Palm Pipe Lab

In this lab, we determined the musical notes that our palm pipes produced. First, we measured the length and diameter of our palm pipes and converted our measurements from cm to m. Second, we solved for wavelength: L=1/4(wavelength) - 1/4(diameter). After finding wavelength we then solved for frequency: V=(wavelength)(frequency). After finding our "peak" frequency, we then plugged it in to Wolfram Alpha to help us determine our musical note.

Rainbows

The photo above is a photo I took of a rainbow outside of my house. I chose this picture because we are learning about light and refraction. A rainbow is formed when a light ray passes through a spherical water droplet and is reflected and refracted. This is like the car and the sand diagram. The light enters the water droplet at almost an angle and the different rays of color change speeds through the droplet. The light that enters is then reflected off the opposite side of the droplet and changes the direction of the light. When the light leaves the water droplet, the light ray is dispersed and the different color rays (ROYGBIV) are refracted down toward earth.

Magnetism

Magnetic fields can create electricity/ currents. When you move a wire though a magnetic field, it creates a current. This can be related to the hand generator we used in class. To create a current, you not only need a magnet and a coil of wire, but also movement. When you crank the handle, the magnet is moved in and out the wire, and this creates a current, because the electrons in the wire interact with the poles of the magnet. When current flows, the wire becomes magnetic. When the current is revered, the polarity of the magnet switches. In other words, the North and South orientation switches. The higher the electric current and the greater number of loops in the wire contribute to a stronger the magnetic field.

iPad & Lemon Battery

In an iPod, computer, iPad, and many more things there is a battery called an ion lithium battery. Each cell of a lithium- ion battery produces about 3.7 volts, while the average AA battery produces 1.5 volts. Lithium-ion batteries are popular because they have a number of important advantages over competing technologies.
1) They're generally much lighter than other types of rechargeable batteries of the same size. The electrodes of a lithium-ion battery are made of lightweight lithium and carbon. Lithium is also a highly reactive element, meaning that a lot of energy can be stored in its atomic bonds
2) They hold their charge. A lithium-ion battery pack loses only about 5 percent of its charge per month, compared to a 20 percent loss per month for NiMH batteries.
3)They have no memory effect, which means that you do not have to completely discharge them before recharging, as with some other battery chemistries.
4)Lithium-ion batteries can handle hundreds of charge/discharge cycles.
(http://electronics.howstuffworks.com/everyday-tech/lithium-ion-battery.htm)

In class we made our own battery by using a lemon, a penny, and a nail.  In class we discussed voltage, which is a field surrounded a charged object. The lemon acted as a battery, and the nail and the wires as charges. In class we used these to see how much voltage we could make and to see if we could make a little light go on. 

Projectile Motion

Big Questions: "What is a projectile?" and "What is the general path of motion? Why?" 

In this lab, we used the Vernier Video Physics app to analyze the projectile motion of a basketball shot into the air. One of my classmates took a video of me shooting a basketball and I used this app  to make a motion map on the video and then it produced X vs. Y charts. The X is the motion in the horizontal direction and the Y is the motion in the vertical direction. A projectile is an object propelled by an external force. The general path of motion of a projectile is a parabolic arc.

For the motion in the X direction:
-Velocity is constant
-Acceleration is always 0
-Never speeds up, slows down or stops
The two equations we derived were:
- Vx=Vxi
-Xf=Vxt+xi

For motion in the Y direction:
-Velocity is changing
-Acceleration is always -10m/s
The two equations we derived were:
-Vy=(-10m/s)t+Viy
-y=1/2(-10m/s)t^+Viyt+yi

Hover Disk- Centripetal Force

Big Questions: "How do forces cause objects to move in circles?" "What does it mean to be in orbit? How do satellites orbit planets and how do planets orbit the Sun?"

To answer these questions we used a hover disc attached to a string. We held the string and spun in a circle--imitating the gravitational pull of the moon orbiting the Earth. In order to analyze forces in two directions, two vectors need to be involved. Vectors need speed and direction. When objects move in a circle, their velocities want them to keep moving in a straight line. However normal forces from seats and doors cause the direction of our velocity to change and causes us to go in a circle. In this specific lab, there is a tension force between the person and the disk--the string. This tension force's direction is inward towards the person. When an object is shot into space, gravity pulls the object down at great speeds. The object is basically falling toward Earth, but misses because the Earth is also rotating. This is how satellites and space stations orbit Earth. The planets orbit the sun because of sun's gravitational force. Since there are no other forces in space, the planets only have the sun's gravitational field. The Earth has a velocity that is perpendicular to the Sun's gravitational pull. We then made an interaction between the person, the disk and the Earth. Between the person and the Earth, there is gravitational and normal force. Between the disk and the Earth there are normal, gravitational and friction forces.There is also a tension force between the person and the disk.

