Distance to Sound app for iPhone and iPad

DTS lets you estimate the distance between an event that you can see (a firework exploding, a bolt of lightning flashing across the sky or a rocket taking off) and your current location. It uses the time it takes for the sound created by the event, adjusted for the temperature of the surrounding air (a setting which you can easily adjust), to estimate the distance between you and the event.

Using Distance to Sound is about as easy as it gets.

- Wait for a flash of light created by the event, then quickly press the center button

- Wait for the sound of the event to reach you.

- Quickly press the button again.