Tone generator
Play a sound of any frequency. Useful for physics experiments on sound, testing speakers and headphones, and tuning instruments.
Start with the volume low. High-pitched tones can be uncomfortable.
About frequency and sound
Frequency is how many times a sound wave vibrates each second, measured in hertz (Hz). A higher frequency sounds higher. People hear roughly 20 Hz to 20,000 Hz, and the top limit drops with age. The A above middle C is 440 Hz, and each octave up doubles the frequency.
Using it for a school physics experiment?
Try the resonance tube or sonometer experiment: play a known frequency and find the length where the sound is loudest. The speed of sound is about 343 m/s at 20 °C, so wavelength = 343 ÷ frequency.
Is it safe?
Keep the volume low, especially with headphones, and stop if a sound is uncomfortable. Very low tones may not play on phone speakers.