# Tuesday, 5th August 2014

Experiment to obtain Chladni figures is complete with the experimental set up and also the python code access the experiment.

This is the set up we designed and used ……

But It needs to be modified using a loud speaker as vibrations with the inductance coil are not large enough.

Also worked on giving finishing touch to python code of few experiments.

# Monday, 4th August 2014

Since yesterday, I am working on giving finishing touch to the programs written so far. To meet all the goals of our project I must complete the Sound experiments part.

Ajith sir has designed a stand-alone variable frequency sine wave generator for my experiments and this will help me to complete almost all the experiments which we have mentioned in the proposal. We have also developed the experiments which are not mentioned in the proposal.

Today I have created a separate pages for few experiments. The page for coupled pendulums experiment is complete with the required information (Its Here).

# Saturday, 2nd August 2014

## Resonance of a cantilever

Today we could complete the set-up for this experiment. We used a plastic stick and bicycle wheel spoke as a cantilever beam.
A plastic disposable cup is attached at the center of a loudspeaker using  adhesive ( which can be removed easily). Then the cantilever beams are fixed on the top of  the cup using cello tape.

The speaker is connected to SQR1 and the frequency is gradually changed. when the frequency matches with the natural frequency of the beam it starts vibrating with large amplitude.

The variation of resonance frequency with length can be investigated by cutting sections off the end of the plastic stick.

This is the setup we used….

# Friday, 1st August 2014

Today I continued to work on sound and waves related experiments. Experiment to demonstrate Chladni Figures and resonance is almost completed.
Also wrote the necessary python program for these experiments.

# Thursday, 31st July 2014

Chladni pattern is a n interesting example of Simple harmonic Motion. Today I devised a setup to produce these patterns using ExpEYES.

In Chladni patterns, points in an object undergo SHM with varying amplitudes. There will be some points where amplitude of SHM is zero, called nodes. If Small particles (sand / rangoli powder) are spread on the plate, they  collect at the nodes, ie along lines where the amplitude of SHM is small.

For the experimental Set-up I used a CD as Chladni plate. SQR1 is connected to  a small inductor (a coil of wire with no magnetic core) and produces a sinusoidal magnetic field. This is then placed close to a small magnet attached to the plate, and so produces a sinusoidal force on the magnet.

Two small magnets are placed on the edge of the plate. The inductor is placed so its centre is directly beneath the magnets and as close as possible to the plate without touching it.

Used python program to change frequency of SQR1.

# Wednesday, 30th July 2014

Continued experimenting and exploring with coupled pendulums.

This link was of great help: Two coupled pendula

Today worked on python code for the experiment to generate waveforms, and now it is in its final form. Pushed the same to my GitHub repository.

Repeated the experiment in three different ways:

• When both the pendulums oscillate in phase

• When  pendulums oscillate out of phase

• When one pendulum is at rest while the other is given oscillations

Now writing a simple GUI to access the code and experiment related information.

# Tuesday, 29th July 2014

Oscillations of Coupled pendulum is an interesting phenomenon in Physics.

Two pendulum connected with a spring can be made to oscillate in different ways…

• Both oscillating in phase
• Both oscillating out of phase
• One at rest and other oscillating

Today I could complete the experimental setup as well as the required python code.

Here is the experimental set-up….

The waveforms generated using DC motors after amplification…

The waveforms show beats as theoretically expected….

The complete code is here…

# Monday, 28th July 2014

Today I completed the program for resonance experiments ( tomorrow I will take some more trials with mic as detector) and continued to work on python codes for working with sensors – ultrasonic and photogate.

Started finalizing experiments with photo-gates. I may need another two days to complete everything, code and documentation of experiments with photo-sensors.

# Saturday, 26th July 2014

Today I worked on  Resonance Experiments using speaker instead of tuning fork.

The experiments of resonator and resonance tube are generally performed with tuning forks. Since tuning fork produces very low intensity sound, it is not clearly audible and the frequency is fixed. therefore the length of the resonance pipe must be changed to adjust with the frequency of tuning fork.

We used a speaker connected to SQR1 of ExpEYES. frequency of SQR1 can be varied till we get sound of resonance. a wide range of frequencies is available from ExpEYES therefore it is easy to do this experiment with various sizes of tubes and resonators. We used a mic to study the amplitude.

Here is the experimental set-up

Wrote a python program to change frequency of SQR1 and to plot the frequency v/s amplitude graph. The program for frequency response study of pizzo buzzer was already available. Just made few modifications required for this experiment.

I did experimental trials with a measuring flask, plastic pipe, conical flask and a round bottom flask.  Resonant frequency is between 300Hz to 750 Hz which varies with length of tube and volume of resonator.

# Friday, 25th July 2014

In most of the mechanics experiments we are trying to plot multiple graphs ( position, velocity and acceleration or kinetic energy and potential energy etc.)  in one figure. In the figure the axis labels of two graphs are overlapping. These labels should have some spacing between them.

Today, while trying to solve this problem I got the information about tight-layout function from matplotlib (thanks to Google),

Here is the figure without tight-layout() function. The axis labels and titles are overlapped.

Sometimes it can happen that axis labels or titles (or sometimes even ticklabels) go outside the figure area, and are thus clipped. tight_layout() can prevent this and also adjust spacing between subplots to minimize the overlaps.

This figure is obtained using tight-layout() function…

Today I have gathered required apparatus for performing various experiments like resonance and oscillations. Next two days I will set-up almost all planned experiments for my GSoC project.