variables

[homeschool513]

My son is trying to blow out a candle using sound waves. He did some research and knew that it had been done before. His hypothesis is that rock and roll music can blow out the candle. This project required some trial and error on his part. During different phases, he had to change different variables. How does he show this experimentation?

He started by using the same size/brand candles and the same song, but changed the speakers. He started with old basic speakers. Then he used a new boom box with bass boost. Finally he had help from a musician friend and used large speakers with a mixing sound board.

Once he had the larger speakers, he had to experiment to test at what angle he should place the speakers for maximum effect. So again he kept the candle, music, speakers and power output the same, but changed the angle of the two speakers.

Finally, kept all the above variables the same and tried different songs to see if he could reproduce the effect with other rock and roll music.

Should he show all the trial and error even though he had to keep changing the variables in each step? This does show the time commitment he placed in the project. Or should he only show the final steps where he was comparing the different music?

Thank you so much for your input.

Laura

[deleted-71588]

What you described in terms of experimental proceedural changes "sounds" like (pun intended) brute force trial and error in the absense of a hypothesis. Not sounding very sientific to me...

Your son needs to back up and re-read (hopefully he read it earlier before he started), the "Scientific Method" in the Science Fair Project Guide area.

There are all sorts of variables involved, does he understand them well enough to talk to a science fair judge about them?

There is an applicable "Engineering Methodology" aspect to what he apparently did. This is slightly different than the "Scientific Method". Engineering methods to solving problems involve the statement of the problem, some usually some "cost function" for evaluating competing solutions (choose the one with the lowest cost basis). This methodology then goes on to come up with a measurement scheme that is used to evaluate any trials. The measurement scheme has to be something beyond a binary yes/no result.

In your son's case, some evaluation of how much flame flicker occurred might have been a predictor on whether there was an improved or reduced chance of blowing out the candle.

Because the last variable being altered was speaker angle, there final result involved some phase angle between left and right speakers. Was the sound source for the speakers mono or stereo?

Was sound power measured? Was distance from the speaker measured? Were room reflections controlled in some way? Was frequency measured (an experienced musician can tell you what musical note was involved and this can be looked up to figure out what frequency was involved).

I'm sure there are several hypothesis that could be constructed and then investigated scientifically, but were they? With the knowledge that your son currently has, does he have time to construct a scientific experiment and perform the trials and get his result? If not, then he may not have much in the way of science to report.

Sorry if this sounds harsh. It doesn't matter how much effort somebody puts into something if what is being evaluated is a science experiment and there is no scientific basis (reasonable application of a scientific method for evaluating a hypothesis) involved. Junk science is junk.

On the other hand, if you son started out with a hypothesis and got a non-result, that is "good science". Starting out to prove or disprove a hypothesis is not a gaurantee that the outcome might not be "this method can't determine the result". Your son could have stopped at that point and prepared the report. If that was the first result, then his final report should reflect that. He did an experiment and got a result. If that was the case, then any further work to come up with something that works and the knowledge gained is VERY appropriate as an add on to the original experiment. Science often leads to follow on work. Even better if an altered hypotesis was stated at each step in the alteration of the methods used (or in retrospect could be stated). That would be GREAT science. Hope he kept good notes in an engineering or science notebook. That is Critical to doing good engineering and science. Even if the notebook did not contain the altered hypotesis at the time, DO NOT ALTER THE NOTEBOOK, that aspect can be handled in the report after the fact if the notes of what was changed and the results were clearly documented. From good documentation, it is clear what the intent of the futher investigation was in retrospect and it can easily be handled in the report discussion.

More than half of the effort is in taking notes, evaluating, and writing up the results.

No mater what, I hope you son learns from this experience in a positive way on how to do a better science project in the future.

[homeschool513]

Thank you for your help.

My son is using the simple hypothesis "rock and roll music will be able to extinguish a candle". His reasoning is that the lower notes of the drums create larger sound waves. He did research on others who had done sound and fire experiments before attempting his own. In his first attempts at home, we were not able to measure things. It was truly trial and error, but when he involved his uncle, he was able to do this. He kept detailed records of the size and type of speakers. His uncle helped him use a sound board to keep the music level at the same place so he wasn't changing the size of the sound waves by volume instead of the actual wave frequency. His uncle was able to tell him within a range of hertz, which ones extingished the candle. He measured the distance of the candle from the speakers and the angles. He made adjustments to the candle holder as the candle burned so that the flame remained at the same height. He researched double slit theory with waves to learn that there is a "sweet spot" where the waves from the two speakers meet and create a more powerful effect.

This is why I wondered if we should include the first attempts at home or not.

Again thank you for your help.

laura

[tzforbes]

Laura,

It sounds like your son has been doing a lot of work on this project! I have been a judge several times for the local science fair and one thing I have seen is that students will have a poster board really highlighting the important points of the research (the hypothesis, the experimental set-up, the results, and the conclusions) and then have a secondary binder that contains additional information (such as the trial and error details, maybe some more pictures). Usually it is a three ring binder that the judges can flip through as they are talking to your son. I think this set-up may work well for your situation as your son has obviously done a lot of work and it would be nice to show that.

Tori