Final answer:
To control other variables while altering frequency, maintain constant conditions for all factors other than frequency. Use specialized equipment to measure and ensure the stability of conditions.
Step-by-step explanation:
To control all other variables while only changing the frequency, you need to ensure that all other factors that could affect the outcome of your experiment remain constant. For instance, when using a function generator to produce sound, you would adjust only the frequency setting, while keeping the amplitude (loudness) and any other factors, such as the environment or speaker separation, unchanged. An oscilloscope might be used to monitor the changes and verify that only frequency is altered. This allows for the observation of the direct impact of frequency on the system without interference from other varying conditions. Keeping consistent conditions is key for any experiment where you're studying the effect of changing one specific variable like frequency.