Marcus did a presentation of types of lava flow as a writing assignment for co-op. He presented it to his class and their parents. He only had 1.5 weeks to write the report and put a presentation together. Again, he surprised me by working very independently and with unexpected maturity. I guess this is the new normal. Phew, I thought that would never happen. Sometimes I have to remind myself that he is only 9.
Earthly Innards
You have probably heard of lava and its incomprehensible power of destruction, but did you know that scientists classify lava flow into four different categories, depending on what it looks like, the speed at which it travels and the temperature reached by the glowing ooze. Pahoehoe, a’a, pillow, and block lava are all unique and pose a significant threat to environments and people who exist within the shadows of volcanoes.
A’a lava forms when lava tumbles over itself in a mess of broken fragments of harder, cooled lava called clinkers. Some say it moves like the tread of a bulldozer. The tumbling movement results in rough, sharp points and edges making hiking on these black fields almost impossible. It consists of mainly basalt and contains little silica, meaning it’s thin and runny, or of low viscosity. The speed at which a'a tumbles over itself can reach 160 km/h and at a temperature of around 1100 degrees celsius, you surely want to stay out of its way. Various gasses trapped within the molten flow result in a shiny, colourful display within the otherwise dark chunks of igneous rock. This lava type usually erupts from shield and stratovolcanoes.
Block lava forms and flows the same way as a’a lava, but because of its higher viscosity, it hardens into blocks instead of clinkers. It’s composed of andesitic and rhyolitic material, and has a high silica content, meaning that it's thick and sticky when molten. This is mostly found erupting from stratovolcanoes and lava domes. This is the least hot type of lava with a temperature range of 760 - 927 celsius. This is also the most sedate type, with a top speed of only 4.5 meters per day!
Pahoehoe can reach temperatures in excess of 1200 degrees celsius, but tends to move and cool slower than a’a. This lava flows in lobes called toes, cooling into a rope-like texture. If pahoehoe lava is forced to continue flowing after it's cooled to a critical temperature, it will start tumbling over itself, and will result in rough a’a clinkers forming. Pahoehoe is of low viscosity and composed of mostly molten basalt. It regularly erupts out of shield volcanoes and is also interestingly the easiest flow type for pioneering plants to reestablish on.
Pillow lava forms when a submarine volcano erupts. This lava is essentially pahoehoe lava, but because of its contact with water, hardens into rounded, pillow- like shapes. Pillows quickly form in the cool water, but inner lava can reach a scorching 1200 degrees celsius. Its composition is basaltic and andesitic and as with pahoehoe, it forms with slow effusion. Without surprise, this is the most abundant lava type found all over the submarine areas within the ring of fire! Pillow lava can also be found on extinct volcanoes that erupted out of ancient oceans and arose above the water level, as seen on the Mauna Kea in Hawaii.
Lava captivates our attention and imagination in the way it slithers, slips and spills while shaping our planet. It’s a destroyer, a creator and a conserver all at once. Lava fascinates, awes and kills, while enchanting us into exploring its molten mysteries.
Earthly Innards
You have probably heard of lava and its incomprehensible power of destruction, but did you know that scientists classify lava flow into four different categories, depending on what it looks like, the speed at which it travels and the temperature reached by the glowing ooze. Pahoehoe, a’a, pillow, and block lava are all unique and pose a significant threat to environments and people who exist within the shadows of volcanoes.
A’a lava forms when lava tumbles over itself in a mess of broken fragments of harder, cooled lava called clinkers. Some say it moves like the tread of a bulldozer. The tumbling movement results in rough, sharp points and edges making hiking on these black fields almost impossible. It consists of mainly basalt and contains little silica, meaning it’s thin and runny, or of low viscosity. The speed at which a'a tumbles over itself can reach 160 km/h and at a temperature of around 1100 degrees celsius, you surely want to stay out of its way. Various gasses trapped within the molten flow result in a shiny, colourful display within the otherwise dark chunks of igneous rock. This lava type usually erupts from shield and stratovolcanoes.
Block lava forms and flows the same way as a’a lava, but because of its higher viscosity, it hardens into blocks instead of clinkers. It’s composed of andesitic and rhyolitic material, and has a high silica content, meaning that it's thick and sticky when molten. This is mostly found erupting from stratovolcanoes and lava domes. This is the least hot type of lava with a temperature range of 760 - 927 celsius. This is also the most sedate type, with a top speed of only 4.5 meters per day!
Pahoehoe can reach temperatures in excess of 1200 degrees celsius, but tends to move and cool slower than a’a. This lava flows in lobes called toes, cooling into a rope-like texture. If pahoehoe lava is forced to continue flowing after it's cooled to a critical temperature, it will start tumbling over itself, and will result in rough a’a clinkers forming. Pahoehoe is of low viscosity and composed of mostly molten basalt. It regularly erupts out of shield volcanoes and is also interestingly the easiest flow type for pioneering plants to reestablish on.
Pillow lava forms when a submarine volcano erupts. This lava is essentially pahoehoe lava, but because of its contact with water, hardens into rounded, pillow- like shapes. Pillows quickly form in the cool water, but inner lava can reach a scorching 1200 degrees celsius. Its composition is basaltic and andesitic and as with pahoehoe, it forms with slow effusion. Without surprise, this is the most abundant lava type found all over the submarine areas within the ring of fire! Pillow lava can also be found on extinct volcanoes that erupted out of ancient oceans and arose above the water level, as seen on the Mauna Kea in Hawaii.
Lava captivates our attention and imagination in the way it slithers, slips and spills while shaping our planet. It’s a destroyer, a creator and a conserver all at once. Lava fascinates, awes and kills, while enchanting us into exploring its molten mysteries.
Danae had to do the same thing. She chose the "Green Sands of Hawaii" as her topic. She also did amazingly well. It was her first ever presentation in front of people and she had no problems with it. Actually, she really enjoyed it. I'm looking forward to the next one where she will know what to expect more. I also wish the teacher gave her more than 3 days to prepare!
Mysterious Green Sand of Hawaii
You may think that green sand is something that only exists in my imagination. I am here to tell you that there is a whole shimmering beach of it on the island of Hawaii. This odd looking sand is composed of the mineral olivine. It is formed inside the glowing magma of a turbulent volcano. Digging your hands into nature’s own laboratory will change your mind into believing that this sand is real.
Mysterious Green Sand of Hawaii
You may think that green sand is something that only exists in my imagination. I am here to tell you that there is a whole shimmering beach of it on the island of Hawaii. This odd looking sand is composed of the mineral olivine. It is formed inside the glowing magma of a turbulent volcano. Digging your hands into nature’s own laboratory will change your mind into believing that this sand is real.