The UEA volcanologists are in a pretty astonishing and unusual position. We know our Norfolk volcano is going to erupt sometime around 1830 on the 28th of Sept 2013. That level of forecasting precision is sadly in the realms of science fiction, but we’re working on getting better!
To do this volcanologists need to gather some fundamental data about how they work. That brings a LOT of challenges: being in the right place at the right time with the right instruments that are all working that can record fast enough, not get trashed and see through vast thick clouds of ash – and all from a safe distance! Phew! Tricky!
So, sometimes, its easier to try and simulate the bit of an eruption that you want to understand. That doesn’t make it time for the lab. coats and teeny weeny test tubes though – oh no! Volcano experiments can take place outdoors and still involve a good amount of whizzes, bangs and excited scientists (just like the Norfolk Volcano). This does gather data it would otherwise be almost possible to get, and not only that but lets scientists do the experiments again and again to check they have reproducible results.
Here’s a whirlwind tour of some cool experimental fun with a couple of ‘do try this at home‘ experimental tips thrown in for good measure at the bottom cos its the School Holidays!
This first video is a pretty ‘straightforward’ volcano experiment – it involves melting of actual basalt (and that means temperatures in excess of 1200 degrees centigrade) and then pouring it. Don’t whizz through the clip to get to the exciting red stuff either, the Faculty involved in the Syracuse Lava Project do a great job of describing the value of this kind of experiment in becoming an independent learner as well as understanding the hot gooey stuff and how it rolls.
The second is a really brilliant example of how changing one variable in the system can change everything. This is a series of experiments done by Syracuse along with long time UEA friend Ben Edwards from Dickinson College. He was interested in how lava interacted with ice and wanted to use these experiments to help him interpret volcanic deposits he found in the field and observations from recent eruptions. The interaction of lava and ice is a hazardous combination and Ben recently published a paper in Geology about how much his experiments can tell us, you can read more about it here.
The third clip is about explosions! This facility at the University of Buffalo, USA has been used to help the geologists there work out how much energy is involved in volcanic explosions when all they leave behind are craters. This now involves materials that are analogues for the real situation: TNT to create the explosion and pits of loose gravel.
This is the United States Geological Survey Experimental Flume Facility. Its basically a giant concrete chute in a forest in Oregon. Mixtures of volcanic debris +/- water can be sent up to 100m down the chute again and again to allow measurements of important features of these flows.
It would be remiss not to include the UEA version of ‘volcano in a bin’! Although this is the least ‘natural’ analogue for volcanic behaviour it still involves the ‘critical failure’ that also drives some volcanic explosions. The dispersal of the balls has just the same laws of physics acting on it as those that drive the movement and distribution of volcanic particles. If you like the look of this then come to the Family Fun Day on the 28th of September *knowing wink* !
Do Try this at Home! (with adult supervision)
If you can’t wait til then here are some fun volcano-related experiments you can try in the back garden
The Alka-seltzer and film cannister explosion.
You need: A little plastic container that is used to contain photographic film (remember ‘film’ so retro, man. Ask in a chemist where film is developed; they usually have bags of spares — Fujifilm cannisters are the best!). Alka Seltzer. Water. Eye protection, just incase.
To do: Put on your eye protection. Put a little bit of bit of the alka seltzer tablet in the bottom of the cannister. Add a few drops of water (to cover the base of the container). Put lid on. Shake. Stand back (a few metres) Bang!
What is it like? The gas released by the reaction between that water and the tablet build up pressure in the container. It fails at the weakest point which is around the lid and all the stored energy is released as an explosion as the gas expands rapidly into the atmosphere. All volcanic explosions are driven by the release of gas from their magma, some ‘fail’ like this driving a single short-lived explosion.
Fun Variant: put some paper under the explosion and some paint in the canister. Record your explosive Art! If mixing paint and children is not your definition of ‘fun’ then avoid this variant.
The Coke and Mentos Conduit.
You will probably have seen by now the frenetic degassing that happens when mentos are dropped into coke to trigger the reaction. If not, look here.
What is it like? Changes during larger volcanic eruptions can be driven by the erosion of the crater around the explosion or the conduit that brings the material to the surface. This lets you see the impact this has how on high the eruption column goes.
You Need: Diet Coke, Mentos (minty ones are best), not to be wearing your Sunday best. Eye protection.
To do: Don eye protection. Do one experiment by dropping the mentos into the coke as fast as you can (there all sorts of ingenious ways to do this). Now cut off the top of the bottle for your next experiment; this leaves a slightly larger hole. I’m not going to tell you how it changes; you can find that out.
Fun Variants: You can create a ‘jet’ by putting the lid on the coke bottle, making a tiny hole in the top and figuring out how to release the mentos into the coke with this configuration (unbent paper clips are involved). If you don’t like mess on your lawn then avoid this entire experiment but well done for getting this far with the blog post!
Fudge Lava (one for a rainy day and it really needs full adult cooperation!):
There are two types of basaltic lava flow (pahoehoe is seen in the Syracuse Lava Experiment above; a’a is shown here). This recipe for fudge will let you see how growing crystals inside your fudge magma has a big impact on how it flows – and you get to eat it afterwards!