Lava is molten rock that has been expelled from a volcano and flowed onto the Earth’s surface. Creating “lava” for a science project usually involves two approaches: simulating the explosive eruption or modeling the unique flow characteristics of the liquid rock. Both methods use accessible materials to model complex natural phenomena safely.
Creating Simulated Lava for Projects
A simulation focused on the explosive nature of an eruption uses a straightforward chemical reaction with common household ingredients. Place a plastic bottle inside a model volcano structure. Add a few tablespoons of baking soda (sodium bicarbonate) and a squirt of liquid dish soap for extra foam. Pour in a mixture of vinegar (an acetic acid solution) and red or orange food coloring to trigger the reaction. This acid-base interaction rapidly produces carbon dioxide gas, which builds pressure and forces the foamy liquid out, modeling a volcanic eruption.
To model the physical characteristics of a slow-moving lava flow, a non-Newtonian fluid demonstrates viscosity. A mixture of one part water to about two parts cornstarch creates a substance that acts like a liquid when poured but solidifies when sudden force is applied. Coloring this mixture red or orange allows it to simulate the flow of thick, silica-rich lava when poured slowly down a ramp. This unique behavior illustrates how different types of lava flow at vastly different speeds based on their chemical composition.
The Science Behind Real Lava Generation
Real lava originates deep within the Earth as molten rock, known as magma. The difference between the two terms is location: magma is the molten material stored beneath the surface, often in chambers, while lava is the same material once it reaches the open air. Magma is slightly hotter, with temperatures ranging from 1,300 to 2,400 degrees Fahrenheit, and contains dissolved gases. When magma erupts to become lava, these gases rapidly escape, and the material cools more quickly than it would underground.
Rock melts within the Earth’s interior through two main geological processes. Decompression melting occurs when rock maintains a constant temperature but experiences a reduction in pressure, such as when it rises toward the surface at mid-ocean ridges. The reduction in overlying weight lowers the rock’s melting point, causing it to liquefy. Flux melting occurs at subduction zones, where water and other volatile compounds are introduced into the hot mantle rock. The presence of water acts as a flux, lowering the melting temperature of the surrounding rock and generating magma.
Ensuring Safety and Cleanup
Simulated lava projects use non-toxic, food-grade materials, making them safe for home use, but adult supervision is necessary for young participants. Always wash hands thoroughly after handling the materials and ensure that no part of the mixtures is consumed. The baking soda and vinegar reaction should be performed in a tray or basin to contain the foam and liquid overflow, as the eruption can be vigorous.
Cleanup for both types of simulated lava is straightforward and safe for household plumbing. The cornstarch and water mixture should be mixed with plenty of excess water before being poured down a drain to prevent clogs. The diluted vinegar and baking soda mixture, which is essentially saltwater once the reaction is complete, can be safely rinsed down the sink with running water.