Hawai'i Space Grant Consortium, Hawai'i Institute of Geophysics and Planetology, University of Hawai'i, 1996

Lava Layering
Purpose

To learn about the stratigraphy of lava flows produced by multiple eruptions.

Key Words

eruption

source

stratigraphy



Materials

paper cups, 4 oz. size, some cut down to a height of 2.5 cm

cafeteria tray or cookie sheet, 1 for each eruption source

tape

tablespoon

baking soda

measuring cup

vinegar

food coloring, 4 colors; for example, red, yellow, blue, green

playdough or clay in the same 4 colors as the food coloring

Procedure
1.
Take one paper cup that has been cut to a height of 2.5 cm and secure it onto the tray. (You may use a small loop of tape on the outside bottom of the cup.) This short cup is your eruption source and the tray is the original land surface.

2.
Place one Tablespoon of baking soda in this cup.

3.
Fill 4 tall paper cups each with 1/8 cup of vinegar.

4.
To each paper cup of vinegar add 3 drops of food coloring; make each cup a different color. Set them aside.

5.
Set aside small balls of playdough, one of each color.

6.
You are now ready to create an eruption. Pour red-colored vinegar into your source cup and watch the eruption of "lava."

7.
As best you can, use red playdough to cover the areas where red "lava" flowed.

8.
Repeat steps 6 and 7 for each color of vinegar and playdough. You may add fresh baking soda to the source cup or spoon out excess vinegar from the source cup as needed.


Results
1.
After your four eruptions, can you still see the original land surface (tray)? Where?

2.
Describe what you see and include observations of flows covering or overlapping other flows. Make a sketch.

3.
Where is the oldest flow?

4.
Where is the youngest flow?

5.
Did the flows always follow the same path? (be specific)

6.
What do you think influences the path direction of lava flows?

7.
If you had not watched the eruptions, how would you know that there are many different layers of lava? Give at least 2 reasons.

8.
Which of the reasons listed in answer 7 could be used to identify real lava layers on Earth?

9.
What are other ways to distinguish between older and younger layered lava flows on Earth?

10.
Which of the reasons listed in answer 9 could be used to identify lava layers on the Moon?

11.
What are other ways to distinguish between older and younger layered lava flows on the Moon?

12.
Make a vertical cut through an area of overlapping playdough "lava" layers. Draw what you see in the vertical section. Color your sketch and add these labels: oldest flow, youngest flow.



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