Tuning Fork/Palm Pipe Lab

Over this past week, we have learned about sound and waves. We experimented with palm pipes. I used palm pipe #7 for our experiment.

To see what kind of sound this pipe would make, we needed to find the length, diameter, wavelength, and the frequency. 

Calculations:

length: 12.5 cm = 0.125m

diameter: 1.3 cm = 0.013 m 

wavelength: 0.513m

frequency: 668.62 hz

I input the frequency into Wolfram Alpha and found that my palm pipe's note is supposed to be E5 + 24cents.

We created our tune by hitting the end of the pipe with our hand. Then, when the noise was made, the microphone connected to the lab quest picked up approximately 0.03 seconds of sound. The peak was 625 hz as shown below on the lab quest. When I put the peak into Wolfram Alpha, it gave me "E♭5" which is very close to my calculation.

We learned that woodwind instruments are closed at one end and the harmonics are in odd increments. They are similar to stringed instruments since they are mathematically proportional and the fundamental frequency is always the lowest frequency at which a standing wave will occur. The harmonics look like this: 

Light & Optics Real World Connection

The image displays the difference between a real image and a virtual image. The image on the left displays each light ray converging, allowing the focus point to meet, which results in a real image. The image on the right shows the focus points not meeting, which displays a virtual image.

Magnetism

Standard 6.4: 

How can we use the R

ight Hand Rule #2 to predict how 

moving charges are affected by magnetic fields (the direction of the magnetic force on the moving charge)? 

The thumb points in the direction that the charged particle moves in.

The Fingers point in the direction of the magnetic field. 

The direction of the palm faces the direction of the force on a positively charged particle.

iPad Batteries

Real World Connection

This week, we learned about voltage and how it is used in our lives, so for homework we had to research more about iPads.

Voltage (electric potential) is defined as a field that surrounds charged objects.

iPad battery:

The battery is an interchangeable, rechargeable lithium-polymer battery. (http://www.apple.com/batteries/ipad.html)

It is also supposed to last 10 hours until it is necessary to charge again. To charge the iPad, a charger with 10 Watts and an output of 5.1 Volts is required. 

Nothing has been release about future works on iPads, but sources speculate that it will probably be able to charge faster (energy will be transferred faster), and the new technology doesn't have the ability to overheat the iPad while it is charging, even if energy is being transferred.

Projectile Motion Lab

This week, we went down to the gym to shoot basketballs and use the Vernier Video Physics application on our iPads to observe the projectile motion. Projectile motion is when an object is only acted upon by force of gravity.

The Vernier Video Physics app made graphs for the x component and y component:

x (position and velocity)

In the top graph, the slope is constant.
In the bottom graph, the line is relatively constant without a slope.
Since there is no slope, there is no acceleration, so there is no net force

y (position and velocity)

In the top graph, the slope is not constant so it is accelerating.
In the bottom graph, the slope is negative, and the graph should intersect the x axis.
The line shows the path of the object, in this case, a basketball going up, and when it crosses the x axis, it stops (time = 0) and begins to fall down.
There is a slope so there is acceleration.

Then, as our table combined the graphs, we came up with an average slope of -10 m/s^2. We collectively agreed that acceleration is due to gravity.

Forces in 2D and Circular Motion

                                        

What does it mean to analyze forces in 2D?

To measure both the x and y components. Once the forces are broken up into both the x and y components, we use SOH, CAH, or TOA to find the magnitude of Fx and Fy. then we can find Fnetx and Fnety.  

How do forces cause objects to move in a circle? 

As an object moves in a circular motion, it changes direction. An object moving in a circle is accelerating. It accelerates because the direction of the velocity is constantly changing. The net force acting upon an object is facing towards the center of the circle. The net force is acting as a centripetal force. Without net force, an object would continue to move in a straight line. In our lab, we tested this force by attaching a string to the hover disk. We spun the disk around and felt the inward force as the disk was hovering around us. When released the string, the hover disk glided in a straight line because there was no centripetal force acting on it. 

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

To be in orbit means to be traveling around another object, such as the moon. Satellites orbit because of the gravitational pull of Earth. Since the planet is rotating and since the satellite is free falling, the satellite will move sideways and fall into the orbit of the planet. Just as the moon orbits the Earth because of the earth's gravity, the Earth orbits the sun because of the pull of the suns' gravity.