Longitudinal and Transverse Wave Motion
https://www.acs.psu.edu/drussell/Demos/waves/wavemotion.html
Earthquake Waves
http://www.geo.mtu.edu/UPSeis/waves.html
Sound Waves
https://js082.k12.sd.us/my_classes/Physical_Science/Sound/soundpage.htm
Cool Picture!
http://antwrp.gsfc.nasa.gov/apod/ap010221.html