How Does The Types of Lava at Volcanoes Work?

Lava is just hot, melted rock that oozes out of a volcano, and its behavior depends on what is mixed inside it.

Think of lava like two different kinds of syrup on your pancakes.

Basaltic lava is like thin maple syrup. It is hot, runny, and flows fast. You can see your reflection in it. It spreads out like a thin sheet. This happens because the lava is mostly liquid with very few bubbles or rocks trapped inside. It creates smooth, rolling shapes called pahoehoe that look like braided ropes or smooth cushions.

Andesitic or Rhyolitic lava is like thick peanut butter or honey. It is cooler and much stickier. It does not flow easily. Instead, it piles up into steep cones. As it cools and hardens, it breaks into jagged chunks. These broken bits are called aa (pronounced ah-ah). They feel rough and sharp, like crushed gravel or broken glass.

The key difference is viscosity, which is a fancy word for how thick or sticky a liquid is.

The amount of gas trapped in the lava also changes things. More gas means more bubbles. When gas escapes quickly, it can cause the lava to spray or even explode, sending hot ash into the sky. If the lava is thick and sticky, the gas gets stuck, building up pressure until pop!

So, next time you see a volcano, remember: thin lava flows like syrup, while thick lava piles up like dough.