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[dropcap]B[/dropcap]aking soda and vinegar volcanoes may be the quintessential science experiment for kids ages 4- 12 – and for good reason! It's absolutely fun and can be done with children of various ages at the same time, so it's a great option on a rainy day when kids need something constructive to do.
My favorite way to build the volcano is with paper mache, but that often takes too long and it can get overly messy with younger children. Making your own modeling clay is an easier and quicker way to build the mountain and is more easily adaptable to different shaped jars and tubes that hold the “lava.”
Here's our homemade version:
Modeling Compound for the Volcano
- 6 cups all-purpose flour
- 2 cups regular table salt (don't use your expensive mineral-rich salt for this project!)
- 4 tablespoons cooking oil (a great way to use up the lesser-desirable oils in your kitchen, such as safflower, corn, or canola)
- 2 cups warm water
Mix until it's smooth and firm, adding more water if absolutely necessary. This makes a very firm but pliable modeling compound.
Baking Soda and Vinegar Lava
- Warm water
- A few drops of dish detergent
- A few drops of food coloring
- Baking soda
- White vinegar
- A small pitcher
Find a bottle or container that's about 3-4 inches high and 1-2 inches in diameter. (One of our leftover small Evenflo or Gerber baby bottles worked like a charm.) On a rimmed baking sheet or other area that can get messy, sculpt the volcano around the bottle.
In the small pitcher, stir a couple of tablespoons of baking soda into 1/2 cup of water, then add a few drops of food coloring and a very small squirt of dishwashing detergent. (The detergent will help give the carbon dioxide bubbles more surface tension, thus creating a more bubbly “explosion.”)
To make the volcano erupt, pour some of the baking soda solution into the bottle, filling it about half-way. Pour in several tablespoons of vinegar all at once and watch the mixture bubble over.
Good Discovery Questions for Kids
1. Does pouring the vinegar at various speeds affect how fast the volcano erupts?
2. Does the shape of the volcano affect the direction the eruption travels? If the shape of the cone is changed, does the lava flow change?
3. What can be added to the “lava” to slow it down and make it more like real lava? Can you think of any clues according to what is found in real lava?
4. What combination of food coloring colors creates the most realistic lava?