Perform your own volcanic eruptions on the tabletop, in the bath or even inside a glass! It's an awesome science gadget that will captivate the imagination!How does it work? The baking soda is a base while the vinegar is an acid. When they react together, the form water and carbon dioxide, which creates all the fizzing as it escapes the solution. Did you know that volcanoes are openings in the Earth's surface, and are usually located where tectonic plates meet. Hot liquid rock under the Earth's surface is known as magma, it is called lava after it comes out of the volcano.