Erupting Volcanoes: Science Saturday

We did a few mini-experiments this afternoon to learn more about volcanoes. Unfortunately, I don’t yet have safety goggles for each of the kiddos so I improvised. We may look silly in our snow goggles, but we are safe! 🙂


When you add baking soda to vinegar, a reaction occurs which makes lots of fizz and foam! What actually happens is this: the acetic acid (CH3COOH, and the thing that makes vinegar sour) reacts with sodium bicarbonate (NaHCO3, or baking soda) to form carbonic acid (H2CO3).

It’s a double replacement reaction, and is also a neutralization reaction. Carbonic acid is unstable, and it immediately falls apart into carbon dioxide (CO2) and water (H2O). The bubbles you see from the reaction come from the carbon dioxide escaping the solution that is left. Carbon dioxide is heavier than air, so, it flows almost like water when it overflows the container. The overall balanced reaction is this:

NaHCO3 + CH3COOH —> CH3COONa + H2O + CO2


To do this experiment, you’ll need ammonium dichromate, (NH4)2Cr2O7, an orange crystalline solid at room temperature, which resembles slightly, table sugar. It can be ignited with high heat, such as that from a bunsen burner or a match. As it burns, the dark green solid “fluff” that forms is Cr2O3. The orange, ammonium dichromate, (NH4)2Cr2O7,is decomposed according to the balanced equation below:

(NH4)2Cr2O7(s) —-> Cr2O3(s) + N2(g) + 4H2O(g)

About Eva Varga

Eva is passionate about education. She has extensive experience in both formal and informal settings. She presently homeschools her two young children, teaches professional development courses through the Heritage Institute, and writes a middle level secular science curriculum called Science Logic. In addition to her work in education, she is an athlete, competing in Masters swimming events and marathons. In her spare time she enjoys reading, traveling, learning new languages, and above all spending time with her family. ♥

9 comments on “Erupting Volcanoes: Science Saturday

  1. I think the goggles are cute! 🙂 Also, I’ve never seen a volcano demo where you lit it on fire. Is this a kit? Did you make the volcanos yourself? And, how did you do it differently so you could light it on fire? thanks!

  2. I saved a small ziploc baggie of Ammonium dichromate from when I was teaching. You might be able to get a little from a local jr high or high school. Explain what you plan to do with it… you’ll only need about a teaspoon (depending on the size of your volcano).

  3. Is there someplace besides the school to get the volcano supplies? The boys would real like the second one! I LOVE the expectation in your son’s face and movements!!!

  4. Those were so neat! Thanks for sharing the technical info too! I think snow goggles make great safety glasses! The closest things I could probably come up with are swimming goggles! 🙂

    I also enjoyed your comparison of Classical and Charlotte Mason. I tend to be somewhere between the two myself, though recently I fall more to the CM side.

    Blessings, Eva

Comments are closed.