Hoover Dam

I interrupt our Denmark Unit to bring you this special coverage of the Hoover Dam. Would you believe me if I said the boys were just as excited about going to the Hoover Dam as they were about going to Disneyland? Our trip to Flaming Gorge just whetted their appetites (the Flaming Gorge guide kept giving stats in relation to the Hoover Dam), so they'd been looking forward to it for a long time. Unfortunately, kids under 8 can't do the longer tour at the Hoover Dam, but we did get to see the powerhouse and everyone seemed content with that. Junie was extra heavy and squirmy and we hadn't brought the stroller, so Sam and I were definitely content with that!

Seb loved this huge wall diagram of the path of water through the powerhouse and dam. Probably because he has drawn many a similar diagram, in his day.

Tunnel toward the old diversion tunnel

The enormous penstock---we got to walk right over it

Powerhouse (Nevada side)---7 of the 15 enormous turbines

Intake towers

Outside 

One of many re-constructions created after we got home (note powerlines coming out of powerhouse toward transformers)

Sprinklers and Irrigation

Of course, you know we had to spend at least a little time studying sprinklers and irrigation systems. We studied some of the irrigation methods throughout history (Egypt and the Nile, the "hanging gardens" of Babylon, etc.) and we read several sections from this book:

which, I should point out, was a great labor of love on my part, since it was very technical and had lots of pages like this in it:

But I knew the boys (especially Seb) would love it, and they did. Side benefit: I now know why our backyard sprinkler system works so poorly (guess we shouldn't have gone with the cheapest bid). Huh, if only I'd read this book a couple years ago!

We did some soil analysis (an exercise from the sprinkler book) and found that our soil here is mostly clay with a bunch of rocks in it. Not ideal, as we knew. But the topsoil we brought in is pretty good (for our herb gardens etc.); I just wish we had more of it.

Hydrologic Cycle, Water Density, and Water Taste Test

The natural starting place for any unit on water is the Hydrologic Cycle. [When I'm teaching and need to draw diagrams, I always just tape up sheets of paper from those IKEA paper rolls on our walls or windows.]

Do you like that penguin? And the . . . eel? (it was supposed to be an otter)

This stuff wasn't new to Abey or Sebby, but we went more in-depth than they'd gone before. When we studied clouds, rain, and lightning, we had to get into static electricity, of course, and later we studied currents (did you ever put together that static electricity is so named as a contrast to moving electricity; that is, a current? I never had. It was eye-opening to realize this) when we talked about hydroelectric power. Those were some of the most interesting parts to me, since I've just never really understood electricity! Yes, after all these years (and I was a good student), I understood some of the separate concepts, but never really the deep-down causes and how they all fit together. I felt like leaping for joy when it finally all came together in my head. So that's why things turn on when we plug them in! But I'm getting ahead of myself.

Robert Krampf has a great, simple video showing how to make a model of the hydrologic cycle.

Nearly all of the books we had on water (even the ones about dams and hydropower) included chapters on the water cycle, so there were lots of chances to review this throughout the unit.

We also spent a couple different days talking about some of the interesting properties of water, like surface tension, boiling and freezing point, density, etc. Having an understanding of the basic atomic structure of water and some of its characteristics was really useful on the other days as we studied things like lightning and electricity.

We did a demonstration to compare the densities of oil, water, and corn syrup (you drop in different objects and see where they float). This also showed the intermolecular polarity of oil and water.

We did a couple different experiments with water convection currents and the densities of different temperatures of water---this one is called the "underwater volcano"

The watched pot boiling

Robert Krampf has some good videos on water:
http://thehappyscientist.com/science-video/watched-pot
http://thehappyscientist.com/science-video/boat-full-holes
http://thehappyscientist.com/science-video/wonderful-water
http://thehappyscientist.com/science-video/density-column

I also thought it would be interesting to do a taste test of different types of water. We boiled some water and drank that when it cooled, along with boiled water shaken up (to re-dissolve gases from the air into it), tap water, and a few different kinds of bottled water. This led to a really fun discussion of why people buy bottled or filtered water and whether we think it's worth the price (we don't, but then, our water is the second-best in the nation!). :) Of the bottled waters, Sebby and Abe did prefer the taste of "SmartWater," though!