Introduction
In this science experiment, we will be using sound to measure temperature. To perform this, we will measure the air temperature inside a pipe by measuring the speed of the sound.
Aim
To measure the air temperature inside a pipe by measuring the speed of the sound.
Theory
1. At a higher temperature, the air molecules have much energy to vibrate faster. Therefore, at higher temperatures, the speed of sound increases.
2. Speed of sound in air is directly proportional to the temperature of the air.
An Oscilloscope
Requirements
1. Microphone
2. Speaker
3. Oscilloscope
4. Thermometer
5. Audio Generator
6. Hairdryer
7. 3.6-Foot Long Pipe
8. Scale
Procedure
Step 1: Take a pipe. Place a speaker and a microphone at each end of the pipe.
Step 2: Measure the length of the pipe by measuring the distance between the speaker and the microphone.
Step 3: Combine the equation v = 331 + 0.6T and v = d/t, where d = 1.1 meters and t = temperature measured in degree celsius, to find the lag between the speaker’s input and output for the temperature from 0 to 100-degree celsius.
Step 4: The above two equations combine to create a new equation d/t = 331 + 0.6t.
Step 5: Calculate the time taken by the sound to travel through the pipe at 0 degrees Celsius.
Step 6: Calculate the time taken by the sound to travel through the container at 100 degrees Celsius.
Step 7: Subtract these two times and divide the obtained number by 100.
Step 8: Using a hairdryer, heat the air in the pipe to the desired temperature, and turn on the sound waves.
Step 9: On the oscilloscope grid, mark the intersection of the wave immediately after the use of a hairdryer.
Step 10: Add one-degree Celsius for every 5 microseconds of lag,
Step 11: Now, calculate the temperature and the result with the thermometer.
Step 12: Repeat the procedure just after the pipe cools down.
Observation
1. From this experiment, we observed that on repeating the same experiment 10 times, the calculated and the actual temperature differed by an average of 2.8 degrees Celsius.
2. The average percentage of error in this experiment was 4.89%.
Result
1. We accurately predicted the temperature by the velocity of the sound that passed through it.
2. On increasing the temperature, speed increases. And as the air cools down, speed decreases.
3. This is due to the fact that at a higher temperature, there is more energy in the air. And with more energy, particles vibrate faster, which increases the speed of the sound.
Precaution
1. Repeat the experiment only after the pipe cools down.
2. Calculate the temperature carefully.
3. Pipe should not be longer than 3.6 feet.
Conclusion
In this experiment, we determined the air temperature by using the fact that the speed of sound depends on the temperature of the air.
VIVA Questions With Answers
Q.1 What was the aim of your experiment?
ANS. To measure the air temperature inside a pipe by measuring the speed of the sound.
Q.2 How does the speed of sound depend on the temperature?
ANS. The speed of sound is directly proportional to the temperature, which means on increasing temperature, the speed of sound increases, and on decreasing temperature, the speed of sound decreases.
Q.3 What was your percentage of error?
ANS. The average percentage of error in this experiment was 4.89%.
Q.4 Why does the speed of sound increase with increasing temperature?
ANS. This is due to the fact that at a higher temperature, there is more energy in the air. And with more energy, particles vibrate faster, which increases the speed of the sound.
Q.5 How much was the difference between your calculated and measured temperatures?
ANS. The calculated and the actual temperature differed on average by 2.8 degrees Celsius.
Saquib Siddiqui is a Mechanical Engineer and a content creator. He has special interest in science experiments and teaches the same to school and college students. He is also a technical lead at RUDE LABS PVT. LTD.
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