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krdavis18

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Blog Entries posted by krdavis18

  1. krdavis18
    When you pull up to the intersection to turn onto my street, the traffic light is able to detect that my car has pulled up. Have you ever wondered how this is possible? I thought I'd explore more into this capability. The most common method is the use of an inductive loop which is a simple coil of wire within the surface of the road. https://auto.howstuffworks.com/car-driving-safety/safety-regulatory-devices/question234.htm This website gives a great example of how this process works.

    With this image as a reference, they write the following: "So... Let's say you take a coil of wire perhaps 5 feet in diameter, containing five or six loops of wire. You cut some grooves in a road and place the coil in the grooves. You attach an inductance meter to the coil and see what the inductance of the coil is. Now you park a car over the coil and check the inductance again. The inductance will be much larger because of the large steel object positioned in the loop's magnetic field. The car parked over the coil is acting like the core of the inductor, and its presence changes the inductance of the coil."
    For more information you can click on the link above. It's pretty cool to finally understand this process! 
  2. krdavis18

    Solar Street Lights

    By krdavis18,

    Solar street lights are becoming increasingly popular as a green alternative because they are a better value for their cost, have lower maintenance, and easier installation. But have you ever wondered how these technological advancements function? What powers it and how does it turn on at night? I decided to look into this and examine the circuits behind the lighting of a street lamp. 
                                                                                                           
    If you look at this picture, you can see the solar panel on top of the light that charges a battery inside the circuit during the day when the sun is shining on the lamp. Then when the sun goes down, the solar panel acts as a photocell and turns the light fixture on.  Photocells work by turning light into a form of energy.  A better way to describe them is that they are basically a resistor that changes its resistance depending on how much light is being shown on it. As light level increases, resistance goes down and allows the current to increase in a circuit. In reality, you can dive much further into how photocells and CdS cells work, but this basic understanding is simple enough for me for now. Below I have included a picture of a simple photocell. I have also included a picture that describes how a typical circuit in a street light might work to store the energy it converts from sunlight to provide light when the sun goes down at night. For more information on how this circuit works you can visit this website: https://science.howstuffworks.com/environmental/energy/question363.htm This is a very cool concept that I hope to learn more about in the future because I would like to become an electrical or possibly environmental engineer. 
                                                                            
     
  3. krdavis18

    Galileo Thermometer

    By krdavis18,

    Have you ever seen a Galileo Thermometer? They are a pretty cool way of telling what the temperature is and it also serves as a cool decoration for your home. The thermometer has little glass bubbles with different color liquid inside of them. Each little bubble has a tag on them with a different reading of the temperature. You read a Galileo thermometer by reading the tag on the lowest bubble that is still floating. The way the thermometer works to change to different temperatures involves a bit of physics. 
                                                                                                                     
    An object immersed in fluid experiences two forces, the downward force of gravity and the upward force of buoyancy. In the Galileo thermometer, its the downward force of gravity that makes it work. Each of the tags on the different bubbles has a different calibrated weight, making each one a slightly different weight from the others. The liquid inside the each of the bubbles has the same density, so that when the weighted tags are added, each bubble has a slightly different density then the others due to the ratio of mass to volume. The density of all of the bubbles is very close to the density of the surrounding water. Therefore, as the temperature outside the thermometer changes, the temperature of the water the bubbles are immersed in also changes. When the temperature of the water changes, it either expands or contracts which changes its density. So at any given density, some of the bubbles will float and others will sink. So for example, if the temperature is increasing, the waters density decreases. So the bubble with a tag that says 72 degrees, for example, will have now have a weight per unit volume that is greater than that of the surrounding water rather than lighter, and it will sink to the bottom. Very neat! 
  4. krdavis18
    While doing some exploring on the internet, I stumbled across this video that does a pretty decent job of explaining a crazy pool vortex that forms when you push a plate through pool water. The woman in the video lists some examples of vortexes which include water going down a drain, hurricanes, tornadoes, and air going over a plane. In the example with the plate, the difference in velocity between the water moving with the plate and the stationary water next to it causes a shear force and makes the water spin. The vortexes keep spinning because of angular momentum and minor friction. She also examines what happens when a vortex line is curved or a complete circle like in a smoke ring, bubble ring, or even the plume rising up from an explosion. This seemed interesting to me so I decided to explore more behind what creates a plume after an explosion. 
    The plume formed after an explosion, often called a mushroom cloud, is best known for occurring after nuclear explosions. Below is a picture from WWII of the atomic bomb explosion over Nagasaki, Japan. Some simple physics can explain the phenomenon behind the forming of this cloud. When the explosion occurs, the hot burning gases which are less dense than the surrounding air, rises up fast, creating a vacuum affect that pulls cool air up into the cloud. This is called the Raleigh-Taylor instability which occurs when two different substances of different densities interact. I've included an additional video that better explains this stunning affect. Enjoy!
                                                                             
     
     
  5. krdavis18
    This year, I really pushed myself with new challenges that were difficult, but also very rewarding. I took on the challenge of a flipped classroom and learned a new way to be a student that will help prepare me for college. While at times it was a struggle to keep up, this course kept helped me prepare for college by forcing me to work on my time management skills. I think that I have a lot more of improvement to do on this, but I have come a long way from the beginning of the year. I think before I go to college, it might be a good idea to review Dr. Chew's videos and brush up on some of the proper learning techniques that he taught. Another new thing that I took on this year was completing blog posts for this class. This activity taught me a lot of new things about how what we are learning in physics applies to the real world and I really appreciate all that I have learned. Going forward, I will have to apply the math and physics of the classroom to the real world, and doing the blog posts gave me a little bit of insight into the connections between the two. Although it may have been a challenge at times to complete the necessary blog post on time, I enjoyed learning new things about the world around me. 

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