HC-SR04/ ultrasound speed

Hi I,m a student and I,m new to arduino world so I need help. I have bought the ultrasonic sensor yesterday and i wanted to calculating the speed of the sound wave, I became 342.072 as a result with deltaC=+_ 33,87 m/s is this a normal result I mean the deviation ist not to big? I,ll be very happy if someone could help me. :(

If you show the program you're using to calculate the speed of sound then perhaps we can help. If we don't know what you've done we can't really say if it's right or wrong.

The speed of sound (or ultrasound) in air is approximately 343 m/s so you're close. The deviation seems too high but that will depend on how you're calculating it.


Thank you for replying.
I have used a board with 10cm to the front side of the ultrasonic sensor and I recorded 50 values of the time of ultrasonic it needed to the board and the way back. Then I have calculated the mean value. To calculate the ultrasonic I used the equation C=2s/t as to seen in the photo bellow
Distance deviation = 10mm