Mystery Image Contest: September 9-23, 2013


Lava is the molten (or melted) rock that comes out of a volcano when it erupts. While it is hot, lava can flow over land and move great distances. A "river" of lava is called a flow, and it continues moving as smaller "toes" from the edges break out and move forward. The image above is of a lava toe oozing onto an asphalt road — because the lava is so high in temperature, it has actually set fire to the road! Over time, lava cools and returns to its solid state, in which it looks like rock. There are many different kinds of lava, classified according to their chemical makeup, appearance, or form they take when cooled. The lava above is classified as "pāhoehoe," which means that it has a smooth or billowy crust of cooled lava on the outside, with hot fluid lava underneath. The name pāhoehoe is borrowed from the Hawaiian language, where it means "smooth, unbroken lava." The lava in the image above can therefore be described as a pāhoehoe toe. This pāhoehoe toe actually came from an eruption of Kīlauea, the most active volcano on the island of Hawai'i in the Hawaiian Islands. Because so much volcanic activity takes place on the Hawaiian Islands, several scientific terms in the study of volcanoes are borrowed from the Hawaiian language. Besides pāhoehoe, these include "ʻaʻā," or molten lava with broken rocks embedded in it; and "kīpuka," or an elevated hill or ridge downhill from a volcano that becomes isolated when lava flows around it.


This picture is of lava, specifically a pahoehoe toe.

Photo Credit

U.S. Geological Survey (http://gallery.usgs.gov/photos/08_20_2010_kPGr3VU221_08_20_2010_1)

Winning Entry

Our classroom and individual winners are:
Mrs. Aguilar's Class — Water's Edge, Saxapahaw, NC
JB Carroll — St. Louis, MO

For Educators

Teaching Support

As volcanoes are fascinating to most people, including students, this image would be a good jumping-off point to a number of topics. Discussion of lava flows could segue into a lesson about volcanic activity and its potential to change landscapes, or about its place in historical and present consciousness (with discussion of volcanic eruptions from Mount Vesuvius in 79 CE, to Mount St. Helens in 1980). Volcanic activity also has close ties to geology and could inspire learning about the types of rock involved in volcanoes. Discussion of lava and how it exists visibly in both liquid and solid states could be a good example of states of matter. Or, more generally, use this image as an example of a phenomenon of earth science and an introduction to a related lesson.

Related Resources

Erupting Volcanoes!
Model Volcanoes
3-5 | LESSON
Shape It Up
3-5 | LESSON
A Matter of State
6-8 | LESSON
Earth Movers
9-12 | LESSON

Science NetLinks Mystery Image Contest Rules and Regulations

What Is the

Mystery Image Contest?

The Mystery Image Contest offers the chance to identify a science-related object based on a close-up picture of it.