Alternatively entitled, â€œ1001 Uses for Old Taekwondo Boards, Use #1â€
Our son, like every other child in his Taekwondo class (so I hear), has an under-bed full of these boards. The sheer joy derived from breaking them evidently grants the boards immunity from ever being discarded. This leaves us with a lot of boards which, incidentally, float.
Materials for Propeller Raft:
- Lightweight wood, such as balsa wood, or if you happen to be so lucky,Â board-breaking boards from Martial Arts class.
- Straightedge, such as a ruler. We used the edge of an envelope. â€˜Cuz weâ€™re flexible like that.
- Propeller â€“ ours came from the Party store, and is the type youâ€™d find for 5/$1.00 at the dollar store.
- Rubber bands
- Screw Eye/ Eye bolt
- Pocket knife, exacto knife… something sharp but non-lethal.
Cutting a groove for the propeller in both sides of the wood (we used the straight edge to make, well, a straight edge for the groove):
After Experiment #1 (aka Friction, or, Will the propeller shaftÂ move more smoothly inside the wooden groove, or inside a straw? Straw, totally.), gluing a straw into the wooden groove:
Missing steps include (and not necessarily in this order):
- Insert a screw eye into the end of one of the wood bits. If you look closely, you can see the screw eye underneath the straw in the above picture.
- Loop a rubber band through the screw eye.
- Glue, and when the glue completely fails to hold, rubber band the two bits of wood together such that the straw cannot come loose.
- Insert propeller shaftÂ into straw
Here, Andrew puts the rubber band around the propeller blade:
Twists, and then lets go:
And to the tub, where we try for experiment #2 (or, Which will go faster, the raft with a truck, or without a truck?), and find out that Murphyâ€™s Law ALWAYS applies to experiments (it was very difficult for Boo to wind the propeller and balance the truck at the same time). Lucky kid, I didnâ€™t learn that lesson till grad school.