A Geologic Lesson for the Little Ones

Sharing one’s knowledge with others is one of the greatest gifts that anyone can give. Being a young, aspiring teacher, I especially advocate this idea. The whole reason why my group and I are on this incredible journey in Santorini is to come back to the United States and share our geologic knowledge of what we have all learned and discovered about the Minoan eruption of Santorini that occurred thousands of years ago.

Some of the knowledge that I have gained from this experience is that the Minoan eruption, an ultra-Plinian eruption that dates back to 1613 (plus or minus 13) B.C., occurred in five separate phases (1). This volcanic eruption was one of the most significant eruptions of all time because it buried the creations of an extremely advanced civilization that once resided in Akroteri and completely changed the landscape of Santorini. The Volcanic Explosivity Index (VEI), which measures the strength of volcanic eruptions, is still debated to this day, but the most recent number that has been provided was a 7.1 strength eruption on a scale of 0-8, with 8 being the most explosive (1).

A schematic of what Santorini looked like before and after the Minoan eruption.
A schematic of what Santorini looked like before and after the Minoan eruption.

The zero phase of the Minoan eruption was a thin “warning” layer of fine ash. This phase of the eruption, along with volcanic tremors or earthquakes,warned the inhabitants of Santorini that the volcano was on the brink of erupting, which caused them to flee the island.
The first, official phase of the eruption was the beginning of a Plinian eruption. There was a steady Plinian eruption column full of pumice, which mainly blew that material to the south and east due to the direction of the wind. Eventually, that pumice began to fall from the Plinian column.

A piece of pumice from the first phase of the Minoan eruption.
A piece of pumice from the first phase of the Minoan eruption.

In the second phase, the eruption column had fallen, which facilitated pyroclastic base surges. Base surges are when pyroclastic material spreads in such a way that it rolls rapidly and causes significant changes in bedding patterns, as opposed to regular pyroclastic flows that move linearly and create straight layers in a bed. Additionally, the vent of the volcano began to widen, and widened so much to a point where cool sea water entered the vent of the hot volcano, which caused the volcano to create rapid, violent explosions. These water-to-magma interactions are called phreatomagamtic eruptions. The base surges created layers of graded pumice, and the phreatomagamtic reactions caused many large lithic fragments or pieces of the volcano that were ripped and thrown from the vent.
Throughout the third phase, the vent of the volcano continued to widen, causing more pieces to break off (1). Sea water was also still proceeding into the vent, even more so since the vent was constantly widening. There was also a second eruption column created in this phase, but instead of the column being directed vertically into the air, “turbulent clouds of ash were directed laterally outward at low angles” (1). Due to the circumstance of the direction the eruption column, this caused the cool, wet pyroclastic flows to “boil over” the caldera rim.

The fourth and final phase of this catastrophic eruption is still widely debated. Most recent interpretations say that a tuff ring was created by the build up of tephra and lithic fragments from the previous phase’s lateral pyroclastic flow, which prevented the ocean water from continuing to enter the vent, thus creating a layer of hot, dry pyroclastic flow (2). Eventually, this tuff ring ultimately got destroyed from the destructiveness of the volcano, and ocean water once again began to enter the vent. The re-entering of sea water created the second half of the fourth phase, which contained a cool, wet pyroclastic flow.
While the science and geology of this disastrous Minoan eruption seems complex, there is a way that this subject can be taught to small children; namely, my forte, kindergarteners. Provided below is a full lesson plan that teachers can utilize based on the five phases of the Minoan eruption. It will educate kindergarteners about one of the most significant volcanic eruptions of all time, and how to identify volcanic eruption layers in a very basic way.

A schematic of the Minoan eruption layers. Taken at the Museum of Ancient Akroteri.
A schematic of the Minoan eruption layers. Taken at the Museum of Ancient Akroteri.

Lesson Title: The Five Phases of the Ancient Minoan Eruption in a Craft

Lesson Goals: To motivate students to use their individual creativity for crafts. To have students identify volcanic material in a basic manner. To have students identify and comprehend volcanic processes in a basic manner. To have students identify the five Minoan eruption phases in a basic manner. To have students understand the geology and morphology of the Ancient Minoan caldera.

Rationale: I will be teaching this lesson because the Minoan eruption was one of the most important volcanic eruptions of all time, and American students should have a diverse knowledge of world events. Along with gaining diverse knowledge, the will also learn how to use geological observations in order to understand the basic process and layers of the Minoan eruption.

State Standards (AZ):
Concept 1: Observations, Questions, and Hypotheses
PO 2. Ask questions based on experiences with objects, organisms, and events in the environment.
Concept 2: Scientific Testing (Investigating and Modeling)
PO 2. Participate in guided investigations in life, physical, and Earth and space sciences.
Concept 3: Analysis and Conclusions
PO 1. Organize (e.g., compare, classify, and sequence) objects, organisms, and events according to various characteristics.
PO 2. Compare objects according to their measurable characteristics (e.g., longer/shorter, lighter/heavier).
Concept 4: Communication
PO 1. Communicate observations with pictographs, pictures, models, and/or words.

Prior Knowledge: Students are required to know, or at least have a basic idea of, the history of the Minoan eruption. For example, where it happened, when it happened, what sort of effect it had locally and globally, and the like. They must also know what a caldera volcano is, and what it looks like.

