Gravitational pull is the invisible force that causes massive objects to pull other objects towards them. For instance, when a person jumps up in the air, it is the earthâs gravitational pull... Gravitational pull is the invisible force that causes massive objects to pull other objects towards them.
Audacity is a free, easy-to-use audio editor and recorder for Windows, Mac OS X, and GNU/Linux. You can use Audacity to: 1  Record live audio; 2  Cut, Copy and Paste, Delete, Duplicate, and Split audio files; 3  Change the speed, pitch or volume of a recording; 4  Apply effects to any part of the sound; 5  Align audio segments.
Recordings and corrections provided by Yoonseop Kang. Download all the audio files (Zip format, 1.1MB). If you would like to make any corrections or additions to this page, or if you can provide recordings, please contact me. You can make recordings on you computer, tablet, phone or other device and email them to me. Audacity is a good, free sound recorder and editor.