Buzz
Often likened to the molten cheese on a pizza devoured too hastily, lava is celebrated as one of Earth's hottest elements. But exactly how intense is lava's heat? How swiftly could it burn you and obliterate everything in its way?
You might already be aware that lava is essentially molten rock that erupts or flows out of volcanoes due to the extreme heat deep within the Earth. As the rocks melt, they rise toward the surface. (Lava is called magma until it breaks through the surface.) The amount of heat required to melt rock is truly immense. Cooler lava—relatively speaking—can reach temperatures around
Why is there such a wide range of temperatures? Different environments create distinct chemical compositions and minerals that can influence temperature. Lava from Hawaii, formed from basalt rock, tends to be hotter, whereas lava from areas like Mt. Saint Helens in the Pacific Northwest can be a few hundred degrees cooler.
Once lava erupts and begins to cool, it eventually solidifies back into rock. Hotter lava flows faster—possibly several feet per minute—then slows down as it cools, sometimes only moving a few feet in an entire day.
Since lava moves slowly, there's little immediate danger. But imagine, in a particularly unfortunate scenario, you end up exposed to lava—perhaps being thrown into a lava pit like a villain in a fantasy story? You’re not likely to sink quickly into it. Lava is three times denser than water and won't just move aside rapidly. However, at those extreme temperatures, you’d burn like a S'more, even if you wouldn't fully melt. It’s more likely that the radiant heat would scorch you before you even reached the lava lake, or you could catch fire upon contact.
Given how intensely hot lava is, you might wonder how scientists can measure its temperature without wrecking their equipment. A meat thermometer won’t cut it, as the mercury would boil and the glass would break. Instead, volcanologists use thermocouples, which are two wires connected to the same electrical source. By measuring the electrical resistance at the tip, they can convert that into a temperature reading. Thermocouples are made from ceramic and stainless steel, both of which have higher melting points than even the hottest lava. But don’t try this with your pizza.
