The difference in air pressure made the rocket behave abnormally, and probably contributed to the crash.

ECONOMIST: Hypersonic aviation

This tracks the difference in air pressure between Iceland and the Azores and, during the winter months, determines the strength of the winds, temperatures and rainfall in the St Kilda archipelago.

ECONOMIST: Evolution and climate change

"The difference in the game was the level of pressure they put on us in the second half and certainly the shots they made, " Butler coach Brad Stevens said.

NPR: Blue And Marquette Show Butler The Door, 74-72

Marquee investments in companies like Facebook make a big difference when firms are out building their war chests, putting pressure on them to get in on hot deals.

WSJ: In Silicon Valley, Founders Fight for Control

Even the reluctance of Lebanon and Iraq to apply full sanctions will be unlikely to make a big difference in Syria's fortunes, especially as international pressure continues to mount.

CNN: Syrian isolation marks regime's nadir

"In our studies, ball pressure made a big difference, " Dr. Plant said.

WSJ: Soccer 'Header' Impact Likened to Hard Punch