Water Pressure

I don't have a lot of pictures, but understanding water pressure is essential to understanding how dams and water towers and pipe systems work, so we had a lot of discussion about it (and, peripherally, air pressure). Along with the bottle demonstration pictured above, the older boys were delighted to play this trick on Sam. We also used Sebby's straws (he got these for his birthday a couple years ago) to experiment with the ways that pipe thickness, distance, gravity, etc. affect water pressure.

They took their hole-y water bottles outside and pretended they were water towers (enterprising Abe, whose bottle worked fastest, was charging "money" for the others to fill their cups at his water tower)

We talked about clouds and rain and lightning on one of the days (just briefly; we will do a longer unit on weather sometime because there's lots more to cover!), and made these clouds in a bottle. We also loved making "lightning" with balloons and light bulbs (as described here and here). We did this demonstration in my closet and the kids LOVED it. They were all giggly and nervous there in the dark at first, not knowing what would happen, but after we made it work a few times, they could hardly be persuaded to stop! [note: We used a CFL and I thought it looked much more impressive with that than with his long fluorescent bulb in that second link, but I do really like his explanation of volts vs. amps and how fluorescent bulbs work. ]

A couple other good resources we used on water and air pressure:

http://thehappyscientist.com/science-experiment/feeling-pressure

http://www.asme.org/kb/news---articles/articles/k-12-grade/5-ways-to-demonstrate-air-pressure-to-children

http://thehappyscientist.com/science-video/cartesian-diver

http://www.history.com/shows/underwater-universe/videos/the-science-of-water-pressure#the-science-of-water-pressure

http://www.abc.net.au/spark/experiments/s1199904.htm

Surface Tension

Here are two fun demonstrations to do with surface tension (besides the usual water-drops-on-a-penny, which my kids loved):

This one shows how milk has less surface tension than water

This one shows how a surfactant can decrease the surface tension of a liquid

Waterfalls (and why are waterfalls white?)

Before we talked about dams, we had a day on waterfalls, where we learned about several of the highest/biggest/widest waterfalls on earth, and learned the names of different types of waterfalls. We also took a field trip to hike to one of our favorite waterfalls, Battle Creek Falls.

We took a picnic (split into our several backpacks, although most of the space in mine was taken up by a picnic-eater instead of a picnic) and had a lovely time. It was hot, but so pretty, and the mist felt wonderful!

Malachi helps Daisy

Abe helps Malachi

These fuzzy caterpillars were everywhere! Daisy reacted with a slightly-hysterical nervous laugh whenever one started inching close to her. The rest of us liked them.

Nobody fell down this waterfall, so our field trip was a success! :)

Postscript:

I was telling Sam about our field trip as we went on our date that night, and he said, "Here's something interesting: do you know why waterfalls are white-colored?" I didn't, so we spent a good portion of our date having a lively discussion about it---nerdy, but just the sort of thing we like. Another indication that we were meant for each other, and that this homeschooling adventure is a good thing for our family. :) 

Sam's explanation was the best (this is exactly the type of thing his lighting class is about) but here is another video which also explains this interesting phenomenon.

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.

Waterwheels and Water Play Table

The first day of the unit was Sebby's actual birthday, and his birthday present was this waterwheel play table. I deliberated about it for quite awhile, because the target age for the table is much younger than Seb, but I just had a feeling he'd like it anyway. He is always wanting to play with various toys in the sink (send his cars down "waterslide" ramps etc.), so I thought he'd appreciate having a dedicated place to do such play (without me always saying "Don't play with the water!"). I decided even when he got tired of it, the little ones would still have fun playing in it.

It has a waterwheel on it, which they find all sorts of uses for.

And, so far, Seb's not tired of it! Even Abe still has fun playing in the water and they ask to go out there all the time. They make up all sorts of games and swim their little animals around in it and so forth.

Anyway, if you want to study water power, you can find lots of resources online for making mini-waterwheels. We tried a couple variations (here and here), and even got one to lift a bag of rocks for us. Fun!

