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Baking soda and vinegar are two of the most versatile substances in the world of at-home science. We’ve used them multiple times here on Saturday Science and today we’re going to explore what happens when you introduce some ice into the mix. If you’ve made a baking soda and vinegar volcano before, you’ll have some idea of what to expect, but it’s going to be a little bit different this time…
Materials
- Water
- Baking soda
- Vinegar
- Cups or small bowls
- Plastic wrap
- Golf balls
- A freezer
- Food coloring (optional)
- Eye droppers (optional, but nice)
Process
- The first step is to mix up your volcano material. Mix some baking soda up into some water. The exact amounts don’t matter too much, but make sure it isn’t so much that the baking soda is settling on the bottom of your cup. If you want to use food coloring to color your volcanoes, mix it in now.
- Next, you need to make your volcano molds. For each mold, put a golf ball into the bottom of one of your cups or small bowls. Make sure it’s in the middle.
- Tear a piece of plastic wrap and push it down into the cup/bowl on top of your golf ball. Work it around the ball so it’s kind of an upside down, empty volcano shape with the golf ball being the caldera (the crater at the top of the volcano). Fold the extra plastic wrap down over the outside of the cup/bowl. Repeat this as many times as you want to make multiple volcanoes.
- Pour your volcano mixture into your cups until they’re almost full.
- Pop your volcanoes into the freezer. Give them time to freeze.
- Once they’re frozen, pull them out and let them thaw for a few minutes, then lift the plastic wrap out of the cup and carefully remove it from the volcanoes. Turn them upside down and, bam, you’ve got a frozen volcano!
- Now we add the vinegar. This is going to be a bit different from regular vinegar and baking soda, so make some observations while you’re adding it. This is where eyedroppers come in handy, but if you don’t have one, just trickle it into the volcano’s caldera with another cup.
Summary
The science behind baking soda and vinegar is pretty simple. Mixing them causes what’s called a chemical reaction. This is when two substances meet and start swapping around the molecules (the tiny little pieces) that they’re made of. Something different is created when a chemical reaction is finished. In this case, you start with baking soda and vinegar and end up with sodium acetate and carbon dioxide gas, which bubbles out of the liquid and causes the fizzing.
This is a bit different than your normal baking soda and vinegar reaction, though. If you paid close attention you might have noticed that it went a bit more slowly than simple adding baking soda to room temperature liquid vinegar. This is for a couple of reasons.
First, you mixed your baking soda into water, which diluted it. If you somehow had a volcano made of pure baking soda, it would have reacted way better. Mixing some into the water means that there’s less baking soda around, so less to react with the vinegar.
Second, this time it was really cold when the reaction was happening. Chemical reactions slow down when you make them colder. Heat provides the energy for the molecules to do their swapping dance, and the less heat there is, the slower they move around. They’ll get there eventually, but it might take a while.
What’s really neat about making an ice volcano is that you’re sort of modeling something that occurs naturally in the solar system. All of the volcanoes we have on Earth spew hot lava onto the surface, but other solar system bodies have what are called cryovolcanoes, volcanoes that spew cryomagma, a mixture of water and chemicals like methane or ammonia (“cryo” means “cold”). Cryovolcanoes exist on ice moons of other planets, like Triton, one of the moons of Neptune, and Enceladus, one of the moons of Saturn. The cryovolcanoes on Enceladus’s south pole blast cryomagma 1000s of miles into space!