Fan Cart Lab

Purpose: The purpose of this lab was to answer the Big Question, "What is the relationship between mass, force and acceleration?"We answered this question throughout our let when we tested the acceleration of each fan cart mass.

How?: In this lab, we started by measuring the mass of fan cart (300 g). Then we recored the acceleration of the fan cart without any added mass, and recorded our data in the Time vs. Velocity graph by measuring the slope. We then repeated this many times, each time with a different mass. We started to notice that the slope of the line in our graph changed each time.

Graph: These two graphs represent the different accelerations of the fan cart. The first one, represents the fan cart's initial  acceleration without any added mass (300 g). The second graph is the fan cart's acceleration with the greatest amount of mass added (1300 g).

Conclusion: Based on our data, we concluded that there is an inverse relationship between acceleration and mass. As mass increases, acceleration decreases, and vice versa. The equation used to represent this would be F=m • a
This lab is related to Newton;s Second Law of Motion.

Real World: This lab relates to pushing a shopping cart at the grocery store. When you first walk in to the grocery store and grab an empty cart, it is easy to push because there is nothing inside. The force you exert would make the cart accelerate faster because of its low mass. However, after you are done shopping, the cart becomes harder to push because you have put many items inside. If you exert the same amount of force onto the full cart as you did to the empty cart, it would accelerate slower because of its higher mass.

Hover Disk--Interaction Diagrams

Purpose: The purpose of this lab was to test motion without the force of friction. We used a hover disk because it floats on a pocket of air, essentially allowing it to glide on a frictionless surface. We used Newton's 3 Laws to answer the Big Question, "What gives rise to a change in motion?" This lab focused on the different forces being applied to an object--force pairs. This lab is summed up in Newton's Third Law.

How?: In this lab, the object we applied force to was the hover disc. First, we turned on the hover disc (removing friction) and pushed it across the floor to the other person. Then we repeated this with the hover disc off, which added the element of friction. After completing these motions, we looked at the interaction diagrams and filled in arrows to each object which represented the type of force being used.

Conclusion--Interaction Diagrams: As you can see in the two diagrams below, the Force of Gravity (pink) and Normal Force (purple) are ALWAYS present between the earth, the two people, and the hover disc. The Normal Force is only present between the person and the hover disc when they are in contact. Also, notice that once the hover disc was turned off, the Force of Friction (blue) is now added between the hover disc and the earth.

Real World: An example of this lab would be comparing ice skating to walking. When we walk, the Force of Friction is present between us and the ground (hover disc off). This force enables us to keep a steady pace and firm footing on the ground, because without it, we would glide on forever instead of walking. However, ice skating is a little different. Since ice skaters are on blades as well as a slick ice surface, there is less friction between the person and the ice, enabling them to glide smoothly over the surface.

Impulse

Purpose: In this lab, we explored the new concept of impulse, and used our data to answer the Big Question, "What is the relationship between impulse, force and time?" This lab is connected to our previous collision lab, and we found impulse by going off of our knowledge of momentum.

How?: We started this lab the exact same way we started the last one, except on one side of the track we had a Logger Pro to record the car's velocity and a Force Probe Ring of the other side. We measured the car's velocity before and after the collision, and also measured the area of the dip in the "Force vs. Time" graph.

Graph: We used the velocity we collected to help us calculate momentum, "P".
We needed to find the momentum before and after the collision to find impulse, "J".
Impulse=ΔP
J=Pf - Pi

Conclusion: The area of the dip in our "Force vs. Time" graph was about -0.3613.
Our calculated impulse was -0.301. The impulse is about equal to the area. This is an example of Newton's Third Law of Motion--"For every action, there is an equal and opposite reaction." The concept of impulse is the relationship between force, time and momentum.

Real World: This lab relates to the popular middle school game, "Wall Ball." When a kid hits the ball against the wall, it comes back to the other player with an equal amount of force and momentum.