Tuning Fork and Palm Pipe Lab

In class we experimented with the tuning forks and palm pipes and learned the physics behind why they produce certain notes.

Tuning Forks:

Hitting the tuning fork against my shoe caused it to vibrate at a certain frequency. By finding out this frequency we were able to determine what note it was playing. We recorded this by placing the microphone plugged in to the lab quest next to the fork. We were then able to analyze the data by reading the graph. The peaks were evenly spaced which shows that it is a harmonic. This means that there are multiples of the fundamental frequency. A fundamental frequency, also called the 1st harmonic, is the lowest possible frequency that makes a standing wave.The tuning fork's vibrations react to the air around it which causes it to make a sound. This explains why certain musical instruments sound different from each other even while playing the same note. Music is actually mathematical and occurs because it is promotional, while noise is just random.


Palm Pipe:

For this lab everyone was given a pipe (sizes varied) and we had to find what note it produced when hit form one side. We started by measuring the pipe and then finding the diameter. I made sure to only measure the part where the air would be moving through instead of the extra plastic around the sides. We were given the equation of length=1/4wavelength - 1/4diameter. Once we found the wavelength we could plug it into our other equation: 343m/s=(wavelength)(frequency). By finding the frequency we could then put in into wolfram alpha to see what note it played.

Light and Optics Photo

This is the picture I created using a flashlight and cup of water. I think that it is really cool that rainbows occur naturally, but they can also be created artificially. To do this I pointed the flashlight at an angle towards the water to get it to reflect a rainbow on the table. This worked because the reflection of light in water results in a spectrum of light appearing. It shows up in colors because the light is first refracted going through the surface of the water, reflected off the back, and then refracted again as it leaves the water. The amount of light that is refracted depends on its wavelength, which gives it its color. Certain colors have shorter wavelengths than others so this is why we can differentiate the colors from one another.

Standard 6.3

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

The earth is like a big magnet. The core is made out of metals(because dense elements sink) and the outer core is molten, ionized metals. Because it is metal it conducts, meaning that charges flow easily. Earth is also moving and spinning so it increases movement of charges. The moving charges in the outer core generate earths magnetic field.

There are three types of magnetic material: Non magnetic(no domains), magnetic material(domains but not lined up), and magnet(domains all lined up). A magnetic domain is a group of atoms aligned so that their magnetic fields add together to make a stronger field. Electrons have tiny magnetic fields because they are charged and spinning.

Lemon Lab-Real World Connection

                               











http://www.apple.com/batteries/ 

This week in class we learned that voltage is a field surrounding charged objects and electric potential energy is Ue=charge(voltage). Voltage is like a mountain or altitude(or like the "gh" in Ug=mgh). We were able to make a battery out of a lemon because its acidic nature is like the acidic solution in regular batteries and we also stuck a penny(- charge) and a nail(+ charge) into opposite sides to conduct electrons. This is relevant to the world today because the battery has not changed much since it was first invented. Our lemon battery didn't have very much voltage but it can be compared to the iPad battery because they both have the same basic science behind them. I went to the apple website to find more information about the batteries. The batteries that power our iPads are lithium-ion polymer. I learned that they are designed to work in a certain charge cycle to maximize the battery life. They have a high-power density but it is very light. These special charge stages have to do with voltage and charge current, which is described in this chart:

Projectile Motion Reflection

What is a projectile? What is the general path of motion? Why?

A projectile is a moving object with gravity being the only force acting on it. If there was any other force acting on the object then it wouldn't be considered a projectile. To further understand this, we shot basketballs and tracked their movement using the video physics app. We started tracking the ball at the moment it left our hands and ended it when it touched the ground. Our basketball moved at constant speed in the x direction while accelerating in the y direction. Even though it accelerates in the y direction, the x is constant so we know that the slope is also a constant. At the balls highest point on the graph it is actually not moving. It reached its peak and now it starts to move downward. 

