Here’s a fun way to propel a boat forward, thanks to the fizzy reaction between an acid and a base. It’s an easy and quick STEM lesson with an automatic payoff.

The set-up requires a little grown-up work. First, cut a small hole in the bottom of an empty water bottle. Cut a straw in half and insert into the hole, then close up any open gaps with hot glue.

To make the “fuel” for the boat, pour a little vinegar into the bottle. Make sure the straw is on the top of the bottle as your pour, so none spills out. Now spoon in a little baking soda, but don’t let the two substances mix yet! Screw on the bottle cap, then set your “boat” down in a basin or bathtub filled with water. The acid and base mix, and the boat zooms forward.

Note: Make sure the straw is in the water for this part, or the experiment won’t work as intended. We learned this after round one!

Next time, we would do this experiment with a larger water bottle (making it easier to keep the baking soda and vinegar separate until the right moment), and we’d also do it in the tub so the boats have more room to zoom. But Travis still loved watching the little motion we achieved!