Despite the fact that methane is a powerful greenhouse gas itself and burning it produces carbon dioxide there is currently quite a bit of research on extracting methane hydrates from the sea floor as an alternative to the traditional fossil fuels because there is just so much of it. Discovery Channel has an interesting video on the topic where they burn some methane hydrate ice.
Methane releases from the arctic and sea-floor could also trigger rapid climate change. Recent discoveries suggest that global warming is warming the arctic so much that the permafrost is melting an releasing a lot of methane into the atmosphere. If the arctic atmosphere continues to warm, more methane will be released, causing more warming …. This positive feedback loop would accelerate global warming. Some scientists worry that warmer ocean waters can melt methane hydrates at the sea floor releasing them into the atmosphere in a similar positive feedback loop.
How do solar cells (photovoltaic cells) work? There are very simple explanations, but you can probably find a video with any level of complexity you might want.
This video from the U.S. Department of Energy is fairly general and makes a nice introduction:
The assimilation of viral sequences into the host genome is a process referred to as endogenization. This occurs when viral DNA integrates into a chromosome of reproductive cells and is subsequently passed from parent to offspring. – University of Texas at Arlington (2010)
The hydroelectric dam at Pickwick Landing on the Tennessee River is an almost ideal place to observe electricity generation and transmission. It was a serendipitous discovery though. After our failure to arrange a tour of a dam in Arkansas on the last immersion, we did not even try with this one.
The dam is right next to Pickwick Landing State Park where we camp when visiting the Shiloh National Battlefield. We’d arrived early at the park on the day before our visit to Shiloh, and having seen the dam and its locks on Google Maps’ satellite image (click the satellite button on the map above), I thought it might be useful if we drove over.
Turbine for hydroelectric dam. High voltage power lines in the background.
Coming around the northern side of the dam we spotted, right next to a parking lot, an old turbine from the dam that had been set up for display. It is amazing how big these things are, but what was really neat is the fact that if you listened, you could hear the whine of the modern turbines coming from the generators deep inside the dam.
Standing over the old turbine was an enormous high-voltage wire tower, sparse metal frame and truncated arms like a benevolent grandparent leaning over a plump, but scared child. The line of towers are connected to the generation station in the dam by power substation just across the street from the old turbine. The substation’s large transformer drums were obvious even from across the road.
Crossing southward over the dam, there is a road that runs westward along the edge of the river that allows a good view of the downriver side of the locks. We were lucky enough to see a barge passing through, although with the traffic on the river the locks are probably always busy.
Barge exiting the lock.
When we got back to the park the students draw a diagrams of the dam. They don’t do nearly enough diagrams given the importance of drawing in connecting the body and the mind (something I plan on rectifying in the next cycle) so this was a good experience for them. It was also a reminder to always keep their writer’s notebooks with them because then they could have drawn their diagram while they were at the dam looking at the thing.
The BBC has an excellent video demonstration by Maggie Aderin-Pocock of how to demonstrate how additional carbon dioxide in the air results in global warming. She uses baking soda and vinegar to create the CO2 and lamps for light (putting the bottles in the sun would work just as well). You’d also probably want to use regular thermometers in the bottles if you don’t have ones that connect to your computer.