Our free body diagram shows that the only force acting on the projectile is Fg. It doesn't matter whether a projectile is moving downwards, upwards, upwards and rightwards, or downwards and leftwards the free body diagram would look the same. 

These are my graphs:

Forces in 2D and Circular Motion

1. What does it mean to analyze forces in 2D?

2D stands for two dimensions of space. We can analyze these dimensions separately or individually from one another. This means that it has an x and y coordinate, as opposed to a 4D universe which we live in that has 3 dimensions of space and 1 dimension of time(x,y,z,t). Analyzing a force in 2D means that we need to find a height and length. A force in 1D would only have height, and a force in 3D would need to have height, length, and some kind of curve.

2. How do forces cause objects to move in a circle?

Forces cause objects to move in a circle due to their center pointing(centripetal) net force. When an object is moving in a circle, it is accelerating. Not because its speed is changing, but because its direction of motion is changing. In order to accelerate, it must be experiencing an unbalanced force(net force).


3. What does it mean to be in orbit? How do satellites orbit planets? How do planets orbit the sun?


To be in orbit means that an object follows a path revolving around another object. The gravitational force is the centripetal force, and the pull keeps the object in orbit from floating away(because there is no friction in space). When satellites orbit they are really falling to the earth. Because of gravity they actually end up moving sideways around the earth. Planets orbit around the sun in a circular motion, similar to that of the satellites around the earth.

Newtons Three Laws of Motion

Law #1: If an object is at rest or in motion at a constant speed, it will stay that way unless it experiences a net force.

Law#2: Force equals mass times acceleration, F=ma. Mass and acceleration are indirectly proportional.

Law#3: When two objects interact they exert equal but opposite forces on one another. They feel a force that is...

• The same type(typically normal, friction, or gravitational)
• The same amount(no matter how big or small, the force felt is the same)
• Opposite

Hover Disk Lab

Big Question-What gives rise to a change in motion?

The purpose of this lab was to learn which forces are pulling on certain objects, in this case two people, the ground and a hover disk, by knowing Newtons 1st and 3rd laws. We experimented with a hover disk and learned that it blows air out from the bottom to eliminate friction, allowing it to glide on smooth surfaces. Theoretically if you pushed the disk, and if the surface was infinitely smooth(and if there is no air resistance), it would glide in a straight line forever. For a while we played around with the disk and passed it along to one another, simulating the diagrams in our worksheet. We used interaction diagrams and free body diagrams to chart the forces acting on each individual object. 

In this diagram the disk is on but at rest and has not been pushed yet. The earth has a normal and gravitational force with each object, yet none of the objects are interacting with each other at this time. Its strange to think that the earth and person 1 are feeling the same force from each other but it is true!

We also drew a free body diagram as a second way to show the force between each object

involved.The arrows are vectors that represent the forces acting on the disk. 

This is another diagram we drew, but this time the hover disk is on and being caught by person 2. This is different from the first diagram because the disk and person 2 are now interacting. They have a normal force acting upon them.

Fan Cart Lab

Big Question- What is the relationship between force, mass, and acceleration?

From this lab we learned that F=ma. This means that if the mass increases then the acceleration decreases(and vice versa), to equal the force. In other words, the net force on an object is equal to the mass of the object multiplied by its acceleration. This is proven by the data we collected. Although trial 4 does not fit the pattern, we concluded that this was due to human error. 

As you can see trial 4 is the outlier, so we calculated the percent error to find out our mistakes. 

Real World Connection

I found this video about Newton's Laws of Motion applied to everyday life. I liked how it had multiple examples to show just how common these theories are in the real world, not just in the classroom. In the video it showed a game of pool. The ball would remain still and at rest unless an outside force pushes it.  Once hit, the balls move in the direction that they are expected to depending on the angles that they are hit at. It was interesting for me to see that something as simple as pool can relate to physics.

http://videos.howstuffworks.com/discovery/29421-assignment-discovery-newtons-laws-of-motion-video.htm