Lava Layering... Create mini volcano eruptions and build a volcano from layers of lava! What you’ll need: • Food colouring • Play dough • Tray • Film canister • Baking soda • Vinegar • Straw • Tissues What to do: 1. Place one tablespoon of baking soda in the film canister on the tray. 2. Add 3 drops of food colouring. 3. Fill the film canister with a small amount of vinegar. 4. Watch the eruption of "lava." 5. Mop up the "lava" with the tissues. 6. Use coloured playdough to cover the areas where "lava" flowed. 7. Repeat steps 1-4 with different colour food colouring and playdough. 8. You should see your volcano take shape as new "lava" covers or overlaps the older flows. 9. Pierce the volcano with the straw, pushing the straw through to the bottom of the volcano. 10. Carefully pull out your straw. Then blow through the straw- the playdough ‘core’ should pop out. 11. Draw what you see in the vertical section. 12. Colour your sketch and add these labels: oldest flow, youngest flow. Jo has fun making her own volcano! What's happening? The ‘lava’ is actually lots of carbon dioxide gas bubbles that are produced when you mix and acid (the vinegar) with a base (the baking powder). Cutting though the play dough volcano layers gives you a ‘core’ revealing the layers of lava flow that have made up the volcano. The study of rock layers is called stratigraphy. Field geologists use differences in roughness, colour, and chemistry to further differentiate between lava flows. For example, old lava flows are usually more eroded and have more vegetation than young flows. Did the flows always follow the same path? What do you think influences the direction lava flows?. Geologists look at the overall slope of the land, local features such as small cliffs and depressions, channels, and levees to try to trace lava flows back to the source area. You can also study lava flows on the moon! Lava on the moon generally flowed long distances and flood low-lying areas such as the floors of big craters. The eruption sources for most of the lava flows on the Moon are difficult to find because they were buried by younger flows. Maps of the Moon show complicated lava flows, some in layers. Credit: With thanks to SciZmic science clubs and The ASU Planetary Group Go back