Calculating the speed of sound in water

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Discussion Overview

The discussion revolves around calculating the speed of sound in water containing various contaminants, including chlorine, chloroamine, fluorides, copper, and lead. Participants explore different methods for calculating this speed, considering both experimental approaches and theoretical calculations based on the density of the solution.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • Harini Krishna seeks assistance in calculating the speed of sound in water with specified contaminants.
  • Some participants inquire whether the calculation is intended to be experimental or theoretical, suggesting that the density of the liquid may influence the speed of sound.
  • One participant references a formula for calculating the speed of sound based on density, suggesting that the speed in contaminated water may be similar to that in pure water due to low impurity levels.
  • Another participant emphasizes the importance of temperature in determining density and thus the speed of sound.
  • There is a discussion about the potential ambiguity in the mixing of samples and how it may affect the final concentration and volume, which could influence the calculated speed of sound.
  • One participant provides a calculation based on the given contaminant concentrations, proposing a theoretical speed of sound of approximately 1492.7 m/sec.
  • Another participant notes that the differences in calculated speeds due to mixing methods are minimal, suggesting that the impact on the speed of sound would be negligible.
  • There is a call for more information from Harini Krishna to refine the question and clarify the situation for a more meaningful calculation.

Areas of Agreement / Disagreement

Participants express differing views on the impact of contaminants on the speed of sound, with some suggesting it remains similar to pure water while others highlight the importance of precise calculations based on density and mixing methods. The discussion remains unresolved regarding the best approach to take.

Contextual Notes

Participants note that the temperature of the water is critical for determining density, which in turn affects the speed of sound. There are also unresolved ambiguities regarding the mixing of samples and how that might influence the final concentrations and calculations.

Harini Krishna
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Hi,i want to calculate the speed of sound in water
Containing
Chlorine : 4mg/L in 1L distill Water

Chloroamine : 4mg/L in 1L distill Water

Florides : 0.5mg/L + in 1L distill Water

Copper : 0.005mg/L + in 1L distill Water

Lead : 1.3 mg/L in 1L distill Water

Can you please help in this?

Thankyou
Warm Regards
Harini Krishna
 
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Are you wanting to do an experiment to calculate it? Or are you wanting to calculate it based on the density of the liquid?

In the first case, there are several experiments demonstrated online, using a tube and a sound generator.

If it is the second case, does your textbook discuss how the density of the medium affects the speed of sound?
 
The formula for these situations can be found at Engineering Toolbox.

Speed of Sound
 
I would effectively consider it to be identical to the speed of sound in pure water, given how small the levels of those contaminants are.
 
cjl said:
I would effectively consider it to be identical to the speed of sound in pure water, given how small the levels of those contaminants are.
It adds up to a little less than 10mg of impurities dissolved in each 1,000,000mg of water.
Even if all of that were lead, it would still mass the same as water to within one part in 10,000.

But hey, that won't change the math.
 
Harini Krishna said:
i want to calculate the speed of sound in water
Containing
Chlorine : 4mg/L in 1L distill Water
Chloroamine : 4mg/L in 1L distill Water
Florides : 0.5mg/L + in 1L distill Water
Copper : 0.005mg/L + in 1L distill Water
Lead : 1.3 mg/L in 1L distill Water
Can you please help in this?

It should be sufficient to specify;
Chlorine : 4mg/L
Chloroamine : 4mg/L
Florides : 0.5mg/L
Copper : 0.005mg/L
Lead : 1.3 mg/L
Unless you actually meant mixing the 5 samples to make 5 litres of distilled water, which will dilute the concentration per litre in the final mix.

The temperature will be critical as it will change the density more than the dissolved species.

The speed of sound due to density can be calculated from;
Speed of sound, c = √ ( k / density );

Assume that for a density of 1.000000 the speed of sound is 1500 m/sec.
Then; 1500 = √ k ;
∴ k = 1500² = 2250000.

For the total dissolved species = 9.805 mg/litre;
c = √(2250000. / 1.009805);
∴ c = 1492.7 m/sec.
 
Baluncore said:
Unless you actually meant mixing the 5 samples to make 5 litres of distilled water, which will dilute the concentration per litre in the final mix.
The ambiguity did not escape me either.

Adding 4mL/L of Chloramine to a litre of pure water is not quiiiite the same thing as adding 4mL/L of Chloramine to a premade solution of 4mg Chlorine per litre of water.

Taking the OP at face-value, his/er method will end up with a volume of 1.01961L, whereas your method will lend up with a volume of 1.09805L, resulting in slightly different densities.

Either way, I'd still say we're talking on the order of 1 part in 10,000. At 1450m/s we're talking about less than 2cm/s difference in speeds. The distinction above brings that down almost another order of mag to mm/s.
 
Last edited:
@Harini Krishna
Yes, we can help you calculate the speed of sound from the numbers.
The result will not be meaningful unless you;
1. Describe the situation, so we know what is fixed and what changes are important.
2. Refine the question, so we can ask for all the numbers needed.
 

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