Clear plastic Dixie cups that have the phase thicknesses marked on them. This will give the students an idea of how thick the layers are.
Red (magma), brown (volcanic rock), and blue (water) Play-Doh or putty (one of each color for each student).
Fine sand (for all phases).
Extra small packing peanuts, or finely cut up sponge (for the first phase).
Gravel (for the second phase).
Standard-sized rocks (for the third and fourth phase).
Side Note: Have each “phase material” be separated in plastic snack baggies.

Distribute one plastic cup, one container each of red, brown, and blue Play-Doh, and one bag of each “phase material” to each student.
Have the students build the morphology of the Santorini volcano prior to the eruption with brown Play-Doh, and have “water” surrounding it in their plastic cup. Be sure to check around the room and see if they have their volcanoes built correctly.
For the zero phase of the eruption, explain very simply the process of that phase, and how it lead the Ancient Minoans to flee from the island. After explanation, have students add a very thin layer of fine sand as ash.
Explain the process of the first phase in simple terms. After explanation, have the students add a thick layer of a mixture of packing peanuts or cut up sponge and fine sand as pumice and ash.
Explain the process of the second phase of the eruption and how it is composed of two layers in simple terms. Also, be sure to define what a base surge is to the students, and discuss what the difference is between a base surge pyroclastic flow and a regular pyroclastic flow. Confirm the students’ understanding of the second phase. After explanation, have the students stretch their caldera rim slightly, and add “water” into their caldera, and tear off small pieces of their caldera rim. Finally, have them add a layer of a mixture of fine sand, gravel, and rocks to represent fine ash and multiple-graded lithic fragments.
Explain the process of the third phase of the eruption in simple terms. After explanation, have the students widen their caldera rim a little more, and rip off a few more pieces of their rims. Also, have them add more water into the vent of their calderas. Finally, have them add an additional layer of the sand-gravel-rock mixture into their cups. If possible, have them “roll” the mixture from the rim of their caldera down, as to represent the spilling over of volcanic material.
Explain the process of the fourth phase and how it is similarly comprised of two layers, like the second phase. Focus on describing what a tuff ring is, and how it was formed around the caldera due to the materials from the third phase. After explanation, for the first part of the phase, have the students build a ring around their caldera, remove the “water” from the inside of their caldera, and add a layer of a mixture of fine sand and gravel to represent ash and lithic fragments.
For the second part of the fourth phase, explain that the tuff ring was destroyed, and ocean water began entering the vent once again. Finally, after explanation, have the students remove their tuff rings and add “water” to the inside of their caldera once again, and add a layer of a mixture of fine sand and rocks to represent ash and large lithic fragments.

Homework/Assessment: As an informal assessment, have the students get into groups of two and have them discuss each phase of the Minoan eruption and what they are made of. Cue them as to when they can move on to explain the next phase. To confirm that their explanations are correct, circle around the room and listen to their conversations. Correct students when necessary. As homework, there will be a handout of a worksheet. On the worksheet, there will be a silhouette image of the five Minoan phases in their layers, but the inside of the layers will be blank. Students will be required to fill in each blank layer with drawings and specific symbols that represent what materials were in each layer. For example, ash will be represented by dots, pumice will be represented by “~” signs, and lithic fragments will be represented with black squares; the size of the squares represents the grading of how big or large the lithic fragments are, so be sure to make a point of that.
Troubleshooting: If you think the students will have a hard time with mixing their layers that are required to be mixed, have them mixed beforehand. Also, if you think that this lesson will be too messy, you can have plates or paper towels laid out on the desks as to prevent an even bigger mess.

For questions, comments, or any other concerns about this lesson plan, you can email me at cds284@nau.edu.

(1) Friedrich, W.L., 2009. Santorini: Volcano, Natural History, and Mythology, Denmark Aarhus University Press

(2) Druitt, T.H. 2014, New insights into the initiation and venting of the Bronze-Age eruption of Santorini (Greece), from component analysis. Bull Volcanology, 76:794


4 thoughts on “A Geologic Lesson for the Little Ones”

  1. Great description of all the phases Carly! So good that I referred to it in my blog. The lesson plan was very solid, and I would not be surprised if it was eventually put to use. You have some great ideas!

  2. Wow Carly, I really like the organization and simplicity of your lesson plan. I can tell that younger grade school children would really get a solid grasp on the eruption processes, while having fun at the same time. I wish i would have had more interactive lessons like this during the beginning of my education..
    After reading this and spending two weeks with you, I can already tell that you’re going to be an awesome Kindergarden teacher. Keep it up!

  3. Carly – I have many teacher friends who are constantly looking for new and exciting ways to incorporate science into the classroom – especially when it comes to volcanic eruptions as the little guys love explosions! I am happy to see that you found a topic you are passionate about and hope you come away from this class with many more ideas for incorporating earth science lessons into young classrooms. Spread the word! Our children need it!

  4. Wow, Carly. This is an excellent post for teachers who are interested in teaching a specific science lesson to kids. You didn’t just provide the lesson, but you also provided us with the context/why this is important. It makes sure that teachers know what to teach and why to teach this lesson. It’s very clear too that you are familiar with lesson plan requirements. Including the state standards will help teachers see that they can easily incorporate the lesson into their curriculum. Great job!

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