15 whistles in 1 hour

These small whistles are originally designed for a school project. 

The idea was to have a functional 3D-model that can print in the time of one lesson (typically 90min in germany) to excite kids about 3D-printing. Ideally this is performed with a small class of ≤15 pupils so everyone can have their own whistle at the end of the lesson. While the printer is printing you can teach a little about how 3D-printing works, what is the process of the idea to the finished product, what a slicer does etc. 

If you have a bigger class of around 30 pupils you might want to add another lesson where you try to design the whistle together with them referring to the things you taught in the first one (of course while printing another batch of whistles for the other 15 kids). Here you might be able to get quite into the details of 3d-printing-optimized design and fundamental designing tools. 

The whistles are quite small but super annoyingly loud and easy to hide so maybe warn your colleages the day you plan on doing this. 

The Model itself is quite simple and consists of just a circle and a rectangular. It is specifically designed to work perfectly with 0.3mm layerheight (wall thickness and bottom as well as top layers - could be quite a topic for the lesson too). At the top I implemented a little chamfer in the inside so the top layer has a base for the bridging.