You carried out an experiment to measure the speed of sound in air by measuring the frequency and wavelength of a sound wave - Leaving Cert Physics - Question 3 - 2011

To find the frequency of the sound wave, I:

1. Used a tuning fork which emits a known frequency.

2. Alternatively, I could measure the time taken for a specific number of cycles using a stopwatch and calculated the frequency using the formula:

   $f = \frac{n}{t}$

   where f is frequency, n is the number of cycles, and t is the time taken.

The wavelength was measured by:

1. Observing the resonance in a tube where the sound wave travels.

2. Measuring the length of the tube that supported the standing wave.

3. The wavelength is then calculated using:

   $\lambda = \frac{2 L}{n}$

   where L is the length of the tube, and n is the harmonic number (often the first harmonic).

To calculate the speed of the sound wave, I used:

1. The formula for wave speed:

   $v = f \times \lambda$

   where v is wave speed, f is frequency, and λ is wavelength.

2. Substituting the measured frequency and wavelength into this formula gives the speed of sound in air.

Repeating the experiment is important for:

1. Greater Accuracy: To ensure the results are reliable and not due to random error.
2. Improved Consistency: To collect a range of data points that can be averaged for a more precise value of the speed of sound.