Saturday Science: Baking-Soda Ship
Chances are if you’re into doing science at home you’ve made a volcano out of baking soda and vinegar before. Mix those two substances and you get a bunch of foam shooting out of your pretend volcano like lava! It takes energy to create that foam and bubble it up, and you can use it to do more than just make a volcano. With some creative thinking and a little at-home engineering, you can even use it to power a boat!
- An empty (and clean) 20 oz. bottle
- A straw
- Paper Towel
- Baking soda
- A bunch of water (a full bathtub works well)
- Use your scissors to poke a hole in the bottom of the bottle. Place it near the edge because it needs to be touching the water for the boat to work.
- Cut your straw down to at least half size and poke it through the hole, taping around it on the outside to make an airtight seal.
- Pour some baking soda onto your paper towel and then wrap the paper towel up into a little pouch around it. Make sure it can fit through the neck of the bottle.
- Jam your baking soda pouch into the bottle. Pour some vinegar in on top of it and close the lid as fast and as tight as you can.
- Place the bottle in the water with the straw on the bottom. Watch as it starts to move!
When you mix baking soda and vinegar you’re mixing opposites: vinegar is an acid, and baking soda is a base. Technically speaking, vinegar is acetic acid, and baking soda is sodium bicarbonate. When acids and bases mix they create a chemical reaction. That means that the atoms that they’re made of break apart and recombine themselves into totally new substances. In the case of vinegar and baking soda, one of those substances is carbon dioxide, the gas we breathe out.
If your bottle-boat didn’t have a hole in the bottom, that carbon dioxide would eventually build up so much pressure that the bottle would burst. When you poked your hole and installed your straw, you gave it a way to escape instead of building up. In escaping, it pushes out the straw. Because every action has an equal but opposite reaction, that makes the boat move forward!