However, there were a few sources of uncertainty with this experiment. First, there are most likely different types of each material, which may produce different outcomes. For example, in this experiment steel was used for the metal and oak was used for the wood, but the outcomes might have been different if different types of metal and wood were used (iron, maple). Also, the insulated boxes/cylinders were made from of card stock poster paper, and very little sound most likely went through the card stock instead of the material. If a different material such as cardboard or plastic were used for the insulated boxes/cylinders, even less sound would likely have traveled through them. This would leave more sound to travel through the actual material, resulting in a more accurate outcome. In addition, the sound source that was used was at the loudest volume that an iPhone can reach. However, if quieter sounds or even sounds with different pitch were played, the results might remain the same but outcomes may be different.
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Source of uncertainty In the hypothesis, it was predicted that the metal would lose the most intensity of a sound wave. This hypothesis was verified by the results shown from the average of the trials. |
Validity and Reliability
This experiment has high validity. The initial aim was to discover which material allows the least intensity of sound waves to pass through it, which the results successfully revealed. The results, therefore proved the hypothesis and as an outcome, the most effective material at blocking sound was found (metal). These results can be used to benefit society.
This experiment is proven to be reliable due to the fact that the intensity of the sound waves passing through the materials in all three trials, stayed within 2 decibels of each other. This indicates that the experiment is consistent. Also, the average of the three trials for each material was the same as one of the trial results for that material. This indicates that the experiment consistently produced the same results.
This experiment has high validity. The initial aim was to discover which material allows the least intensity of sound waves to pass through it, which the results successfully revealed. The results, therefore proved the hypothesis and as an outcome, the most effective material at blocking sound was found (metal). These results can be used to benefit society.
This experiment is proven to be reliable due to the fact that the intensity of the sound waves passing through the materials in all three trials, stayed within 2 decibels of each other. This indicates that the experiment is consistent. Also, the average of the three trials for each material was the same as one of the trial results for that material. This indicates that the experiment consistently produced the same results.
Further Investigation
Although this experiment was accurate and had testable results, there are improvements and further questions to be asked. For example, the insulated boxes/cylinders of some of the materials weren't 100% tight around the materials. This left room for air bubbles, which could have affected the outcome of the intensity result. In addition, the wool was not a solid object, so there was most likely air left in the insulated box/cylinder. A good alternative to this would be using solid wool or even fabric that is not 100% wool. Other fabrics could be tested in this experiment as well because different fabrics have different densities. To prevent air bubbles in future experiments, using more solid objects than card stock for the insulated boxes/cylinders would help materials fit more tightly in the boxes/cylinders. Lastly, another improvement could be using a real decibel meter rather than a phone app because not all apps are accurate and trustworthy.
Some further questions that came up during the experiment:
-Does the pitch of the sound source affect the loss of intensity of sound waves?
-If the sound source is farther away from the materials would the outcome be affected?
-Does the volume of the sound source effect the results?
While doing this experiment, idea of future studies came up. For example, instead of physically conducting this experiment, the problem could be tested using the formula for intensity to find out how accurate decibel meters are:
B=(10dB)log(I/Io)
where B=intensity in decibels
where Io=intensity of threshold
where I=intensity of sound after it has been passed through a material
Using this formula, further tests could be run to see how accurate decibel meters are compared to the formula.
Other experiments could include changing the pitch, the volume of the sound source, and the distance from the sound source to the material.
Lastly, another experiment could be finding materials with a higher density than metal and testing if they are better insulators.