Speed of Sound Calculations. Confused.

In summary, the conversation revolves around proving the speed of sound using an ultra-sound emitter and EasySense software. The known data includes the speed of sound at 337 metres per second at 20 degrees Celsius, and the distance covered is 3.4m or 6.8m there and back. The time recorded is 0.010837 microseconds, and the equations used are Speed = Distance / Time. However, after calculations, the result is nearly double the actual speed of sound, leading to confusion and the possibility of incorrect distance measurements. Further assistance is needed to determine the accuracy of the experiment.
  • #1
Astonix
2
0

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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  • #2
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?
 

1. How is the speed of sound calculated?

The speed of sound can be calculated using the formula v = √(γRT), where v is the speed of sound, γ is the adiabatic index of the gas, R is the universal gas constant, and T is the temperature in Kelvin.

2. What factors affect the speed of sound?

The speed of sound is affected by several factors, including temperature, humidity, altitude, and the medium through which the sound is traveling. These factors can change the density and compressibility of the medium, which ultimately affects the speed of sound.

3. Why does the speed of sound change with temperature?

The speed of sound increases with temperature because as the temperature rises, so does the average speed of molecules in the medium. This leads to an increase in the medium's elasticity and a decrease in its density, resulting in a faster speed of sound.

4. How does altitude affect the speed of sound?

The speed of sound decreases with altitude because as altitude increases, the air becomes less dense and less elastic. This results in a decrease in the speed of sound, as there are fewer molecules for the sound waves to interact with.

5. What is the speed of sound in different mediums?

The speed of sound varies depending on the medium through which it travels. In general, sound travels fastest through solids, followed by liquids, and then gases. For example, the speed of sound in air at sea level is approximately 343 meters per second, while the speed of sound in water is about 1,500 meters per second.

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