Keywords: IGCSE Prescribed Practical, Speed of Sound, Resonance Tube, Physics, Wavelength, Frequency, Air Column, Resonance, Sound Waves, Experiment

Introduction: In this IGCSE Prescribed Practical experiment, we will measure the speed of sound in air using a resonance tube. Sound travels in the form of waves through different media, and its speed varies depending on the medium. Understanding the speed of sound is essential in various fields, such as physics, engineering, and acoustics. In this experiment, we will create a standing wave in a resonance tube and use the wavelength and frequency of the wave to calculate the speed of sound in air.

Equipment Needed:

Resonance tube Tuning fork or speaker with known frequency Ruler or measuring tape Water Rubber mallet (if using a tuning fork) Step by Step Method:

• Fill the resonance tube with water, ensuring that it is almost full but not overflowing.
• Strike the tuning fork with a rubber mallet or turn on the speaker to produce a sound with a known frequency (f).
• Hold the vibrating tuning fork or speaker above the open end of the resonance tube.
• Slowly lower the water level in the resonance tube by opening the valve or carefully pouring out the water or by raising the resounance tube out of the water.
• Listen for a change in the loudness of the sound. The sound will be the loudest when a standing wave is created in the air column inside the tube.
• When the sound is loudest, measure the distance (L) between the water level and the open end of the resonance tube.
• Calculate the wavelength (λ) of the standing wave using the formula: λ = 4L.
• Calculate the speed of sound (v) in air using the formula: v = fλ, where f is the known frequency of the tuning fork or speaker.
• Repeat the experiment for increased accuracy and calculate the average speed of sound.

Expected Findings and Calculations: In this experiment, we will calculate the speed of sound (v) in air using the frequency (f) and wavelength (λ) of the standing wave created in the resonance tube. The formula to calculate the speed of sound is: v = fλ.

Conclusion: By conducting this IGCSE Prescribed Practical experiment, you will be able to measure the speed of sound in air using a resonance tube. Understanding the speed of sound is crucial for a variety of applications in physics, engineering, and acoustics.

Questions:

1. What is a standing wave?
2. How do you calculate the wavelength of a standing wave in a resonance tube?
3. What is the formula to calculate the speed of sound in air?
4. Why is it important to repeat the experiment for increased accuracy?
5. What factors can affect the speed of sound in air?

Answers:

1. A standing wave is a wave that is stationary and does not propagate through space. It occurs when two waves with the same frequency and amplitude travel in opposite directions and interfere with each other.
2. The wavelength of a standing wave in a resonance tube can be calculated using the formula: λ = 4L, where L is the distance between the water level and the open end of the resonance tube.
3. The formula to calculate the speed of sound in air is: v = fλ, where f is the frequency of the sound wave and λ is its wavelength.
4. Repeating the experiment for increased reliability helps account for any inconsistencies or errors in the measurements, providing more accurate results.
5. Factors that can affect the speed of sound in air include temperature, humidity, and air pressure.

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