How To Build The Best Balloon-Powered Sponge Boat!

Let’s set sail for a STEAM-y summer starting with a Balloon Powered Sponge Boat! This is a simple summer craft (that you probably have all the supplies for!) that is fun for all ages. Once the boats are ready to sail you can launch them in just a few inches of water. So, a pool is great for a sponge boat, but so are bathtubs, wading pools, and deeper splash pads.

Ready to craft? Let’s get constructing!

MATERIALS:

Scissors
Permanent Marker
Ruler (optional)
Balloon & a smaller balloon (optional)
Flexible Straw
Rubber Band
Sponge (at least ¾ thick)
pencil (optional)

BALLOON-POWERED SPONGE BOAT DIRECTIONS:

1. First, measure the short side of the sponge and mark the center.

2. On the same end of the sponge, measure down the long sides the same distance as it was to the center in #1. Mark it on each side. Connect the side mark to the center mark, on each side, to create 45-degree angles for the bow of the boat.

3. Cut along those lines to make the pointed bow. Discard the pieces.

4. Next, from the bow point, find the center of your sponge by measuring halfway down the length of the boat. Mark just behind that.

5. Adults, use the scissors to make a vertical slit/ hole. This will be pretty easy in a dry sponge.

6. Put the end of the balloon through the hole.

Tips: Before you position the balloon stretch it and inflate it to make it easier to blow up once assembled.

Also, I used the tip of a dull pencil to make the hole a little bigger. Then catch the rolled lip of the balloon to squeeze it through the hole. The tighter you can keep the hole the more secure everything will stay together.