That night we visited this waterwheel at Gardner Village (which used to be a mill run by my great-great-great-great [?] uncle, Archibald Gardner). It's fun to see a real waterwheel at work, though it can't quite compare with the one we saw actually turning a millstone at Benson Grist Mill.

Waterpark Field Trip, and How Water Slides Work

On the childrens' birthdays, we have a tradition of doing something fun together as a family. (We usually only give 1-2 gifts, so their activity is sort of their gift as well.) For Daisy's birthday we went to the Aquarium and for Seb's, we went to a waterpark. Now this sounds like one of those "mostly-just-fun-thing-trying-to-justify-itself-as-'educational'" types of Field Trips---and I would have been totally fine with that, since this was actually a birthday activity, after all---but surprisingly, the lesson leading up to this Field Trip was one of the most interesting and informative of the whole unit, I thought. We had a library book on "how water parks are built," but I thought the most useful resource we used was this website. It has diagrams of the parts of a water park system (the pumps and filters that keep the water moving), explanations of kinetic and potential energy, and more. It was awesome. From this same site, we learned about "water coasters" (we'd never heard of those!) which use strong currents or magnets to push you UP hills as well as down---like a roller coaster in the water. We looked up a bunch of videos so we could see those in action. (e.g. here)

Seeing how these concepts are applied in real life added substance to our discussion of inertia, friction, thrust and drag, types of energy, etc. And it was great to see the children running around at the water park calling out things like, "Look Mommy! Cantilevers!" and "Whoa, did you see the way my inertia pulled me up the side of that curve?"

Also, we just had a fun time. :)

I'm cold.

Splash!

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!

Water Unit Schedule/Lesson Plans

This unit was so big that I felt like this lesson plan deserved its own post. I decided at the beginning of the summer that since Seb's and Daisy's birthdays both fell in August, we would study something each one really liked during his or her birthday week. For Sebby's week, we chose to study water, and because it's such a huge subject, so we planned three weeks for it. (And of course, we weren't trying to cover EVERYTHING about water---we left out marine life and a million other potential foci.) For this unit, I focused mostly on the ways water works for people: hydropower, irrigation, pipe systems, etc. We learned about those properties of water that were applicable to these areas (surface tension, density, water pressure, and so forth).

It was a fascinating unit and we loved it!

Aquarium penguins

To go with our Penguin Unit, we went to the aquarium because they have penguins there! This normally would have been too expensive of a field trip, but since we usually do a family activity for birthdays anyway, we counted this as Daisy's birthday present. (Warning: all these pictures are terrible, but they remind me of a nice day, so I look at them fondly anyway.)

I went to the aquarium with Abe's school class last year and he's been wanting to go back with the family ever since. The aquarium has grown a lot since we first went there seven years ago (the day I was in labor with Sebby---at that time it was just a big empty room with some stingrays in a tank and, like, an octopus. Super disappointing.) and it's quite fun. I think they are dreaming of/ fundraising for a bigger space (of course they are; when is a place like this not fundraising?!) and I can see that several of the exhibits are not . . . ideally situated (e.g. none of the kids could really see the penguins on land, since the waterline was above their eye level, and of course there are big "NO CLIMBING" signs on any surface that might be remotely helpful in boosting them up). Still, we really liked the penguins (they are Gentoo Penguins, which look like they have little white headbands on. So cute!) best, but we really enjoyed everything. There's a display where you can get an electric shock like you'd get from an electric eel, which of course all the children had to try 500 times. We liked the otters a lot, too.

Cute baby sharks

Little Blue Penguin and little pink baby

Daisy was riveted to this exhibit

Penguin Races

It kind of looks like Daisy is dressed as a penguin, but it's really her panda bear suit (but that gives me an idea for Halloween!)

These penguin egg races were way too hard to actually carry out (the rice-filled sock "egg" just would NOT stay on anyone's feet, not even for a moment) but luckily, these people don't really need to be accomplishing something or succeeding at a task in order to have a huge amount of giggling, silly fun.