Sharpen your science skills with this 3-pack of engineering projects.

1. Headphones
Build the headphone headband, rig up the speaker drivers, and experiment with stereo sound. Explore how speakers and other electroacoustic transducers turn electricity into sound, then learn about the historical technologies that made modern headsets possible.

2. Pencil Sharpener
Sharpen some pencils — and your engineering knowhow — with a pencil sharpener you built yourself!

3. Trashketball
Put the "fun" in functional by engineering a linkage-powered trashketball game.

All 3 projects delivered together.