures are like, and gain a deeper understanding of the life around us. This quote has also reminded me of how far we have come in life- and how much of it we owe to science and the discoveries and adventures people took. What does this quote mean to you? To me, this quote showed me not to be afraid. Instead of worrying what I might find and how I may feel about it, I should embrace science, for it is what allows us to discover so many wonderful things in life. I shouldn't so be skeptical about doing experiments and worrying if I'll do them right. Instead I should focus on what good can come out of it. Even if I fail, or the results aren't exactly what I wanted, I still was able to learn something. Being afraid to try new things and not exploring the world around us would be a major disadvantage to society. What thoughts does it provoke? After hearing this quote, I thought about how without science, our culture wouldn't be the same. We learn so much in life from new discoveries. Whether these discoveries are through talking to people around the world, traveling, or just looking at rocks in our backyards, we contribute something to society. We gain knowledge that can allow us the protect our planet, help others, and invent products that benefit the world around us. |
AuthorWrite something about yourself. No need to be fancy, just an overview. CategoriesArchives |