Science, Maths & Technology
What are waves?
...Open-source, interactive, educational demonstrations provided by Academo. [Online]. Available at: https://academo.org/ demos/ wave-interference-beat-frequency/ (Accessed 19 June 2019). Wave on a string (2017) PhET Interactive Simulations provided by University of Colorado, Boulder. [Online]. Available at: https://phet.colorado.edu/ en/ simulation/ wave-on-a-string...