Make: Technology on Your Time Volume 26

TOY INVENTOR’S NOTEBOOK

Make a Diving SpudMarine!

INVENTED AND DRAWN BY Bob Knetzger

HERE’S A FUN AND FAST WAY TO CREATE a homemade version of the classic cereal premium toy, the baking powder-powered diving submarine. Instead of plastic, we’ll make one out of a potato. It works well — and when you’re done, you can eat it!

First, cut a potato into a ¾"–1" diameter cylinder, about 3" long. Use a piece of ¼" brass tubing as a plug cutter. Press the tube all the way into the potato to make 3 through-holes evenly spaced along its length. This will ...