This video is by far one of my favorites. I teach the concepts of piano (quiet) and forte (loud) for a lesson or two. We use it in a song, we learn the definition, we apply. One of my favorite things is teaching kids to say piano quietly and teaching them to say FORTE with their loud or shouting voices. I make them take their hands and say it "like an Italian would! Since Italian is the language of music, you can't say their words in a wimpy way. Get out your Italian hand and say forte FORTE!!" Wow, do they love that.
Then after they understand the terms and how they're used I pull out this video by the artist Bjork. It's so great because it repeats several times and is a very clear example of loud and soft. They love the pageantry of the video and the crazy things coming to life with the forte sections. Sometimes when it changes they'll signal or say that they hear the change, sometimes I just let them watch and ask questions after.
It's a video that they ask about later and want to go back and view over and over. Check it out and enjoy!