If you are provided with a powerful cracker, a stop watch, a measuring tape and a friend to help you, explain how can you measure the approximate speed of sound.

  Dear student,
The procedure is as follows:
1.Choose two spots.Ask your friend to stand at one of the spot with a cracker and take the other sport for yourself at a distance of 100 m from the first spot so that you can see the cracker. Perform the experiment at dusk so that you can observe the cracking easily.
2.The meter tape should be used to measure the distance.
3.Now give signal to friend to burn the cracker.
4.Once you see the flash of explosion of cracker, start the stop watch.
5. When you hear the sound of explosion, stop the stop watch.
6.Now you have time taken by sound to cover 100m
7.So, velocity of sound will be simply distance divided by time.
8. Perform the experiment few more times to get better results.

Approximation:
As speed of light is greater than speed of sound, so it is approximated that the light instantly reaches to us when the cracker explodes.
The winds affects the speed of sound but here the speed of wind is neglected.
Regards