Give us a wave, love
Einstein would be very excited but he wouldn't be surprised, his theory of general relativity has been predicting the existence of gravitational waves for 100 years. It's a great opportunity for some NOS discussion in class, how theory needs to be supported by experiment, how the media deals with the science and how developments in technology enable advancement in science. I'm not going to do it now but you could probably go through the whole list of NOS aspects and apply them to this example. The physics of the experiment is quite straightforward, the gravitational wave causes a difference in phase between two lasers which leads to observable interference effects.
If love is a force of nature, does love have a wave too?
For non Brits, in fact probably for non Northern Brits, "give us wave love" is what people in Sheffield say as the Queen passes in her car.
I of course couldn't ignore the challenge of building LIGO in Geogebra. You can vary the % change in space time (much bigger than in reality) and see the signal of the passing gravitational wave. You can also change the distance to the mirrors to show that the size of the signal is dependent on this.