On Wednesday, the Herons created sundials. We began with a lesson on how to use the scroll saw. Ryan, Amy and I are trying to introduce more tool use into the curriculum before the students use the tools in Village. Needless to say, the opportunity to use a power tool to cut our gnomon to size was greeted enthusiastically.
The sundial needs to be aligned east and west so we used a compass to find north. However, when we laid our compasses down on the plaza to set everything up, the needle spun wildly. After a lot of good hypothesizing, the Herons surmised that there must be something magnetic in the cement. (Indeed, way back in 2009 we paid extra to have sparkly concrete in the plaza checkerboard. I suspect that is the culprit foiling our compass readings. Curse our vanity!). We ended up using the edges of the concrete that are very close to east and west. On the hour from 10:00 to 2:00 we marked the progress of the sun's shadow. A lot of the Herons were surprised to find that the shortest shadow (solar noon) happened just after 1pm. We'll be exploring more about that soon.
Today we learned more about how the Egyptians used sundials. They divided the daylight into twelve parts and each part was called an hour. The Herons quickly realized that Egyptian hours would be longer in the summer and shorter in the winter since it's just 1/12 of the daytime. They also realized that cloudy days (and night) would make it impossible to tell time.
We paired up to brainstorm possible solutions to cloudy day time keeping. They had plans for a clock that dropped water at a steady pace into bowls that would fill in an hour. Another suggested that instead of a bowl, you use a rain gauge type tube that would be marked in hours. Another student suggested a candle that would burn down in an hour and you would use twelve candles throughout the day. Several students remembered the noria from our Silk Road adventures last year. They thought about a water wheel that filled up a bowl with water and that then dropped down so that the next bowl would fill up. One group created a plan for a round pebble to travel down a path that would take a certain amount of time. All of these are close to actual solutions that humans created over the course of a thousand years. I'm still amazed that the Herons dreamed them up without knowing that it took the ancients hundred of years to come up with the same ideas.
Some of the Heron's ideas were completely original. One child suggested that water could be put into a circular canal that would move a large lamp around a sundial at the same pace the sun would move at. Another suggested a giant boulder that would be released at the top of a mountain and would crush a series of candles so that you could watch from across the valley and tell how many candles had been crushed to be able to tell the time. When one of the students wondered how you would reset the clock there was some discussion until it was decided that a giant catapult would be the best way to get the boulder back up the mountain. That's my kind of solution!
All of the students soon realized that having a steady, measurable unit was key to keeping time. It was not long before "The Macarena" was suggested as something we could repeat to keep track of time. A single Macarena took 9 seconds (well, 9.14 seconds but we've not yet discussed a "leap Macarena"). So by singing the Macarena over and over and over and over, we could keep track of time in 9 second intervals. The hilarious (at least to me) results are below. Enjoy!