What is the “sound barrier,” when was it broken, and why was it such a big deal?
Groliers: Bingo! Multi-level search produced explanation of sound barrier, and mention of Chuck Yeager’s historical event. No photos or videos of the Bell X-1, but nice photo and video of the X-15. Comptons: Partial answer. Idea search yielded answer that Chuck Yeager broke the barrier in 1947. No photos or videos. Microsoft: Strike-out. Best effort by our reviewers was to find an explanation of the speed of sound. Nothing on the sound barrier, nor Chuck Yeager’s efforts. • When and where did Martin Luther King give his “I have a Dream” speech, why did he give it, and what was the complete text of the speech? Groliers: Strong partial answer. Search produced article, 30 second audio track of speech, and 70 second video clip of the August 23, 1963 civil rights march. Full text of speech, however, was not provided. Comptons: Partial answer. Search produced 28 second audio track from speech, plus three still photos. Sound track was more clear than Comptons. Microsoft: Partial answer. Searc
