Saturday, August 1, 2009

Volcanic Eruptions!

(Used with written permission)

July 21st was W.S.U.-Rochester E.M.S.P.'s second time visiting with patients, meeting their families, and introducing everyone to volcanic eruptions. Colleen Loy and I started the activity with a book produced by the Smithsonian Institute on volcanoes written by Simon Seymour. From our point of view, the use of books to read to the group is important, but we may need to streamline this part of the activity since we have, for the second time, been given the comment that the kids appeared to becoming restless with the book. Maybe in the future we will simply donate a book and let the patients know it will be available to read when it is convenient. It has been emphasized in the past that enjoyment trumps education so it is our challenge to stuff as much of the latter into the activity!

This introduction to the subject was followed by my personal rock collection of volcanic rock from the Lake Superior Shoreline! Being the geology geek, I find it fascinating that over a billion years ago the North American continent attempted to diverge. This spreading in the middle of the continent lead to the outpouring of magma on and off over a span of millions of years. This evidence can be found up and down the superior shoreline and can read about from the numerous road-side plaques between Duluth and the Canadian border. These lava flows followed by glaciers gave us the Great Lakes!

Vesicular Basalt

These igneous rocks were a great way for the kids to understand and feel what lava feels like when it cools. The various colors represent different minerals found in each rock. The holes in these rocks once housed trapped gas bubbles.

The activity today centered on the fact that there are different types of volcanic eruptions. These eruptions are dependent on several factors that include whether the eruption occurs above a subduction zone or a hot spot. These two areas produce different mixtures (mineral content) of magmas that, because of their crystal structure, allow gases to either easily release from the magma creating a smooth and non-explosive eruption (Hawai’i) or the magma's structure does not allow gas to escape, which in turn builds pressure within the magma. This pressure continues to build until it is suddenly released in a violent and explosive eruption such as Mt. St. Helen in 1980.

The items used in this activity are for a single volcano. Magma ingredients include baking soda, vinegar, red food coloring, and strawberry Quik (for the slower lava simulation). The tools used include measuring cups and funnels to pour the ingredients into the centrifuge tube. This centrifuge tube would already be placed in the middle of the volcano. For the slow magma eruption (low viscosity), a chopstick was used to help stir the baking soda with the vinegar and Quik. The vinegar and the baking soda had their separate measuring cups and funnels to keep the activity clean. The volcano and magma ingredients are based out of the G.E.M.S. guide.

Working with two patients, ages four and five, Colleen and I helped them erupt their volcanoes. Unfortunately, several patients were unable to participate in erupting volcanoes after the reading of the book. We talked about what magma is (molten rock) and that it cools above ground as lava to form into rock again. I explained that we are going to create two different types of volcanic eruptions: one that is smooth and gentle and another that will be explosive- but not too explosive. We emphasized that the chemical we are working with are friendly ingredients used in cooking our food. Unlike read magma, we do not have to worry about being burned by the magma we are creating today. The ingredients were prepared and measured out for each patient as they poured the mixture into their volcanoes. Both patients preferred that we do one at a time so the other could watch. The first eruption involved an example of a slow, fluid lava flow. The ingredients for this eruption included baking soda, vinegar, and Quik. From here I reinforced that the idea that this mixture, which represented magma, was safe to touch and that it wouldn’t hurt you. The patients poured in the vinegar/Quik mixture first followed by the baking soda. After the baking soda was poured into the tube, each child stirred the ingredients promoting the chemical reaction that poured over their fingers. The patients were hesitant of what was going to happen and enjoyed seeing the Strawberry lava poured from the top the volcanoes.

(Used with written permission)

Next came the exciting part: the explosive eruption. Well, not really that explosive, but it left this next eruption with a pop and grew anticipation with the patients. Once again, all ingredients were pre-measured and mixed before the patients poured them in with a funnel. For the explosive eruption, emphasis was placed on the fact that some magma does not easily release gas bubbles. Because most of these gas bubbles are not released, tremendous pressure builds up until the volcano erupts. In our case, we mix the baking soda to the vinegar and then quickly plug the centrifuge tube. This plug needs to be placed very quickly to get the best effect. First, the patients pour in the baking soda and then the tricky part- once the vinegar and red-food coloring is poured in, the funnel needs to be removed quickly and the plug placed deep enough so more pressure is required to pop the plug off of the top of the volcano. The patients are obviously excited once I explain to them this next step with vinegar to pour in one hand and the plug to the centrifuge in their other hand. After the vinegar is poured in, the magma begins to bubble up as I remove the funnel. The patient urgently places the plug in the centrifuge! We all sit back and wait. Seconds pass in anticipation. Pop! Gleeful laughter erupts from the patients as the plug shoots upward from the volcanoes and lands a short distance at its base. As a side-note, after creating these volcanoes, they were all sprayed with a sealer so the baking soda/vinegar, red food coloring could be wiped away after each eruption and ideally re-used multiple times.

We talked about how scientist observe subjects such as volcanoes and record what they see with pictures, photographs and the written word. After each eruption, we asked the patients to draw what they observed on prepared activity sheet.

After working with these two patients, I went to three rooms where did a condensed version of my lecture to patients, their siblings, and parents. Bringing my vesicular basalt was a last minute thought and I was happy I did so. These rocks were a great jumping off point when I began talking about gases in magma and how some gases escape easier in some magma than in others. It was significant that those that I talked to were able to hold and experience volcanic rock. More importantly is the fact that these rocks are from Minnesota and not from some far off land. In some of the rooms, I had more conversations with the parents than I did with the patients! Of the two volcanic eruptions Colleen and I had created earlier, I only modeled the explosive volcanic eruption since their take-away bags had the example of the smoother eruption.

Thirteen take-away bags included a 6 oz. container with pre-mixed vinegar and red food coloring, one container of baking soda, and an information card with our logo, ingredients to make more magma, the explanation of the chemical reaction taking place when the baking soda and vinegar are mixed, instructions when mixing this magma, and sources to help with making your own volcano. These items were placed within a plastic bag and handed out to participating patients and to those who missed this activity. (Note: the container in this photograph is a 12 oz. container and not a 6 oz. container)

Thank you to Dr. Maggie Hoody for providing me with the G.E.M.S. book, ideas for the day, and numerous supplies. Thanks also to Cristen Schwab for laminating the take-away cards.

Activity Sources:
G.E.M.S. Lawrence Hall of Science. Plate Tectonics: The Way the Earth Works, written by Kevin Cuff with Ian Carmichael and Carolyn Willard

Kelly James Schrandt

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