Palm Pipe Lab

Palm Pipe Lab:
      For our most recent lab in class, we were assigned to find out what musical note a certain piece of PVC pipe would play if we smacked one end of the pipe against our palms. We began by finding the length of the pipe and the diameter of the hole. We would then plug these values into an equation that would help us find the wavelength of that particular pipe. (Length = Wavelength/4  -  Diameter/4)
After plugging in our values into this equation and solving, we would get a wavelength value, and plug that into another equation. (Speed = Frequency x Wavelength) This equation allowed us to find the frequency and from there we entered our frequency value into a Wolfram Alpha app which told us the musical note of the frequency we found. 
      Once our whole class found their musical notes, we played a couple songs like Happy Birthday and Twinkle Twinkle Little Star by smacking our pipes in our hands in the correct order. This lab was really just good practice for using our equations and learning more about wavelengths. It also helped me understand more about the different harmonics in pipes and how they're different from the harmonics in strings.

(Using the Palm Pipe)

(Labquest, showing the FFT graph of the palm pipe)

Light & Optics Real World Conncetion

Physics Explanation:

      In this picture, I just used a laser pointer and pointed it towards a mirror at an angle. (By turning off the light and spraying water in the air we can see the actual beams.) This mirror is simply a straight mirror so the beam of light coming from the right side of the picture hits the mirror and bounces off to the left as we can see in the picture.

    This relates to what we've been doing in class regarding our law of reflection, Oi = Or. From my point of view, there is a tangent line flat across the mirror and a normal line (perpendicular) coming straight out towards us. The 1st light beam (angle of incidence) on the right hits the mirror at an angle going left and immediately bounces off at the same angle (angle of reflection). These two light beams are split by the normal line between them. Basically, the distance from each beam to the normal line is the same.

Magnetism

Standard 6.3: Explain how objects like the earth and metals can be permanent or temporary magnets.

      The earth itself has a very large magnetic field which is caused by the molten iron/nickel core that is always moving. Although the earth has many permanent magnets, the planet itself is not one. The most common example of a permanent magnet would be a regular fridge magnet. These magnets are permanent (always magnetic) because they have tiny magnetic domains that line up and point in the same direction. Most objects have these domains, but they are all scattered and point in different directions, making them non-magnetic objects.

      A temporary magnet on the other hand is basically a magnet that can be turned on and off. It requires a flow of electrical current to create a magnetic force for the metal to exert. Electromagnets are the best examples because all they're really made of is metal and coiled wire. When an electrical current flows through those wires the metal becomes magnetic, thus allowing the magnet to be turned on or off with the flip of a switch.

(Nail Electromagnet)

      

Lemon Battery Lab (Real World Connection)

Link:

http://www.griffintechnology.com/blog/tutorial/what-you-need-to-know-about-lithium-batteries/

Inside of all of our iPads is an Lithium ion battery. Made out of polymer, this battery is unique because unlike most other batteries, it can be recharged. Apple says that for the first two hours of charging, your iPad battery will charge up to 80%. For the next two hours it will "trickle charge" slowly to complete the charge at 100%. With each new iPad release, the battery life has always stayed the same (10 hours), so we're led to believe that they won't be focusing on increasing the battery life time, but focusing more on expanding the capabilities of the ipad during those 10 hours. 

Real World Connection:

These iPads are really very complicated innovations, and thankfully, learning many of these new concepts in class helped me to better understand how they work. In the past few class days we learned about voltage and electricity and how they relate to each other. One analogy we used to help us learn was that voltage was similar to a gravitational field, surrounding an object. But I think the most helpful piece of information was learning how regular batteries work. The electrons from the (-) side flow through the electronic device into the (+) side, and eventually the (-) electrons will run out and the battery will die. I really felt like this concept was the most helpful while learning about all different types of batteries, like the ones in our iPads. 

Projectile Motion Reflection on Learning

     In our most recent lab, we performed an experiment which helped us to better understand what a projectile is and which forces are acting on it. We began by taking a basketball and shooting it into the air at an angle. By taking a video of this, we were able to create some graphs and visual images that would help us understand the ball's pattern in the air. 

      These screenshots show graphs that each give different information about the projectile (basketball). The two bottom graphs in particular show the velocity of the ball in relation to the amount of time it was in the air (Vx and Vy).  The bottom right graph shows us a line which crosses the X-axis at some point. Looking on the graph, we see that it crosses the axis at around 2.5 seconds. This is the exact time at which the ball is at its peak. It has stopped going up and has not yet started falling down. 

      I think the most important concept I learned from this lab was that all projectiles only have one force acting on them. In this case the force was gravity. All of our work is shown below on our whiteboard:

Forces in 2D & Circular Motion (Big Questions)

Questions:
1. What does it mean to analyze forces in 2D?
2. How do forces cause objects to move in a circle?
3. What does it mean to be in orbit? How do satellites orbit planets? How do the planets orbit the sun?

Response:
      In the past week of physics class, we've started studying forces in 2D. For example, if we were to see a tension force of say 60N acting on an object, we would also be asked to calculate the Fy and the Fx values. This type of work really goes back to geometry where we used SOH CAH TOA to help us find our x and y values. Overall, finding these values can help us to calculate the net force acting on the object and help us to better understand the problem.
      We also performed a few labs during the week that helped us to understand these forces. In our hover disk lab, we learned more about how tension can keep an object moving in a circle. We had a string connected to our hover disks and simply spun the disks around us in a circle. The disk continued to move in a circle around me because I was holding the string (tension force) that kept it going in circles. (Although the hover disk was moving at a constant speed, it was technically accelerating because it was constantly changing directions.) However, if I were to release that string, the disk would fly off in a straight line (90 degrees from the tension string) and continue getting farther and farther away from me.
      This concept of tension keeping an object going in circles also helped me to understand how things can stay in orbit. Instead of a tension force, simply think of a gravitational force. When something is in orbit, it is constantly moving around another object. Think of satellites. The satellites that stay in orbit are technically falling towards the earth at all times. They just go so fast while "falling" that they miss the earth and continue going right back around again. This same idea also applies to the planets orbiting the sun.