The first plane ever to fly faster than the speed of sound was the X-1 in nineteen forty-seven.

VOA: special.2010.07.07

We leave you now with some examples, which we have strung together like beads of sound.

VOA: special.2009.05.18

It would reach hypersonic speeds -- five times the speed of sound.

VOA: special.2010.07.07

It was flying more than five times the speed of sound.

VOA: special.2010.07.07

Snow also is known to influence the movement of sound waves.

VOA: special.2010.01.05

That was more than seven times the speed of sound.

VOA: special.2010.07.07

There are only minutes - sometimes seconds - to react, and the incoming weapons are traveling faster than the speed of sound.

VOA: standard.2010.03.26

"When flying low in combat, speed is life. Now,from the left,Captain Smith and Captain Cox return to show center at 300 feet and nearly the speed of sound,".

VOA: standard.2009.11.15

Only the sound of insects filled the air as I walked through the empty town that summer day so long ago.

VOA: special.2009.07.04

For example, read copies of a group's financial records and be careful of groups with names that sound like well-known charities.

VOA: special.2009.11.02

As a boy,Carl said he knew if it was time to go to school by the sound of a train.

VOA: special.2009.11.01

The wind came again. Finally,the men heard a new sound C the sound of waves breaking and crashing on the shore.

VOA: special.2010.03.06

He never returned. But many nights Sylvie heard the sound of his whistle as she came home with her grandmother's cow.

VOA: special.2010.04.03

On an acoustic guitar, the strings vibrate and the hollow part of the instrument, or the sound box,also vibrates.

VOA: special.2009.09.27