Why Is My Calculated Speed of Sound Incorrect?

AI Thread Summary
The calculated speed of sound using an ultrasound emitter was found to be approximately 624 meters per second, which is significantly higher than the known speed of sound at 337 meters per second. The user correctly calculated the distance as 6.8 meters for the round trip but questioned whether the time measurement was accurate. There is a possibility of misunderstanding the time conversion from microseconds to seconds, as well as potential issues with ultrasound reflections affecting the distance measurement. Clarification on the time and distance parameters is needed to resolve the discrepancy. Accurate measurements and calculations are crucial for proving the speed of sound in this experiment.
Astonix
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Homework Statement



We have to prove the speed of sound using a ultra-sound emitter, connected to EasySense software which records the speed for it to travel to surface and back. Known data - Speed of sound is 337 metres a second at 20 degrees celcius. Also, the distance covered is, 3.4m or 6.8m there and back. The time is 0.010837 micro seconds. Micro-seconds are 1 x 10^-6. All answers must be given with a +- .

Homework Equations



Speed = Distance / Time

The Attempt at a Solution



Time: 10897 +- 14 (microsecs)
Dist: 6.8 +- 0.014 (metres)

Convert microseconds into seconds. 10897 / 1000 and then /1000 again.
= 0.010897 seconds

Speed = 6.8 / 0.010897 = 624.024961 metres per second.

Obviously, this is nearly double the actual speed of sound. Was I not meant to double the distance? But I'm pretty sure the time is for there and back so double distance was needed. Have I forgotten anything? Of course, there is a chance the Ultrasound was reflecting from a place not wanted, causing the distance to not be true.

Help much appreciated.
 
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Astonix said:

Homework Statement



We have to prove the speed of sound using a ultra-sound emitter, connected to EasySense software which records the speed for it to travel to surface and back. Known data - Speed of sound is 337 metres a second at 20 degrees celcius. Also, the distance covered is, 3.4m or 6.8m there and back. The time is 0.010837 micro seconds. Micro-seconds are 1 x 10^-6. All answers must be given with a +- .

Homework Equations



Speed = Distance / Time

The Attempt at a Solution



Time: 10897 +- 14 (microsecs)
Dist: 6.8 +- 0.014 (metres)

Convert microseconds into seconds. 10897 / 1000 and then /1000 again.
= 0.010897 seconds

Speed = 6.8 / 0.010897 = 624.024961 metres per second.

Obviously, this is nearly double the actual speed of sound. Was I not meant to double the distance? But I'm pretty sure the time is for there and back so double distance was needed. Have I forgotten anything? Of course, there is a chance the Ultrasound was reflecting from a place not wanted, causing the distance to not be true.

Help much appreciated.

You have very different times in 1 and 3 above. Could you also have misunderstood the distance?
 

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