Bullroar

If your a "child of the 80s" like me you probably remember the movie Crocidile Dundee, and it's Sequel. In the second movie Mic Dundee goes up on the side of a mountain and makes a "telephone call" to all the locals. He uses a Bullroar which is something the aborigines have been using for hundreds of years. It produces a thrumming noise kinda like the prop of a cessna airplane.
I tried carving one of these a long time ago and while it did sort of work it wasn't as nice as I had hoped. So A couple weeks ago i found my original carved one and decided to model it and print a new one. It does work (although not a loud as in the movie). A teacher could easily use this as an experiment as there is a lot of science and math that could be involved. Firt, how many middle sections do you need to print, secondly how much rope do you need to get the maximum sound etc.

a word of warning you might want to wear a leather glove when you try it the first time. you will rub a blister on your rope hand if you don't.

1. Print 1 top, 1 bottom and as many middles as you want.
2. Super glue them together.
3. tie a sturdy chord or rope to the top. You will need at least 2-3 feet of rope. make sure your chord is strong stuff. Even though this thing is light as a feather it will still have some pretty good force pulling on it.
4. take out side to a nice open area. Swing the bullroar in FAST circles at your side. The speed you swing with and the ocassional movement of the rope in your hand will eventually cause it to start to thrum.
5. Start up a BBQ because you just invited all your mates over. :c)