Wavelength: lambda: the distance between any point on a wave and the corresponding point on the next crest (trough) of the wave; distance the wave travels during one cycle; expressed in meters, nanometers, micrometers, picometers m) or angstroms
PHD Comics: Gravitational Waves Explained Simple explanation but really interesting for further understanding on gravitational waves. "That's one small step for man, one giant leap for mankind" Neil Armstrong quote Mehr
Surface Tension Water Experiment - Water Drops On A Penny
Radio spectrum refers to the part of the electromagnetic spectrum corresponding to radio frequencies – that is, frequencies lower than around 300 GHz (or, equivalently, wavelengths longer than about 1 mm).