GSoC Weekly Report 6

The previous week ( From Monday 23rd to Sunday, 29th June 2014) we could setup some new experiments to study the phenomena of Friction and sound.

Submitted the midterm evaluation on June 25th. On 28th midnight at 12.45 am…..got the happiest news that I have successfully passed the Google Summer of Code 2014 – Midterm Evaluation….. awesome moment I was waiting for….. Thanks a million to my mentors for all the guidance, help and encouragement.

Also received message from Payoneer that they have processed my GSoC payment. Now I can order some equipments Like Audio Frequency Oscilloscope and amplifiers for my Project. These equipments will help me to try the experiments and achieve the same with ExpEYES later.

Things We Could Do….

• Setup an experiment to obtain Lissajous Figures using Square waves with various values of phase difference. Repeated the experiment with sine waves. Phase difference can be added with a capacitor and resistor circuit.
• Started working on an experimental setup to produce these pattern in 3 Dimensions using Laser and Speakers.
• Submitted the midterm evaluation report.
• Completed the  set-up of a mechanics experiment to study conservation of momentum.  Wrote  python code to get the data.
• Designed an instrument using  a  pulley and a photo-gate to measure acceleration. ( thanks to open educational resources for the idea..)This can be used  for different experiments involving friction.
• In an experiment  to study oscillations of a loaded spring, we could obtain position time data and plot graph.To determine the spring constant of the given spiral spring we need to measure frequency and time periodic time.I could get this done by fitting the data by using a python code.
• Set-up for demonstration of Doppler effect is ready. I used A buzzer attached to a spiral spring and made it oscillate in-front of the mic.
• Prepared the experimental set-up For Doppler Effect. I have used the linear air track and fixed the source of sound on the glider. the emitted sound waves can be detected by a microphone fixed in ExpEYES. We can determine the original frequency of the source using ExpEYES and then the source is set in to motion and again frequency is determined.  A photo-gate is used to measure the speed of the source.
Things To Do Next Week….
• GUI for experiments with Friction
• GUI for Doppler Effect
• Documentation for all these Experiments
• Python Code for a separate GUI for Plotting data from all channels of ExpEYES.

Sunday, 29th June 2014

Since yesterday I am working on setting up of an experiment to study Doppler effect in sound.

If the source of sound or the detector is in motion relative to the medium of propagation, the frequency of the waves that are emitted  appears to be changed due to Doppler Effect. This is an interesting experiment at Higher Secondary level.

The experimental set-up is ready. I have used the linear air track and fixed the source of sound on the glider. the emitted sound waves can be detected by a microphone fixed in ExpEYES. We can determine the original frequency of the source using ExpEYES and then the source is set in to motion and again frequency is determined.  A photo-gate is used to measure the speed of the source.

The apparent frequency is related to the speed and the original frequency. The experimental results can be verified by theoretical calculations.

Practical Application:

1. General Study of Doppler Effect
2. For different frequencies, measure the Doppler shift with different velocities of the sound emitter. Compare the theoretical and experimental results.

The python code required for measuring frequency and also to determine speed using photo-gate  is already written. I could get good results in my experimental trials.

Tomorrow I will work on developing a separate code for a simple GUI for this experiment.

Saturday, 28th June 2014

Today I started working on an interesting experiment in sound and Waves. It is very  difficult to do experiments involving Doppler Effect in conventional laboratory. But with the help of ExpEYES Doppler Effect can be Demonstrated very easily.

The experimental set-up for demonstration of Doppler effect is ready. We need a moving source relative to the detector. Detector is the simple mic inside ExpEYES. For getting  a source which is harmonically oscillating, I used A buzzer attached to a spiral spring and made it oscillate in-front of the mic.

First, the frequency of the emitted signal is measured at rest. Then, the frequency shift that is caused by the oscillating source is measured. this can easily demonstrate ‘the apparent change in the frequency due to Doppler Effect.

My next step is to develop a set-up to measure Doppler Shift in case of a moving source with constant velocity. For this I am planning to use my linear air track which is developed for mechanics experiments, so that the cost can be reduced.