On Resonance and Sound

In contrast to our experiment last meeting (Calorimetry), we performed an experiment regarding waves this week. Specifically, we performed an experiment which demonstrated resonance, the increase in amplitude of vibration of a body due to the constructive interference of the driving force of the vibration’s frequency and the body’s characteristic frequency of vibration.

Using a resonance “tube” filled with water and a speaker of constant frequency on top of the tube, we looked for the water levels wherein the sound volume was at a maximum. These water levels correspond to the length of the tube that allowed standing waves to be set-up. Also, at these water levels, resonance was observed. By getting the average of the difference between the distance where resonance was observed, we were able to obtain the wavelength using ΔL=½λ. Finally, using v=fλ, we obtained the speed of sound in the tube.

The experiment was quite difficult because it required us to hold the speaker manually above the tube. It was tiring so we took turns doing it. Also, water from the tube unfortunately spilled on the floor which caused quite a mess. Apart from these, I thoroughly enjoyed the experiment because we had good group dynamics.

On Heat and Calorimetry

Entering the 103.1 lab, I saw a gas stove set up. Asking what it for, I found out that we would be performing an experiment on Thermodynamics.

I consider Thermodynamics to be my favourite subject in our General Chemistry courses (16 and 17). Unfortunately, I have forgotten quite a deal on the said subject, so it was nice to rekindle my interest in thermodynamics by performing a simple calorimetry experiment this meeting.

Basically, what we did was mix hot and cold water together and measure the enthalpy change (ΔH=mcΔT) to see that the heat lost by the hot water and the heat gained by the cold water were equal. It was quite an easy experiment, though numerous little niggles cost us time. For one, the balance used to measure the mass of the calorimeter was in the other room so we had to go back and forth between rooms (though this was remedied eventually), and a short brownout occurred which we had to wait out to be able to use the balance.

Overall, the experiment was quite a simple task to perform. Compared to the experiments in 102.1, this experiment was a walk in the park.

On Light Intensity

The second experiment we performed was all about light intensity. To cut the story short, it was a quick experiment, not taking up more than 30 minutes. It was a relatively easy task--- we simply measured the light intensity from a light source and a laser at different distances from the light source using a light sensor connected to labquest.

From the graph of light intensity vs. distance from light source, we observed an inverse square law; that is, the light intensity is inversely proportional to the square of the distance from the light source. This conclusion was obtained using data from the light source (not laser). The data we got from the laser showed that light intensity was constant even at great distances. It could probably be the case that the intensity from the laser was so high that very great distances would be called for to see the inverse square law.

We encountered minimal error, if none. I think our group had good dynamics because we finished the experiment in record time. I hope that the next experiments are going to be as easy as this, so that we would always finish ahead of time. :D

On the First Meeting: Physics 103.1

Now that Physics lab meetings are on Mondays for this sem, I don’t think I’m going to be as stressed as I was last sem. I think that it is a good idea. Anyways, let me narrate what transpired on our first meeting.

The first Physics 103.1 meeting was quite “chill”, for lack of a better word. We didn’t perform any experiment or any hectic task. What happened, though, was Sir Baldo telling us the new things in store for us--- the experiment reporting (in lieu of the quizzes we had last semester) and the consequences for late submissions. Also, he shared to us some info about our lecture professors.

This was also the meeting where we finalized the groupings for the experiments. For Physics 103, my groupmates are Mac Aydinan, Reggie Bernardo and Julia Negre. Overall, I think that it is an excellent group. I don’t think communication is going to be a problem at all.

I’m quite excited for Physics 103.1, primarily because there are no circuits (which I hate) involved in this lab class (I think).