{"id":52468,"date":"2025-09-17T04:48:23","date_gmt":"2025-09-16T19:48:23","guid":{"rendered":"https:\/\/phys-edu.net\/wp\/?p=52468"},"modified":"2025-10-13T05:36:43","modified_gmt":"2025-10-12T20:36:43","slug":"i-built-a-volcano-and-it-was-explosively-fun-full-experiment-recipe-revealed-volcano-model-with-plaster-baking-soda","status":"publish","type":"post","link":"https:\/\/phys-edu.net\/wp\/?p=52468&lang=en","title":{"rendered":"We Built a Volcano\u2014and It Was Explosively Fun! The Ultimate Experiment Recipe Using Plaster and Baking Soda!"},"content":{"rendered":"

I’m Ken Kuwako, a science trainer. Every day is an experiment.<\/strong><\/span><\/p>\n

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In a science class, the most fun part is always getting your hands dirty and “giving it a try.”<\/span> There’s nothing more rewarding for us teachers than seeing the bright, sparkling eyes of our students and hearing them shout, “I get it!” Recently, I was teaching a class on volcanoes with H-sensei, a student teacher, and the volcano eruption experiment we did really sparked their curiosity.<\/span><\/p>\n

“How does the viscosity of magma relate to the shape of a volcano?”<\/p>\n

The real joy of science isn’t just memorizing facts from a textbook; it’s about “seeing, touching, and experiencing” it for yourself. So, we decided to build a volcano eruption model using common household materials. This experiment looks simple, but it’s surprisingly profound.<\/p>\n

We used just four ingredients: plaster of Paris, baking soda, laundry starch, and water. By slightly changing the “mixing ratio” of these four simple materials, we could make the magma behave and flow completely differently. It was like we were simulating real volcanic activity.<\/p>\n

The most exciting part is the chemical reaction that occurs when you combine plaster (CaSO4), baking soda (NaHCO3), and water. As you might already know, it generates carbon dioxide (CO2)! The volume of our mixture would gently expand as the gas was created, just like a real volcano slowly swells before an eruption. That moment of realizing how a simple chemical reaction can lead to a grand natural phenomenon is the true essence of science education.<\/p>\n

H-sensei and I repeated the experiment over and over, changing the ratios until we found the perfect “recipe.” It took a lot of time, but the feeling of accomplishment when we finally got it right was incredible. It was a great reminder of what scientific inquiry is all about. In this report, I’ll share the details of the experiment, including the ratios we discovered through trial and error, and show you what the successful eruptions looked like!<\/p>\n

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Materials<\/h2>\n

\u30fbPlastic containers
\n\u30fbPlaster of Paris, 10g x 2 \u2190 Put into a resealable bag
\n\u30fbBaking soda, 5g x 2 \u2190 Put into an evaporating dish
\n\u30fbLaundry starch (PVA)
\n\u30fbWater
\n\u30fbSpatula
\n\u30fbGlass stirring rod
\n\u30fbTray<\/p>\n

For the plastic containers, we used these from Daiso. The size is important, so if you’re trying this at home, be sure to get the same ones.<\/p>\n

Daiso 70ml 4-pack, Round Mini Containers<\/a><\/p>\n

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Use a drill to make a hole in the bottom of the plastic container and cover it with cloth tape beforehand.<\/p>\n

Now for the all-important mixing ratios:<\/p>\n

Low-viscosity magma type: 1ml PVA laundry starch + 30ml water
\nHigh-viscosity magma type: 10ml PVA laundry starch + 15ml water<\/p>\n

Pour these mixtures into separate containers beforehand.<\/p>\n

\u3010Experiment Procedure\u3011<\/p>\n

\u2460 Thoroughly mix the PVA laundry starch and water in the plastic container with a glass rod.
\n\u2461 Add the 10g of plaster (from the resealable bag) to the plastic container.
\n\u2462 Mix the plaster, PVA laundry starch, and water well with the glass rod until they are fully combined.
\n\u2463 Once mixed, add the 5g of baking soda and quickly mix the entire solution with the glass rod.<\/p>\n

The key here is to mix everything quickly and close the lid immediately.<\/p>\n

If the baking soda is clumpy, crush it with a spatula beforehand!<\/p>\n

\u2464 Close the plastic container’s lid, flip it upside down onto the tray, and immediately peel off the tape.
\n\u2465 Observe the spread of the solution (lava) from directly above the model.<\/p>\n

Experimenters must wear polyethylene gloves! Everyone must also wear a lab coat and safety goggles!<\/p>\n

We conducted this experiment for both the high-viscosity and low-viscosity solutions.<\/p>\n

Here’s how it looked in action:<\/p>\n